@article{hostettere_gardner_sillett_pollock_simons_2019, title={An integrated model decomposing the components of detection probability and abundance in unmarked populations}, volume={10}, ISSN={["2150-8925"]}, url={https://doi.org/10.1002/ecs2.2586}, DOI={10.1002/ecs2.2586}, abstractNote={Abstract}, number={3}, journal={ECOSPHERE}, publisher={Wiley}, author={Hostettere, Nathan J. and Gardner, Beth and Sillett, T. Scott and Pollock, Kenneth H. and Simons, Theodore R.}, year={2019}, month={Mar} }
 @article{cove_simons_gardner_allan f. o'connell_2019, title={Towards recovery of an endangered island endemic: Distributional and behavioral responses of Key Largo woodrats associated with exotic predator removal}, volume={237}, ISSN={["1873-2917"]}, DOI={10.1016/j.biocon.2019.07.032}, abstractNote={Exotic predators create novel ecological contexts for native species, particularly when prey exhibit predator naïve behaviors. Population recovery of island endemic species following predator eradication has been documented broadly, but studies examining mammalian prey behavioral responses to exotic predator removal are less common. The Key Largo woodrat (Neotoma floridana smalli) is an endangered Florida endemic species that exhibited drastic declines, signified by the loss of natural stick-nests, over the past three decades due to habitat loss and effects from exotic predators. We conducted camera trap surveys of woodrats at supplemental nests and used dynamic multistate occupancy models to evaluate changes in woodrat distribution and stick-nest building behavior over a two-year period of exotic predator (domestic cats [Felis catus] and Burmese pythons [Python bivittatus]) removal. The distribution of woodrats using supplemental nests increased from 27% to 39% in the two-year period, while the proportion of occupied supplemental nests with stick-nests increased from 37% in 2013 to 54% in 2015. The probabilities of supplemental nest use and stick-nest building behavior increased over time following a gradient away from the northern extent of Key Largo, an area associated with high cat activity and the only sites of python captures during the surveys. Woodrats that built stick-nests were more detectable than those that did not, which suggests that stick-nest building could make woodrats more susceptible to predation from novel predators when performing the behavior. We documented increasing woodrat occurrence, along with increasing stick-nest building behavior, which supports recovery and management objectives focused on exotic predator removal.}, journal={BIOLOGICAL CONSERVATION}, author={Cove, Michael V and Simons, Theodore R. and Gardner, Beth and Allan F. O'Connell}, year={2019}, month={Sep}, pages={423–429} }
 @article{cove_gardner_simons_allan f. o'connell_2018, title={Co-occurrence dynamics of endangered Lower Keys marsh rabbits and free-ranging domestic cats: Prey responses to an exotic predator removal program}, volume={8}, ISSN={["2045-7758"]}, DOI={10.1002/ece3.3954}, abstractNote={Abstract}, number={8}, journal={ECOLOGY AND EVOLUTION}, author={Cove, Michael V. and Gardner, Beth and Simons, Theodore R. and Allan F. O'Connell}, year={2018}, month={Apr}, pages={4042–4052} }
 @article{felton_pollock_simons_2018, title={Response of beach-nesting American Oystercatchers to off-road vehicles: An experimental approach reveals physiological nuances and decreased nest attendance}, volume={120}, ISSN={0010-5422 1938-5129}, url={http://dx.doi.org/10.1650/CONDOR-17-84.1}, DOI={10.1650/condor-17-84.1}, abstractNote={ABSTRACT Shorebird populations face increasing challenges as rising sea levels and growing human populations constrain their breeding habitats. On recreational beaches, the nesting season often coincides with a season of high visitor use, increasing the potential for conflict, which may negatively influence beach-nesting shorebird species. We designed a field experiment to study the responses of nesting American Oystercatchers (Haematopus palliatus) to off-road passenger vehicles (ORVs) at Cape Hatteras and Cape Lookout National Seashores in North Carolina, USA. We used continuous video and heart rate recordings to assess changes in the behavior and physiology of incubating oystercatchers. We conducted driving experiments affecting 7 nesting pairs in 2014 and 19 nesting pairs in 2015, between April and July of each year. Experimental treatments were repeated throughout the incubation period for each nest. Although responses were highly variable within and among pairs, paired randomized permutation tests indicated that, overall, oystercatcher pairs spent a greater proportion of time with their heads up and exhibited slower heart rates during driving treatments. Pairs also left their nests more frequently and attended their nests for a lower proportion of time during driving treatments, although these responses diminished over time. Higher nest attendance and lower departure rates late in incubation may have reflected a stronger attachment to nests closer to hatching or habituation to the driving treatment, although individuals continued to exhibit physiological responses to passing vehicles throughout incubation. Beach-nesting birds may benefit from reduced vehicle traffic at their nesting sites, allowing parents to spend more time attending the nest and less time on defensive behaviors.}, number={1}, journal={The Condor}, publisher={Oxford University Press (OUP)}, author={Felton, Shilo K. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2018}, month={Feb}, pages={47–62} }
 @article{denmon_heath_sanders_simons_jones_2017, title={American Oystercatcher}, volume={40}, ISSN={1524-4695 1938-5390}, url={https://bioone.org/journals/waterbirds/volume-40/issue-sp1}, DOI={10.1675/063.040.sp113}, number={sp1}, journal={Waterbirds}, publisher={Waterbird Society}, author={Denmon, P. and Heath, S.A. and Sanders, F.J. and Simons, T.R. and Jones, S.L.}, year={2017}, month={Feb} }
 @book{denmon_heath_sanders_simons_jones_2017, title={American Oystercatcher}, volume={40}, journal={Waterbirds}, author={Denmon, P. and Heath, S.A. and Sanders, F.J. and Simons, T.R. and Jones, S.L.}, year={2017} }
 @article{cove_gardner_simons_kays_o’connell_2017, title={Free-ranging domestic cats (Felis catus) on public lands: estimating density, activity, and diet in the Florida Keys}, volume={20}, ISSN={1387-3547 1573-1464}, url={http://dx.doi.org/10.1007/s10530-017-1534-x}, DOI={10.1007/s10530-017-1534-x}, number={2}, journal={Biological Invasions}, publisher={Springer Science and Business Media LLC}, author={Cove, Michael V. and Gardner, Beth and Simons, Theodore R. and Kays, Roland and O’Connell, Allan F.}, year={2017}, month={Aug}, pages={333–344} }
 @article{felton_hostetter_pollock_simons_2017, title={Managing American Oystercatcher (Haematopus palliatus) Population Growth by Targeting Nesting Season Vital Rates}, volume={40}, ISSN={1524-4695 1938-5390}, url={http://dx.doi.org/10.1675/063.040.sp106}, DOI={10.1675/063.040.sp106}, abstractNote={Abstract. In populations of long-lived species, adult survival typically has a relatively high influence on population growth. From a management perspective, however, adult survival can be difficult to increase in some instances, so other component rates must be considered to reverse population declines. In North Carolina, USA, management to conserve the American Oystercatcher (Haematopus palliatus) targets component vital rates related to fecundity, specifically nest and chick survival. The effectiveness of such a management approach in North Carolina was assessed by creating a three-stage female-based deterministic matrix model. Isoclines were produced from the matrix model to evaluate minimum nest and chick survival rates necessary to reverse population decline, assuming all other vital rates remained stable at mean values. Assuming accurate vital rates, breeding populations within North Carolina appear to be declining. To reverse this decline, combined nest and chick survival would need to increase from 0.14 to ≤ 0.27, a rate that appears to be attainable based on historical estimates. Results are heavily dependent on assumptions of other vital rates, most notably adult survival, revealing the need for accurate estimates of all vital rates to inform management actions. This approach provides valuable insights for evaluating conservation goals for species of concern.}, number={sp1}, journal={Waterbirds}, publisher={Waterbird Society}, author={Felton, Shilo K. and Hostetter, Nathan J. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2017}, month={Feb}, pages={44–54} }
 @article{stocking_simons_parsons_o'connell_2017, title={Managing Native Predators: Evidence from a Partial Removal of Raccoons (Procyon lotor) on the Outer Banks of North Carolina, USA}, volume={40}, ISSN={1524-4695}, url={http://dx.doi.org/10.1675/063.040.sp103}, DOI={10.1675/063.040.sp103}, abstractNote={Abstract. Raccoons (Procyon lotor) are important predators of ground-nesting species in coastal systems. They have been identified as a primary cause of nest failure for the American Oystercatcher (Haematopus palliatus) throughout its range. Concerns over the long-term effects of raccoon predation and increased nest success following a hurricane inspired a mark-resight study of the raccoon population on a barrier island off North Carolina, USA. Approximately half of the raccoons were experimentally removed in 2008. Nests (n = 700) were monitored on two adjacent barrier islands during 2004–2013. Daily nest survival estimates were highest for 2004 (0.974 ± 0.005) and lowest for 2007 and 2008 (0.925 ± 0.009 and 0.925 ± 0.010, respectively). The only model in our candidate set that received any support included island and time of season, along with a diminishing effect of the hurricane and a constant, 5-year effect of the raccoon removal. For both hurricane and raccoon removal, however, the support for island-specific effects was weak (β = -0.204 ± 0.116 and 0.146 ± 0.349, respectively). We conclude that either the raccoon reduction was inadequate, or factors other than predation cause more variation in nest success than previously recognized. A multi-faceted approach to management aimed at reducing nest losses to storm overwash, predation, and human disturbance is likely to yield the largest population level benefits.}, number={sp1}, journal={Waterbirds}, publisher={Waterbird Society}, author={Stocking, J.J. and Simons, T.R. and Parsons, A.W. and O'Connell, A.F.}, year={2017}, month={Feb}, pages={10–18} }
 @article{simons_2017, title={The American Oystercatcher (Haematopus palliatus) Working Group: 15 Years of Collaborative Focal Species Research and Management}, volume={40}, ISSN={1524-4695}, url={http://dx.doi.org/10.1675/063.040.sp102}, DOI={10.1675/063.040.sp102}, abstractNote={Abstract. The American Oystercatcher (Haematopus palliatus) Working Group formed spontaneously in 2001 as coastal waterbird biologists recognized the potential for American Oystercatchers to serve as focal species for collaborative research and management. Accomplishments over the past 15 years include the establishment of rangewide surveys, color-banding protocols, mark-resight studies, a revision of the Birds of North America species account, and new mechanisms for sharing ideas and data. Collaborations among State, Federal, and private sector scientists, natural resource managers, and dedicated volunteers have provided insights into the biology and conservation of American Oystercatchers in the United States and abroad that would not have been possible without the relationships formed through the Working Group. These accomplishments illustrate how broad collaborative approaches and the engagement of the public are key elements of effective shorebird conservation programs.}, number={sp1}, journal={Waterbirds}, publisher={Waterbird Society}, author={Simons, Theodore R.}, year={2017}, month={Feb}, pages={1} }
 @article{rose_simons_2016, title={Avian response to fire in pine–oak forests of Great Smoky Mountains National Park following decades of fire suppression}, volume={118}, ISSN={0010-5422 1938-5129}, url={http://dx.doi.org/10.1650/CONDOR-15-85.1}, DOI={10.1650/condor-15-85.1}, abstractNote={ABSTRACT Fire suppression in southern Appalachian pine–oak forests during the past century dramatically altered the bird community. Fire return intervals decreased, resulting in local extirpation or population declines of many bird species adapted to post-fire plant communities. Within Great Smoky Mountains National Park, declines have been strongest for birds inhabiting xeric pine–oak forests that depend on frequent fire. The buildup of fuels after decades of fire suppression led to changes in the 1996 Great Smoky Mountains Fire Management Plan. Although fire return intervals remain well below historic levels, management changes have helped increase the amount of fire within the park over the past 20 years, providing an opportunity to study patterns of fire severity, time since burn, and bird occurrence. We combined avian point counts in burned and unburned areas with remote sensing indices of fire severity to infer temporal changes in bird occurrence for up to 28 years following fire. Using hierarchical linear models that account for the possibility of a species presence at a site when no individuals are detected, we developed occurrence models for 24 species: 13 occurred more frequently in burned areas, 2 occurred less frequently, and 9 showed no significant difference between burned and unburned areas. Within burned areas, the top models for each species included fire severity, time since burn, or both, suggesting that fire influenced patterns of species occurrence for all 24 species. Our findings suggest that no single fire management strategy will suit all species. To capture peak occupancy for the entire bird community within xeric pine–oak forests, at least 3 fire regimes may be necessary; one applying frequent low severity fire, another using infrequent low severity fire, and a third using infrequently applied high severity fire.}, number={1}, journal={The Condor}, publisher={Oxford University Press (OUP)}, author={Rose, Eli T. and Simons, Theodore R.}, year={2016}, month={Feb}, pages={179–193} }
 @article{cove_simons_gardner_maurer_o'connell_2016, title={Evaluating nest supplementation as a recovery strategy for the endangered rodents of the Florida Keys}, volume={25}, ISSN={1061-2971}, url={http://dx.doi.org/10.1111/rec.12418}, DOI={10.1111/rec.12418}, abstractNote={The Key Largo woodrat (Neotoma floridana smalli) and Key Largo cotton mouse (Peromyscus gossypinus allapaticola) are federally endangered subspecies endemic to the tropical hardwood hammocks of Key Largo, Florida. Woodrats are considered generalists in habitat and diet, yet a steady decline in natural stick nests and capture rates over the past several decades suggests that they are limited by the availability of nesting habitat due to habitat loss and fragmentation. The more specialized Key Largo cotton mouse appears to rely on old growth hammock, a habitat type that is rare following past land clearing. In 2004, the U.S. Fish and Wildlife Service started building supplemental nest structures to restore habitat quality and connectivity for these endangered rodents, but nest use requires evaluation. We used camera traps and occupancy models to evaluate the factors influencing woodrat and cotton mouse use of the supplemental nests. We detected woodrats at 65 and cotton mice at 175 of 284 sampled nest structures, with co‐occurrence at 38 nests. Woodrat nest use followed a gradient from low nest use in the north to high nest use in the south, which might relate to the proximity of free‐ranging domestic cat (Felis catus) colonies in residential developments. Cotton mouse nest use, however, was related positively to mature hammock and related negatively to disturbed areas (e.g. scarified lands). The two species occurred independently of each other. Stick‐stacking behavior was observed at supplemental nests and, although it was correlated with detection of woodrats, it was not a strong predictor of their occurrence. We suggest that nest supplementation can be an important tool for species recovery as habitat quality continues to improve with succession.}, number={2}, journal={Restoration Ecology}, publisher={Wiley}, author={Cove, Michael V. and Simons, Theodore R. and Gardner, Beth and Maurer, Andrew S. and O'Connell, Allan F.}, year={2016}, month={Aug}, pages={253–260} }
 @article{schulte_simons_2016, title={Hurricane Disturbance Benefits Nesting American Oystercatchers (Haematopus palliatus)}, volume={39}, ISSN={1524-4695 1938-5390}, url={http://dx.doi.org/10.1675/063.039.0402}, DOI={10.1675/063.039.0402}, abstractNote={Abstract. Coastal ecosystems are under increasing pressure from human activity, introduced species, sea level rise, and storm activity. Hurricanes are a powerful destructive force, but can also renew coastal habitats. In 2003, Hurricane Isabel altered the barrier islands of North Carolina, flattening dunes and creating sand flats. American Oystercatchers (Haematopus palliatus) are large shorebirds that inhabit the coastal zone throughout the year. Alternative survival models were evaluated for 699 American Oystercatcher nests on North Core Banks and South Core Banks, North Carolina, USA, from 1999–2007. Nest survival on North Core Banks increased from 0.170 (SE = 0.002) to 0.772 (SE = 0.090) after the hurricane, with a carry-over effect lasting 2 years. A simple year effects model described nest survival on South Core Banks. Habitat had no effect on survival except when the overall rate of nest survival was at intermediate levels (0.300–0.600), when nests on open flats survived at a higher rate (0.600; SE = 0.112) than nests in dune habitat (0.243; SE = 0.094). Predator activity declined on North Core Banks after the hurricane and corresponded with an increase in nest survival. Periodic years with elevated nest survival may offset low annual productivity and contribute to the stability of American Oystercatcher populations.}, number={4}, journal={Waterbirds}, publisher={Waterbird Society}, author={Schulte, Shiloh A. and Simons, Theodore R.}, year={2016}, month={Dec}, pages={327–337} }
 @article{rose_simons_klein_mckerrow_2016, title={Normalized burn ratios link fire severity with patterns of avian occurrence}, volume={31}, ISSN={0921-2973 1572-9761}, url={http://dx.doi.org/10.1007/s10980-015-0334-x}, DOI={10.1007/s10980-015-0334-x}, number={7}, journal={Landscape Ecology}, publisher={Springer Science and Business Media LLC}, author={Rose, Eli T. and Simons, Theodore R. and Klein, Rob and McKerrow, Alexa J.}, year={2016}, month={Jan}, pages={1537–1550} }
 @article{borneman_rose_simons_2016, title={Off-road vehicles affect nesting behaviour and reproductive success of American Oystercatchers Haematopus palliatus}, volume={158}, ISSN={0019-1019}, url={http://dx.doi.org/10.1111/ibi.12358}, DOI={10.1111/ibi.12358}, abstractNote={As human populations and associated development increase, interactions between humans and wildlife are occurring with greater frequency. The effects of these interactions, particularly on species whose populations are declining, are of great interest to ecologists, conservationists, land managers and natural resource policy‐makers. The American Oystercatcher Haematopus palliatus, a species of conservation concern in the USA, nests on coastal beaches subject to various forms of anthropogenic disturbance, including aircraft overflights, off‐road vehicles and pedestrians. This study assessed the effects of these human disturbances on the incubation behaviour and reproductive success of nesting American Oystercatchers at Cape Lookout National Seashore, on the Atlantic coast of the USA. We expanded on‐going monitoring of Oystercatchers at Cape Lookout National Seashore by supplementing periodic visual observations with continuous 24‐h video and audio recording at nests. Aircraft overflights were not associated with changes in Oystercatcher incubation behaviour, and we found no evidence that aircraft overflights influenced Oystercatcher reproductive success. However, Oystercatchers were on their nests significantly less often during off‐road vehicle and pedestrian events than they were during control periods before the events, and an increase in the number of off‐road vehicles passing a nest during incubation was consistently associated with significant reductions in daily nest survival (6% decrease in daily nest survival for a one‐vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.94; 95% confidence interval (CI) 0.90, 0.98) and hatching success (12% decrease in hatching success for a one‐vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.88; 95% CI 0.76, 0.97). Management of vehicles and pedestrians in areas of Oystercatcher breeding is important for the conservation of American Oystercatchers.}, number={2}, journal={Ibis}, publisher={Wiley}, author={Borneman, Tracy E. and Rose, Eli T. and Simons, Theodore R.}, year={2016}, month={Apr}, pages={261–278} }
 @article{parsons_simons_pollock_stoskopf_stocking_o'connell_2015, title={Camera traps and mark-resight models: The value of ancillary data for evaluating assumptions}, volume={79}, ISSN={0022-541X}, url={http://dx.doi.org/10.1002/jwmg.931}, DOI={10.1002/jwmg.931}, abstractNote={ABSTRACT}, number={7}, journal={The Journal of Wildlife Management}, publisher={Wiley}, author={Parsons, Arielle W. and Simons, Theodore R. and Pollock, Kenneth H. and Stoskopf, Michael K. and Stocking, Jessica J. and O'connell, Allan F., Jr.}, year={2015}, month={Aug}, pages={1163–1172} }
 @article{schulte_simons_2015, title={Factors affecting the reproductive success of American Oystercatchers (Haematopus palliatus) on the Outer Banks of North Carolina}, volume={43}, number={1}, journal={Marine Ornithology}, publisher={Pacific Seabird Group}, author={Schulte, S.A. and Simons, T.R.}, year={2015}, pages={37–47} }
 @article{miller_bailey_grant_mcclintock_weir_simons_2015, title={Performance of species occurrence estimators when basic assumptions are not met: a test using field data where true occupancy status is known}, volume={6}, ISSN={2041-210X}, url={http://dx.doi.org/10.1111/2041-210X.12342}, DOI={10.1111/2041-210x.12342}, abstractNote={Summary}, number={5}, journal={Methods in Ecology and Evolution}, publisher={Wiley}, author={Miller, David A. W. and Bailey, Larissa L. and Grant, Evan H. Campbell and McClintock, Brett T. and Weir, Linda A. and Simons, Theodore R.}, editor={Gimenez, OlivierEditor}, year={2015}, month={Mar}, pages={557–565} }
 @article{hostetter_gardner_schweitzer_boettcher_wilke_addison_swilling_pollock_simons_2015, title={Repeated count surveys help standardize multi-agency estimates of American Oystercatcher (Haematopus palliatus) abundance}, volume={117}, ISSN={0010-5422 1938-5129}, url={http://dx.doi.org/10.1650/CONDOR-14-185.1}, DOI={10.1650/condor-14-185.1}, abstractNote={ABSTRACT The extensive breeding range of many shorebird species can make integration of survey data problematic at regional spatial scales. We evaluated the effectiveness of standardized repeated count surveys coordinated across 8 agencies to estimate the abundance of American Oystercatcher (Haematopus palliatus) breeding pairs in the southeastern United States. Breeding season surveys were conducted across coastal North Carolina (90 plots) and the Eastern Shore of Virginia (3 plots). Plots were visited on 1–5 occasions during April–June 2013. N-mixture models were used to estimate abundance and detection probability in relation to survey date, tide stage, plot size, and plot location (coastal bay vs. barrier island). The estimated abundance of oystercatchers in the surveyed area was 1,048 individuals (95% credible interval: 851–1,408) and 470 pairs (384–637), substantially higher than estimates that did not account for detection probability (maximum counts of 674 individuals and 316 pairs). Detection probability was influenced by a quadratic function of survey date, and increased from mid-April (~0.60) to mid-May (~0.80), then remained relatively constant through June. Detection probability was also higher during high tide than during low, rising, or falling tides. Abundance estimates from N-mixture models were validated at 13 plots by exhaustive productivity studies (2–5 surveys wk−1). Intensive productivity studies identified 78 breeding pairs across 13 productivity plots while the N-mixture model abundance estimate was 74 pairs (62–119) using only 1–5 replicated surveys season−1. Our results indicate that standardized replicated count surveys coordinated across multiple agencies and conducted during a relatively short time window (closure assumption) provide tremendous potential to meet both agency-level (e.g., state) and regional-level (e.g., flyway) objectives in large-scale shorebird monitoring programs.}, number={3}, journal={The Condor}, publisher={Oxford University Press (OUP)}, author={Hostetter, Nathan J. and Gardner, Beth and Schweitzer, Sara H. and Boettcher, Ruth and Wilke, Alexandra L. and Addison, Lindsay and Swilling, William R. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2015}, month={Aug}, pages={354–363} }
 @article{clay_lesterhuis_schulte_brown_reynolds_simons_2014, title={A global assessment of the conservation status of the American Oystercatcher (Haematopus palliatus)}, volume={20}, journal={International Wader Studies}, author={Clay, R.P. and Lesterhuis, A.J. and Schulte, S. and Brown, S. and Reynolds, D. and Simons, T.R.}, year={2014}, pages={62–82} }
 @article{keller_xie_buchwalter_franzreb_simons_2014, title={Mercury bioaccumulation in Southern Appalachian birds, assessed through feather concentrations}, volume={23}, ISSN={0963-9292 1573-3017}, url={http://dx.doi.org/10.1007/S10646-013-1174-6}, DOI={10.1007/s10646-013-1174-6}, abstractNote={Mercury contamination in wildlife has rarely been studied in the Southern Appalachians despite high deposition rates in the region. From 2006 to 2008 we sampled feathers from 458 birds representing 32 species in the Southern Appalachians for total mercury and stable isotope δ (15)N. Mercury concentrations (mean ± SE) averaged 0.46 ± 0.02 μg g(-1) (range 0.01-3.74 μg g(-1)). Twelve of 32 species had individuals (7 % of all birds sampled) with mercury concentrations higher than 1 μg g(-1). Mercury concentrations were 17 % higher in juveniles compared to adults (n = 454). In adults, invertivores has higher mercury levels compared to omnivores. Mercury was highest at low-elevation sites near water, however mercury was detected in all birds, including those in the high elevations (1,000-2,000 m). Relative trophic position, calculated from δ (15)N, ranged from 2.13 to 4.87 across all birds. We fitted linear mixed-effects models to the data separately for juveniles and year-round resident adults. In adults, mercury concentrations were 2.4 times higher in invertivores compared to omnivores. Trophic position was the main effect explaining mercury levels in juveniles, with an estimated 0.18 ± 0.08 μg g(-1) increase in feather mercury for each one unit rise in trophic position. Our research demonstrates that mercury is biomagnifying in birds within this terrestrial mountainous system, and further research is warranted for animals foraging at higher trophic levels, particularly those associated with aquatic environments downslope from montane areas receiving high mercury deposition.}, number={2}, journal={Ecotoxicology}, publisher={Springer Science and Business Media LLC}, author={Keller, Rebecca Hylton and Xie, Lingtian and Buchwalter, David B. and Franzreb, Kathleen E. and Simons, Theodore R.}, year={2014}, month={Jan}, pages={304–316} }
 @article{borneman_rose_simons_2014, title={Minimal changes in heart rate of incubating American Oystercatchers (Haematopus palliatus) in response to human activity}, volume={116}, ISSN={["1938-5129"]}, DOI={10.1650/condor-14-48.1}, abstractNote={ABSTRACT An organism's heart rate is commonly used as an indicator of physiological stress due to environmental stimuli. We used heart rate to monitor the physiological response of American Oystercatchers (Haematopus palliatus) to human activity in their nesting environment. We placed artificial eggs with embedded microphones in 42 oystercatcher nests to record the heart rate of incubating oystercatchers continuously for up to 27 days. We used continuous video and audio recordings collected simultaneously at the nests to relate physiological response of birds (heart rate) to various types of human activity. We observed military and civilian aircraft, off-road vehicles, and pedestrians around nests. With the exception of high-speed, low-altitude military overflights, we found little evidence that oystercatcher heart rates were influenced by most types of human activity. The low-altitude flights were the only human activity to significantly increase average heart rates of incubating oystercatchers (12% above baseline). Although statistically significant, we do not consider the increase in heart rate during high-speed, low-altitude military overflights to be of biological significance. This noninvasive technique may be appropriate for other studies of stress in nesting birds.}, number={3}, journal={CONDOR}, author={Borneman, Tracy E. and Rose, Eli T. and Simons, Theodore R.}, year={2014}, month={Aug}, pages={493–503} }
 @article{sollmann_gardner_parsons_stocking_mcclintock_simons_pollock_allan f. o'connell_2013, title={A spatial mark-resight model augmented with telemetry data}, volume={94}, ISSN={["1939-9170"]}, DOI={10.1890/12-1256.1}, abstractNote={Abundance and population density are fundamental pieces of information for population ecology and species conservation, but they are difficult to estimate for rare and elusive species. Mark–resight models are popular for estimating population abundance because they are less invasive and expensive than traditional mark–recapture. However, density estimation using mark–resight is difficult because the area sampled must be explicitly defined, historically using ad hoc approaches. We developed a spatial mark–resight model for estimating population density that combines spatial resighting data and telemetry data. Incorporating telemetry data allows us to inform model parameters related to movement and individual location. Our model also allows <100% individual identification of marked individuals. We implemented the model in a Bayesian framework, using a custom‐made Metropolis‐within‐Gibbs Markov chain Monte Carlo algorithm. As an example, we applied this model to a mark–resight study of raccoons (Procyon lotor) on South Core Banks, a barrier island in Cape Lookout National Seashore, North Carolina, USA. We estimated a population of 186.71 ± 14.81 individuals, which translated to a density of 8.29 ± 0.66 individuals/km2 (mean ± SD). The model presented here will have widespread utility in future applications, especially for species that are not naturally marked.}, number={3}, journal={ECOLOGY}, author={Sollmann, Rahel and Gardner, Beth and Parsons, Arielle W. and Stocking, Jessica J. and McClintock, Brett T. and Simons, Theodore R. and Pollock, Kenneth H. and Allan F. O'Connell}, year={2013}, month={Mar}, pages={553–559} }
 @article{parsons_simons_o'connell_stoskopf_2013, title={Demographics, diet, movements, and survival of an isolated, unmanaged raccoon Procyon lotor (Procyonidae, Carnivora) population on the Outer Banks of North Carolina}, volume={77}, DOI={10.1515/mammalia-2011-0138}, abstractNote={Abstract Raccoons (Procyon lotor) are highly adaptable meso-carnivores that inhabit many environments, including the Atlantic barrier islands, where their role as predators of declining, beach-nesting bird and turtle species is of particular interest. Population models that improve our understanding of predator-prey dynamics are receiving increasing attention in the literature; however, their effective application requires site-specific information on population parameters. We studied an unharvested raccoon population on the Outer Banks of North Carolina and evaluated spatial and seasonal differences in a number of population/demographic factors of raccoons inhabiting areas of high and low human activity. Raccoons denned and foraged primarily in salt marsh habitats but shifted their movements in response to changes in seasonal resource conditions. The population was skewed toward older animals and exhibited delayed breeding, typical of populations at high density with few sources of mortality. Diet and movement analysis indicated shorebird and turtle predation was attributed to a small number of individual raccoons. Although seasonal resources appeared adequate to sustain a high population density of raccoons, poor body condition and low recruitment suggested a population near carrying capacity.}, number={1}, journal={Mammalia}, author={Parsons, A. W. and Simons, T. R. and O'Connell, A. F. and Stoskopf, M. K.}, year={2013}, pages={21–30} }
 @article{simons_lee_haney_2013, title={Diablotin Pterodroma hasitata: A biography of the endangered Black-capped Petrel}, volume={41}, journal={Marine Ornithology}, publisher={Pacific Seabird Group}, author={Simons, T.R. and Lee, D.S. and Haney, J.C.}, year={2013}, pages={1–43} }
 @article{becker_moorman_deperno_simons_2013, title={Quantifiable Long-term Monitoring on Parks and Nature Preserves}, volume={12}, ISSN={["1938-5412"]}, DOI={10.1656/058.012.0208}, abstractNote={Abstract 
 Herpetofauna have declined globally, and monitoring is a useful approach to document local and long-term changes. However, monitoring efforts often fail to account for detectability or follow standardized protocols. We performed a case study at Hemlock Bluffs Nature Preserve in Cary, NC to model occupancy of focal species and demonstrate a replicable long-term protocol useful to parks and nature preserves. From March 2010 to 2011, we documented occupancy of Ambystoma opacum (Marbled Salamander), Plethodon cinereus (Red-backed Salamander), Carphophis amoenus (Eastern Worm Snake), and Diadophis punctatus (Ringneck Snake) at coverboard sites and estimated breeding female Ambystoma maculatum (Spotted Salamander) abundance via dependent double-observer egg-mass counts in ephemeral pools. Temperature influenced detection of both Marbled and Red-backed Salamanders. Based on egg-mass data, we estimated Spotted Salamander abundance to be between 21 and 44 breeding females. We detected 43 of 53 previously documented herpetofauna species. Our approach demonstrates a monitoring protocol that accounts for factors that influence species detection and is replicable by parks or nature preserves with limited resources.}, number={2}, journal={SOUTHEASTERN NATURALIST}, author={Becker, Sharon and Moorman, Christopher and DePerno, Christopher and Simons, Theodore}, year={2013}, month={Jun}, pages={339–352} }
 @article{miller_weir_mcclintock_grant_bailey_simons_2012, title={Experimental investigation of false positive errors in auditory species occurrence surveys}, volume={22}, DOI={10.1890/1051-0761-22.5.1665}, abstractNote={Ecological ApplicationsVolume 22, Issue 5 p. 1665-1674 Article Experimental investigation of false positive errors in auditory species occurrence surveys David A. W. Miller, Corresponding Author David A. W. Miller davidmiller@usgs.gov United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, Maryland 20708 USAE-mail: davidmiller@usgs.govSearch for more papers by this authorLinda A. Weir, Linda A. Weir United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, Maryland 20708 USASearch for more papers by this authorBrett T. McClintock, Brett T. McClintock National Marine Mammal Laboratory, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, Washington 98115 USASearch for more papers by this authorEvan H. Campbell Grant, Evan H. Campbell Grant United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, Maryland 20708 USASearch for more papers by this authorLarissa L. Bailey, Larissa L. Bailey Colorado State University, Department of Fish, Wildlife and Conservation Biology, Fort Collins, Colorado 80523 USASearch for more papers by this authorTheodore R. Simons, Theodore R. Simons United States Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit, Department of Biology, North Carolina State University, Raleigh, North Carolina 27695 USASearch for more papers by this author David A. W. Miller, Corresponding Author David A. W. Miller davidmiller@usgs.gov United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, Maryland 20708 USAE-mail: davidmiller@usgs.govSearch for more papers by this authorLinda A. Weir, Linda A. Weir United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, Maryland 20708 USASearch for more papers by this authorBrett T. McClintock, Brett T. McClintock National Marine Mammal Laboratory, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, Washington 98115 USASearch for more papers by this authorEvan H. Campbell Grant, Evan H. Campbell Grant United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, Maryland 20708 USASearch for more papers by this authorLarissa L. Bailey, Larissa L. Bailey Colorado State University, Department of Fish, Wildlife and Conservation Biology, Fort Collins, Colorado 80523 USASearch for more papers by this authorTheodore R. Simons, Theodore R. Simons United States Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit, Department of Biology, North Carolina State University, Raleigh, North Carolina 27695 USASearch for more papers by this author First published: 01 July 2012 https://doi.org/10.1890/11-2129.1Citations: 67 Corresponding Editor: D. Brunton. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract False positive errors are a significant component of many ecological data sets, which in combination with false negative errors, can lead to severe biases in conclusions about ecological systems. We present results of a field experiment where observers recorded observations for known combinations of electronically broadcast calling anurans under conditions mimicking field surveys to determine species occurrence. Our objectives were to characterize false positive error probabilities for auditory methods based on a large number of observers, to determine if targeted instruction could be used to reduce false positive error rates, and to establish useful predictors of among-observer and among-species differences in error rates. We recruited 31 observers, ranging in abilities from novice to expert, who recorded detections for 12 species during 180 calling trials (66 960 total observations). All observers made multiple false positive errors, and on average 8.1% of recorded detections in the experiment were false positive errors. Additional instruction had only minor effects on error rates. After instruction, false positive error probabilities decreased by 16% for treatment individuals compared to controls with broad confidence interval overlap of 0 (95% CI: −46 to 30%). This coincided with an increase in false negative errors due to the treatment (26%; −3 to 61%). Differences among observers in false positive and in false negative error rates were best predicted by scores from an online test and a self-assessment of observer ability completed prior to the field experiment. In contrast, years of experience conducting call surveys was a weak predictor of error rates. False positive errors were also more common for species that were played more frequently but were not related to the dominant spectral frequency of the call. Our results corroborate other work that demonstrates false positives are a significant component of species occurrence data collected by auditory methods. Instructing observers to only report detections they are completely certain are correct is not sufficient to eliminate errors. As a result, analytical methods that account for false positive errors will be needed, and independent testing of observer ability is a useful predictor for among-observer variation in observation error rates. Citing Literature Supporting Information Filename Description https://dx.doi.org/10.6084/m9.figshare.c.3295511 Research data pertaining to this article is located at figshare.com: Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Volume22, Issue5July 2012Pages 1665-1674 RelatedInformation}, number={5}, journal={Ecological Applications}, author={Miller, D. A. W. and Weir, L. A. and McClintock, B. T. and Grant, E. H. C. and Bailey, L. L. and Simons, T. R.}, year={2012}, pages={1665–1674} }
 @inproceedings{simmerman_wang_osborne_shook_huang_godsoe_simons_2012, title={Exploring similarities among many species distributions}, ISBN={9781450316026}, url={http://dx.doi.org/10.1145/2335755.2335835}, DOI={10.1145/2335755.2335835}, abstractNote={Collecting species presence data and then building models to predict species distribution has been long practiced in the field of ecology for the purpose of improving our understanding of species relationships with each other and with the environment. Due to limitations of computing power as well as limited means of using modeling software on HPC facilities, past species distribution studies have been unable to fully explore diverse data sets. We build a system that can, for the first time to our knowledge, leverage HPC to support effective exploration of species similarities in distribution as well as their dependencies on common environmental conditions. Our system can also compute and reveal uncertainties in the modeling results enabling domain experts to make informed judgments about the data. Our work was motivated by and centered around data collection efforts within the Great Smoky Mountains National Park that date back to the 1940s. Our findings present new research opportunities in ecology and produce actionable field-work items for biodiversity management personnel to include in their planning of daily management activities.}, booktitle={Proceedings of the 1st Conference of the Extreme Science and Engineering Discovery Environment on Bridging from the eXtreme to the campus and beyond - XSEDE '12}, publisher={ACM Press}, author={Simmerman, Scott and Wang, Jingyuan and Osborne, James and Shook, Kimberly and Huang, Jian and Godsoe, William and Simons, Theodore}, year={2012} }
 @book{simons_stocking_2011, place={Raleigh, NC}, title={American Oystercatcher Conservation Initiative in North Carolina: 2010 Report}, institution={US Geological Survey North Carolina Cooperative Fish and Wildlife Research Unit, Department of Biology, North Carolina State University,}, author={Simons, T.R. and Stocking, J.J.}, year={2011} }
 @book{simons_borneman_2011, title={Effects of Military Jet Overflights on American Oystercatcher Breeding Behavior and Productivity at Cape Lookout National Seashore}, journal={2011 Annual Report to the U.S. Marine Corps}, author={Simons, T.R. and Borneman, T.}, year={2011} }
 @article{riddle_pollock_simons_2010, title={AN UNRECONCILED DOUBLE-OBSERVER METHOD FOR ESTIMATING DETECTION PROBABILITY AND ABUNDANCE}, volume={127}, ISSN={["1938-4254"]}, DOI={10.1525/auk.2010.09118}, abstractNote={ABSTRACT. Multiple-observer point-count methods allow estimation of detection probability and have some advantages over other point-count methods. We introduce the unreconciled double-observer method, an independent double-observer method that does not require observers to match or otherwise reconcile individual observations. The modeling of the counts uses the repeated-counts model (Royle 2004). We compared estimates of detection probability and abundance from the unreconciled double-observer method with estimates from the traditional independent double-observer method (which requires matching of individual animals) using field-simulated bird-point-count data. The unreconciled double-observer method provided point estimates of detection probability and abundance that were essentially identical to the results of the independent double-observer method, even though much less effort was required to collect data with the unreconciled method. Estimates of detection probability from the unreconciled double-observer method were usually less precise—and estimates of abundance always less precise—than those from the independent double-observer method, because there is less information available in the unreconciled double-observer approach. We also evaluated the unreconciled double-observer method on 12 Breeding Bird Survey (BBS) routes. The unreconciled double-observer method provided estimates of route-level abundance for most routes and for most of the 20 species we considered. We believe that this method has potential for established bird-monitoring programs such as the BBS because no changes in historical data-collection methods are required other than collecting data simultaneously using two or more observers.}, number={4}, journal={AUK}, author={Riddle, Jason D. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2010}, month={Oct}, pages={841–849} }
 @book{simons_stocking_2010, place={Washington, DC}, title={American Oystercatcher Conservation Initiative – North Carolina}, institution={National Park Service}, author={Simons, T.R. and Stocking, J.J.}, year={2010} }
 @article{tarr_simons_pollock_2010, title={An Experimental Assessment of Vehicle Disturbance Effects on Migratory Shorebirds}, volume={74}, ISSN={["0022-541X"]}, DOI={10.2193/2009-105}, abstractNote={ABSTRACT Off‐road vehicle (ORV) traffic is one of several forms of disturbance thought to affect shorebirds at migration stopover sites. Attempts to measure disturbance effects on shorebird habitat use and behavior at stopover sites are difficult because ORV disturbance is frequently confounded with habitat and environmental factors. We used a before‐after‐control‐impact experimental design to isolate effects of vehicle disturbance from shorebird responses to environmental and habitat factors. We manipulated disturbance levels within beach closures along South Core Banks, North Carolina, USA, and measured changes in shorebird abundance and location, as well as the activity of one focal species, the sanderling (Calidris alba), within paired control and impact plots. We applied a discrete treatment level of one flee‐response‐inducing event every 10 minutes on impact plots. We found that disturbance reduced total shorebird and black‐bellied plover (Pluvialis squatarola) abundance and reduced relative use of microhabitat zones above the swash zone (wet sand and dry sand) by sanderlings, black‐bellied plovers, willets (Tringa semipalmata), and total shorebirds. Sanderlings and total shorebirds increased use of the swash zone in response to vehicle disturbance. Disturbance reduced use of study plots by sanderlings for resting and increased sanderling activity, but we did not detect an effect of vehicle disturbance on sanderling foraging activity. We provide the first estimates of how a discrete level of disturbance affects shorebird distributions among ocean beach microhabitats. Our findings provide a standard to which managers can compare frequency and intensity of disturbance events at other shorebird stopover and roosting sites and indicate that limiting disturbance will contribute to use of a site by migratory shorebirds.}, number={8}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Tarr, Nathan M. and Simons, Theodore R. and Pollock, Kenneth H.}, year={2010}, month={Nov}, pages={1776–1783} }
 @inbook{sanders_dunn_fitzpatrick_carlton_pogue_parker_simons_2010, place={Boca Raton, Florida}, title={Diverse Elevational Diversity Gradients in Great Smoky Mountains National Park, U.S.A}, booktitle={Data Mining for Global Trends in Mountain Biodiversity}, publisher={CRC Press}, author={Sanders, N.J. and Dunn, R.R. and Fitzpatrick, M.C. and Carlton, C.E. and Pogue, M.R. and Parker, C.R. and Simons, T.R.}, editor={Spehn, E.M. and Korner, C.Editors}, year={2010}, pages={75–87} }
 @article{riddle_mordecai_pollock_simons_2010, title={EFFECTS OF PRIOR DETECTIONS ON ESTIMATES OF DETECTION PROBABILITY, ABUNDANCE, AND OCCUPANCY}, volume={127}, ISSN={["1938-4254"]}, DOI={10.1525/auk.2009.09062}, abstractNote={ABSTRACT. 
 Survey methods that account for detection probability often require repeated detections of individual birds or repeated visits to a site to conduct counts or collect presence-absence data. Initial encounters with individual species or individuals of a species could influence detection probabilities for subsequent encounters. For example, observers may be more likely to redetect a species or individual once they are aware of the presence of that species or individual at a particular site. Not accounting for these effects could result in biased estimators of detection probability, abundance, and occupancy. We tested for effects of prior detections in three data sets that differed dramatically by species, geographic location, and method of counting birds. We found strong support (AIC weights from 83% to 100%) for models that allowed for the effects of prior detections. These models produced estimates of detection probability, abundance, and occupancy that differed substantially from those produced by models that ignored the effects of prior detections. We discuss the consequences of the effects of prior detections on estimation for several sampling methods and provide recommendations for avoiding these effects through survey design or by modeling them when they cannot be avoided.}, number={1}, journal={AUK}, author={Riddle, Jason D. and Mordecai, Rua S. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2010}, month={Jan}, pages={94–99} }
 @book{simons_borneman_2010, place={Washington, DC}, title={Effects of Military Jet Overflights on American Oystercatcher Breeding Behavior and Productivity at Cape Lookout National Seashore}, institution={U.S. Marine Corps}, author={Simons, T.R. and Borneman, T.}, year={2010} }
 @article{mcclintock_bailey_pollock_simons_2010, title={Experimental Investigation of Observation Error in Anuran Call Surveys}, volume={74}, ISSN={["1937-2817"]}, DOI={10.2193/2009-321}, abstractNote={ABSTRACT Occupancy models that account for imperfect detection are often used to monitor anuran and songbird species occurrence. However, presence—absence data arising from auditory detections may be more prone to observation error (e.g., false‐positive detections) than are sampling approaches utilizing physical captures or sightings of individuals. We conducted realistic, replicated field experiments using a remote broadcasting system to simulate simple anuran call surveys and to investigate potential factors affecting observation error in these studies. Distance, time, ambient noise, and observer abilities were the most important factors explaining false‐negative detections. Distance and observer ability were the best overall predictors of false‐positive errors, but ambient noise and competing species also affected error rates for some species. False‐positive errors made up 5% of all positive detections, with individual observers exhibiting false‐positive rates between 0.5% and 14%. Previous research suggests false‐positive errors of these magnitudes would induce substantial positive biases in standard estimators of species occurrence, and we recommend practices to mitigate for false positives when developing occupancy monitoring protocols that rely on auditory detections. These recommendations include additional observer training, limiting the number of target species, and establishing distance and ambient noise thresholds during surveys.}, number={8}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Mcclintock, Brett T. and Bailey, Larissa L. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2010}, month={Nov}, pages={1882–1893} }
 @article{martin_kendall_runge_simons_waldstein_schulte_converse_smith_pinion_rikard_et al._2010, title={Optimal control of native predators}, volume={143}, ISSN={["1873-2917"]}, DOI={10.1016/j.biocon.2010.04.023}, abstractNote={We apply decision theory in a structured decision-making framework to evaluate how control of raccoons (Procyon lotor), a native predator, can promote the conservation of a declining population of American Oystercatchers (Haematopus palliatus) on the Outer Banks of North Carolina. Our management objective was to maintain Oystercatcher productivity above a level deemed necessary for population recovery while minimizing raccoon removal. We evaluated several scenarios including no raccoon removal, and applied an adaptive optimization algorithm to account for parameter uncertainty. We show how adaptive optimization can be used to account for uncertainties about how raccoon control may affect Oystercatcher productivity. Adaptive management can reduce this type of uncertainty and is particularly well suited for addressing controversial management issues such as native predator control. The case study also offers several insights that may be relevant to the optimal control of other native predators. First, we found that stage-specific removal policies (e.g., yearling versus adult raccoon removals) were most efficient if the reproductive values among stage classes were very different. Second, we found that the optimal control of raccoons would result in higher Oystercatcher productivity than the minimum levels recommended for this species. Third, we found that removing more raccoons initially minimized the total number of removals necessary to meet long term management objectives. Finally, if for logistical reasons managers cannot sustain a removal program by removing a minimum number of raccoons annually, managers may run the risk of creating an ecological trap for Oystercatchers.}, number={7}, journal={BIOLOGICAL CONSERVATION}, author={Martin, Julien and Kendall, William L. and Runge, Michael C. and Simons, Theodore R. and Waldstein, Arielle H. and Schulte, Shiloh A. and Converse, Sarah. J. and Smith, Graham W. and Pinion, Timothy and Rikard, Michael and et al.}, year={2010}, month={Jul}, pages={1751–1758} }
 @article{stanislav_pollock_simons_alldredge_2010, title={Separation of Availability and Perception Processes for Aural Detection in Avian Point Counts: a Combined Multiple-Observer and Time-of-Detection Approach}, volume={5}, ISSN={1712-6568}, url={http://dx.doi.org/10.5751/ace-00372-050103}, DOI={10.5751/ace-00372-050103}, abstractNote={In this study, we review various methods of estimating detection probabilities for avian point counts: distance sampling, multiple observer methods, and recently proposed time-of-detection methods. Both distance and multiple observer methods require the sometimes unrealistic assumption that all birds in the population sing during the count interval. We provide a general model of detection where the total probability of detection is made up of the probability of a bird singing, i.e., availability, and the probability of detecting a bird, conditional on its having sung. We show that the time-of-detection method provides an estimate of the total probability, whereas combining the time-of-detection method with a multiple observer method enables estimation of the two components of the detection process separately. Our approach is shown to be a special case of Pollock's robust capture-recapture design where the probability that a bird does not sing is equivalent to the probability that an animal is a temporary emigrant. We estimate Hooded Warbler and Ovenbird population size, through maximum likelihood estimation, using experimentally simulated field data for which the true population sizes were known. The method performs well when singing rates and detection probabilities are high, and when observers are able to accurately localize individual birds. Population sizes are underestimated when there is heterogeneity of singing rates among individual birds, especially when singing rates are close to zero. Despite the additional expense and the potential for counting and matching errors, we encourage field ornithologists to consider using this combined method in their field studies to better understand the detection process, and to obtain better abundance estimates.}, number={1}, journal={Avian Conservation and Ecology}, publisher={Resilience Alliance, Inc.}, author={Stanislav, Stephen J. and Pollock, Kenneth H. and Simons, Theodore R. and Alldredge, Mathew W.}, year={2010} }
 @article{stringer_stoskopf_simons_o'connell_waldstein_2010, title={Ultrasonic Measurement of Body Fat as a Means of Assessing Body Condition in Free-Ranging Raccoons (Procyon lotor)}, volume={2010}, ISSN={1687-8477 1687-8485}, url={http://dx.doi.org/10.1155/2010/972380}, DOI={10.1155/2010/972380}, abstractNote={Assessment of body condition of free-ranging animals is important when evaluating population health and fitness. The following study used body condition scoring, ultrasound, and dissected physical measurement to assess fat stores in free-ranging raccoons (Procyon lotor). Measurements were taken of subcutaneous fat at interscapular, thoracolumbar, and lumbosacral paraspinal and ventral midline sites. These measurements were examined in relationship to body condition scores and body weight. The ultrasound technique accurately measured the subcutaneous fat of raccoons when compared to dissected physical measurement and yielded data that strongly correlated with both body condition score and body weight, with the ventral midline measurement most strongly correlated. This noninvasive method may be useful in conjunction with body condition score and body weight when assessing the nutritional status of raccoons and potentially other small carnivore species.}, journal={International Journal of Zoology}, publisher={Hindawi Limited}, author={Stringer, Elizabeth M. and Stoskopf, Michael K. and Simons, Theodore and O'Connell, Allan F. and Waldstein, Arielle}, year={2010}, pages={1–6} }
 @article{mcclintock_bailey_pollock_simons_2010, title={Unmodeled observation error induces bias when inferring patterns and dynamics of species occurrence via aural detections}, volume={91}, ISSN={["0012-9658"]}, DOI={10.1890/09-1287.1}, abstractNote={The recent surge in the development and application of species occurrence models has been associated with an acknowledgment among ecologists that species are detected imperfectly due to observation error. Standard models now allow unbiased estimation of occupancy probability when false negative detections occur, but this is conditional on no false positive detections and sufficient incorporation of explanatory variables for the false negative detection process. These assumptions are likely reasonable in many circumstances, but there is mounting evidence that false positive errors and detection probability heterogeneity may be much more prevalent in studies relying on auditory cues for species detection (e.g., songbird or calling amphibian surveys). We used field survey data from a simulated calling anuran system of known occupancy state to investigate the biases induced by these errors in dynamic models of species occurrence. Despite the participation of expert observers in simplified field conditions, both false positive errors and site detection probability heterogeneity were extensive for most species in the survey. We found that even low levels of false positive errors, constituting as little as 1% of all detections, can cause severe overestimation of site occupancy, colonization, and local extinction probabilities. Further, unmodeled detection probability heterogeneity induced substantial underestimation of occupancy and overestimation of colonization and local extinction probabilities. Completely spurious relationships between species occurrence and explanatory variables were also found. Such misleading inferences would likely have deleterious implications for conservation and management programs. We contend that all forms of observation error, including false positive errors and heterogeneous detection probabilities, must be incorporated into the estimation framework to facilitate reliable inferences about occupancy and its associated vital rate parameters.}, number={8}, journal={ECOLOGY}, author={McClintock, Brett T. and Bailey, Larissa L. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2010}, month={Aug}, pages={2446–2454} }
 @inbook{simons_pollock_wettroth_alldredge_pacifici_brewster_2009, title={Sources of Measurement Error, Misclassification Error, and Bias in Auditory Avian Point Count Data}, ISBN={9780387781501 9780387781518}, url={http://dx.doi.org/10.1007/978-0-387-78151-8_10}, DOI={10.1007/978-0-387-78151-8_10}, booktitle={Modeling Demographic Processes In Marked Populations}, publisher={Springer US}, author={Simons, Theodore R. and Pollock, Kenneth H. and Wettroth, John M. and Alldredge, Mathew W. and Pacifici, Krishna and Brewster, Jerome}, year={2009}, pages={237–254} }
 @article{brewster_simons_2009, title={Testing the importance of auditory detections in avian point counts}, volume={80}, ISSN={["1557-9263"]}, DOI={10.1111/j.1557-9263.2009.00220.x}, abstractNote={Recent advances in the methods used to estimate detection probability during point counts suggest that the detection process is shaped by the types of cues available to observers. For example, models of the detection process based on distance-sampling or time-of-detection methods may yield different results for auditory versus visual cues because of differences in the factors that affect the transmission of these cues from a bird to an observer or differences in an observer's ability to localize cues. Previous studies suggest that auditory detections predominate in forested habitats, but it is not clear how often observers hear birds prior to detecting them visually. We hypothesized that auditory cues might be even more important than previously reported, so we conducted an experiment in a forested habitat in North Carolina that allowed us to better separate auditory and visual detections. Three teams of three observers each performed simultaneous 3-min unlimited-radius point counts at 30 points in a mixed-hardwood forest. One team member could see, but not hear birds, one could hear, but not see, and the third was nonhandicapped. Of the total number of birds detected, 2.9% were detected by deafened observers, 75.1% by blinded observers, and 78.2% by nonhandicapped observers. Detections by blinded and nonhandicapped observers were the same only 54% of the time. Our results suggest that the detection of birds in forest habitats is almost entirely by auditory cues. Because many factors affect the probability that observers will detect auditory cues, the accuracy and precision of avian point count estimates are likely lower than assumed by most field ornithologists.}, number={2}, journal={JOURNAL OF FIELD ORNITHOLOGY}, author={Brewster, Jerome P. and Simons, Theodore R.}, year={2009}, month={Jun}, pages={178–182} }
 @article{alldredge_pacifici_simons_pollock_2008, title={A novel field evaluation of the effectiveness of distance and independent observer sampling to estimate aural avian detection probabilities}, volume={45}, ISSN={0021-8901 1365-2664}, url={http://dx.doi.org/10.1111/j.1365-2664.2008.01517.x}, DOI={10.1111/j.1365-2664.2008.01517.x}, abstractNote={Summary 1. The validation of field sampling techniques is a concern for applied ecologists due to the strong model assumptions implicit in all methods. Computer simulations make replication easy, but they do not give insights into how much bias occurs in real populations. Testing sampling methods on populations of known size can establish directly how well estimators perform, but such populations are very hard to find, and replicate, and they may have unusual attributes. 2. We present a field validation of distance and double-observer methods of estimating detection probabilities on aural avian point counts. Our research is relevant to conservation agencies worldwide who design thousands of avian monitoring programmes based primarily on auditory point counts. The programmes are a critical component in the management of many avian species. 3. Our validation used a simulation system which mimics birds calling in a field environment. The system allowed us to vary singing rate, species, distance, the complexity of points, and other factors. 4. Distance methods performed poorly, primarily due to large localization errors, and estimates did not improve for simplified points. 5. For the double-observer method, two pairs of observers tended to underestimate true population size, while the third pair tended to double-count birds which overestimated the population. Detection probabilities were always higher and population estimates lower when observers subjectively matched birds compared to an objective rule and showed a slight negative bias and good precision. A simplified 45-degree matching rule did not improve the performance of double-observer estimates which had a slight positive bias and much lower precision. Double-observer estimates did improve on the simplified points. 6. Synthesis and applications . We encourage ecologists working with sampling methods to develop similar methods of working with simulated populations through use of technology. Our simulated field evaluation has demonstrated the difficulty of accurately estimating population size when limited to aural detections. Problems are related to limitations in the ability of observers to localize sound, estimate distance, and accurately identify birds during a count. Other sources of error identified are the effects of observers, singing rate, singing orientation and background noise.}, number={5}, journal={Journal of Applied Ecology}, publisher={Wiley}, author={Alldredge, Mathew W. and Pacifici, Krishna and Simons, Theodore R. and Pollock, Kenneth H.}, year={2008}, month={Oct}, pages={1349–1356} }
 @book{simons_schulte_2008, place={Washington, DC}, title={American Oystercatcher (Haematopus palliatus) research and monitoring in North Carolina}, institution={National Park Service, U.S. Fish and Wildlife Service, and the National Audubon Society}, author={Simons, T.R. and Schulte, S.}, year={2008} }
 @article{webster_pollock_simons_2008, title={Bayesian spatial modeling of data from avian point count surveys}, volume={13}, ISSN={["1537-2693"]}, DOI={10.1198/108571108X311563}, abstractNote={We present a unified framework for modeling bird survey data collected at spatially replicated survey sites in the form of repeated counts or detection history counts, through which we model spatial dependence in bird density and variation in detection probabilities due to changes in covariates across the landscape. The models have a complex hierarchical structure that makes them suited to Bayesian analysis using Markov chain Monte Carlo (MCMC) algorithms. For computational efficiency, we use a form of conditional autogressive model for modeling spatial dependence. We apply the models to survey data for two bird species in the Great Smoky Mountains National Park. The algorithms converge well for the more abundant and easily detected of the two species, but some simplification of the spatial model is required for convergence for the second species. We show how these methods lead to maps of estimated relative density which are an improvement over those that would follow from past approaches that ignored spatial dependence. This work also highlights the importance of good survey design for bird species mapping studies.}, number={2}, journal={JOURNAL OF AGRICULTURAL BIOLOGICAL AND ENVIRONMENTAL STATISTICS}, author={Webster, Raymond A. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2008}, month={Jun}, pages={121–139} }
 @article{pacifici_simons_pollock_2008, title={EFFECTS OF VEGETATION AND BACKGROUND NOISE ON THE DETECTION PROCESS IN AUDITORY AVIAN POINT-COUNT SURVEYS}, volume={125}, ISSN={0004-8038 1938-4254}, url={http://dx.doi.org/10.1525/auk.2008.07078}, DOI={10.1525/auk.2008.07078}, abstractNote={Abstract We used a bird-song simulation system to experimentally assess the effects of habitat, vegetation structure, and background noise on detection probability in aural avian point counts. We simulated bird songs of seven species in two habitats (mixed pine–hardwood forest and deciduous forest) and two leaf conditions (leaves on and leaves off) with two levels of background noise (~40 dB and ~50 dB). Estimated detection probabilities varied greatly among species, and complex interactions among all the factors existed. Background noise and the presence of leaves on trees decreased detection probabilities, and estimated detection probabilities were higher in mixed pine–hardwood forest than in deciduous forest. At 100 m, average estimated detection probabilities ranged from 0 to 1 and were lowest for the Black-and-white Warbler (Mniotilta varia) and highest for the Brown Thrasher (Toxostoma rufum). Simulations of expected counts, based on the best logistic model, indicated that observers detect between 3% (for the worst observer, least detectable species, with leaves on the trees and added background noise in the deciduous forest) and 99% (for the best observer, most detectable species, with no leaves on the trees and no added background noise in the mixed forest) of the total count. The large variation in expected counts illustrates the importance of estimating detection probabilities directly. The large differences in detection probabilities among species suggest that tailoring monitoring protocols to specific species of interest may produce better estimates than a single protocol applied to a wide range of species.}, number={3}, journal={The Auk}, publisher={Oxford University Press (OUP)}, author={Pacifici, Krishna and Simons, Theodore R. and Pollock, Kenneth H.}, year={2008}, month={Jul}, pages={600–607} }
 @article{pacific_simons_pollock_2008, title={EFFECTS OF VEGETATION AND BACKGROUND NOISE ON THE DETECTION PROCESS IN AUDITORY AVIAN POINT-COUNT SURVEYS (vol 125, pg 500, 2008)}, volume={125}, ISSN={["0004-8038"]}, DOI={10.1525/auk.2008.111008}, number={4}, journal={AUK}, author={Pacific, Krishna and Simons, Theodore R. and Pollock, Kenneth H.}, year={2008}, month={Oct}, pages={998–998} }
 @book{simons_hylton_2008, place={Washington, DC}, title={Effects of Atmospheric Pollution on High Elevation Fauna in the Great Smoky Mountains National Park}, institution={National Park Service and the U.S. Geological Survey}, author={Simons, T.R. and Hylton, R.}, year={2008} }
 @book{simons_tarr_2008, place={Washington, DC}, title={Fall shorebird migration and ORV disturbance at Cape Lookout National Seashore}, institution={National Park Service}, author={Simons, T.R. and Tarr, N.}, year={2008} }
 @book{simons_waldstein_o'connell_2008, place={Washington, DC}, title={Raccoon (Procyon lotor) Ecology at Cape Lookout National Seashore, North Carolina}, institution={National Park Service}, author={Simons, T.R. and Waldstein, A. and O'Connell, A.}, year={2008} }
 @article{simons_pollock_wettroth_alldredge_pacifici_brewster_2008, title={Sources of measurement error, misclassification error, and bias in auditory avian point count data}, journal={The All-Bird Bulletin}, author={Simons, T.R. and Pollock, K.H. and Wettroth, J.M. and Alldredge, M.W. and Pacifici, K. and Brewster, J.}, year={2008}, month={Mar}, pages={2–3} }
 @article{alldredge_simons_pollock_pacifici_2007, title={A Field Evaluation of the Time-of-Detection Method to Estimate Population Size and Density for Aural Avian Point Counts}, volume={2}, ISSN={1712-6568}, url={http://dx.doi.org/10.5751/ace-00205-020213}, DOI={10.5751/ace-00205-020213}, abstractNote={The time-of-detection method for aural avian point counts is a new method of estimating abundance, allowing for uncertain probability of detection. The method has been specifically designed to allow for variation in singing rates of birds. It involves dividing the time interval of the point count into several subintervals and recording the detection history of the subintervals when each bird sings. The method can be viewed as generating data equivalent to closed capture–recapture information. The method is different from the distance and multiple-observer methods in that it is not required that all the birds sing during the point count. As this method is new and there is some concern as to how well individual birds can be followed, we carried out a field test of the method using simulated known populations of singing birds, using a laptop computer to send signals to audio stations distributed around a point. The system mimics actual aural avian point counts, but also allows us to know the size and spatial distribution of the populations we are sampling. Fifty 8-min point counts (broken into four 2-min intervals) using eight species of birds were simulated. Singing rate of an individual bird of a species was simulated following a Markovian process (singing bouts followed by periods of silence), which we felt was more realistic than a truly random process. The main emphasis of our paper is to compare results from species singing at (high and low) homogenous rates per interval with those singing at (high and low) heterogeneous rates. Population size was estimated accurately for the species simulated, with a high homogeneous probability of singing. Populations of simulated species with lower but homogeneous singing probabilities were somewhat underestimated. Populations of species simulated with heterogeneous singing probabilities were substantially underestimated. Underestimation was caused by both the very low detection probabilities of all distant individuals and by individuals with low singing rates also having very low detection probabilities. RESUME. La methode fondee sur le temps de detection utilisee dans le contexte des points d’ecoute represente une nouvelle approche pour estimer l’abondance des oiseaux en tenant compte de la probabilite incertaine de detection. Cette methode a ete specialement concue pour tenir compte du taux variable de chant observe chez les oiseaux. Elle consiste a diviser l’intervalle de temps passe a un point d’ecoute en sous-intervalles et de noter l’historique de detection des sous-intervalles ou chaque individu est detecte. Les donnees obtenues par cette methode peuvent etre considerees comme etant equivalentes a celles obtenues par la capture-recapture dans une population fermee. La methode differe des approches fondees sur la distance et les observateurs multiples du fait qu’elle n’exige pas que tous les individus chantent durant le point d’ecoute. Puisque cette methode est nouvelle et qu’il existe une incertitude quant a la capacite de suivre les individus, nous avons effectue une evaluation sur le terrain de sa precision en utilisant des simulations sur des populations connues d’oiseaux chanteurs a l’aide d’un ordinateur portatif qui envoyait des signaux a des stations audio distribuees autour du point d’ecoute. Ce systeme imite un veritable point Colorado Division of Wildlife, Cooperative Fish and Wildlife Research Unit, Dept of Zoology, North Carolina State University Avian Conservation and Ecology Ecologie et conservation des oiseaux 2(2): 13 http://www.ace-eco.org/vol2/iss2/art13/ d’ecoute tout en permettant de connaitre l’effectif et la distribution des populations echantillonnees. Cinquante points d’ecoute de 8 min (separes en intervalles de 2 min) ont ete simules pour huit especes d’oiseaux. Le taux de vocalisation de chaque individu a ete simule a l’aide d’une chaine de Markov (periodes de chant suivies de periodes de silence), ce qui nous semblait plus realiste qu’un processus purement aleatoire. L’objectif principal de notre article etait de comparer les resultats pour des especes chantant a une frequence homogene (elevee ou faible) par intervalle avec d’autres especes chantant a des frequences heterogenes (elevees ou faibles). L’effectif de la population a ete estime precisement pour les especes simulees ayant une frequence de vocalisation homogene et elevee. L’effectif des populations des especes simulees presentant une frequence de vocalisation faible mais homogene a ete legerement sous-estime. Dans les cas des especes chantant a des frequences heterogenes, les populations etaient fortement sousestimees. La sous-estimation etait causee a la fois par la faible probabilite de detection de tous les individus eloignes et des individus chantant a des frequences faibles.}, number={2}, journal={Avian Conservation and Ecology}, publisher={Resilience Alliance, Inc.}, author={Alldredge, Mathew W. and Simons, Theodore R. and Pollock, Kenneth H. and Pacifici, Krishna}, year={2007}, pages={13} }
 @article{alldredge_simons_pollock_2007, title={A field evaluation of distance measurement error in auditory avian point count surveys}, volume={71}, ISSN={["1937-2817"]}, DOI={10.2193/2006-161}, abstractNote={ABSTRACT Detection distance is an important and common auxiliary variable measured during avian point count surveys. Distance data are used to determine the area sampled and to model the detection process using distance sampling theory. In densely forested habitats, visual detections of birds are rare, and most estimates of detection distance are based on auditory cues. Distance sampling theory assumes detection distances are measured accurately, but empirical validation of this assumption for auditory detections is lacking. We used a song playback system to simulate avian point counts with known distances in a forested habitat to determine the error structure of distance estimates based on auditory detections. We conducted field evaluations with 6 experienced observers both before and after distance estimation training. We conducted additional studies to determine the effect of height and speaker orientation (toward or away from observers) on distance estimation error. Distance estimation errors for all evaluations were substantial, although training reduced errors and bias in distance estimates by approximately 15%. Measurement errors showed a nonlinear relationship to distance. Our results suggest observers were not able to differentiate distances beyond 65 m. The height from which we played songs had no effect on distance estimation errors in this habitat. The orientation of the song source did have a large effect on distance estimation errors; observers generally doubled their distance estimates for songs played away from them compared with distance estimates for songs played directly toward them. These findings, which we based on realistic field conditions, suggest measures of uncertainty in distance estimates to auditory detections are substantially higher than assumed by most researchers. This means aural point count estimates of avian abundance based on distance methods deserve careful scrutiny because they are likely biased.}, number={8}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Alldredge, Mathew W. and Simons, Theodore R. and Pollock, Kenneth H.}, year={2007}, month={Nov}, pages={2759–2766} }
 @book{simons_schulte_cordes_lyons_golder_2007, title={American Oystercatcher (Haematopus palliatus) research and monitoring in North Carolina.}, institution={U.S. Fish and Wildlife Service, and the National Audubon Society}, author={Simons, T.R. and Schulte, S. and Cordes, J. and Lyons, M. and Golder, W.}, year={2007} }
 @book{simons_hylton_2007, place={Washington, DC}, title={Assessing the Effects of Atmospheric Pollution on High Elevation Bird and Snail Communities in the Southern Appalachians}, institution={National Park Service and the U.S. Geological Survey}, author={Simons, T.R. and Hylton, R.}, year={2007} }
 @article{simons_alldredge_pollock_wettroth_2007, title={Experimental analysis of the auditory detection process on avian point counts}, volume={124}, ISSN={["1938-4254"]}, DOI={10.1642/0004-8038(2007)124[986:EAOTAD]2.0.CO;2}, abstractNote={Abstract We have developed a system for simulating the conditions of avian surveys in which birds are identified by sound. The system uses a laptop computer to control a set of amplified MP3 players placed at known locations around a survey point. The system can realistically simulate a known population of songbirds under a range of factors that affect detection probabilities. The goals of our research are to describe the sources and range of variability affecting point-count estimates and to find applications of sampling theory and methodologies that produce practical improvements in the quality of bird-census data. Initial experiments in an open field showed that, on average, observers tend to undercount birds on unlimited-radius counts, though the proportion of birds counted by individual observers ranged from 81% to 132% of the actual total. In contrast to the unlimited-radius counts, when data were truncated at a 50-m radius around the point, observers overestimated the total population by 17% to 122%. Results also illustrate how detection distances decline and identification errors increase with increasing levels of ambient noise. Overall, the proportion of birds heard by observers decreased by 28 ± 4.7% under breezy conditions, 41 ± 5.2% with the presence of additional background birds, and 42 ± 3.4% with the addition of 10 dB of white noise. These findings illustrate some of the inherent difficulties in interpreting avian abundance estimates based on auditory detections, and why estimates that do not account for variations in detection probability will not withstand critical scrutiny. Análisis Experimentales del Proceso de Detección Auditiva en Puntos de Conteo de Aves}, number={3}, journal={AUK}, author={Simons, Theodore R. and Alldredge, Mathew W. and Pollock, Kenneth H. and Wettroth, John M.}, year={2007}, month={Jul}, pages={986–999} }
 @article{alldredge_simons_pollock_2007, title={Factors affecting aural detections of songbirds}, volume={17}, ISSN={["1939-5582"]}, DOI={10.1890/06-0685}, abstractNote={Many factors affect the number of birds detected on point count surveys of breeding songbirds. The magnitude and importance of these factors are not well understood. We used a bird song simulation system to quantify the effects of detection distance, singing rate, species differences, and observer differences on detection probabilities of birds detected by ear. We simulated 40 point counts consisting of 10 birds per count for five primary species (Black-and-white Warbler Mniotilta varia, Black-throated Blue Warbler Dendroica caerulescens, Black-throated Green Warbler Dendroica virens, Hooded Warbler Wilsonia citrina, and Ovenbird Seiurus aurocapillus) over a range of 15 distances (34-143 m). Songs were played at low (two songs per count) and high (13-21 songs per count) singing rates. Detection probabilities averaged across observers ranged from 0.60 (Black-and-white Warbler) to 0.83 (Hooded Warbler) at the high singing rate and 0.41 (Black-and-white Warbler) to 0.67 (Hooded Warbler) at the low singing rate. Logistic regression analyses indicated that species, singing rate, distance, and observer were all significant factors affecting detection probabilities. Singing rate x species and singing rate X distance interactions were also significant. Simulations of expected counts, based on the best logistic model, indicated that observers detected between 19% (for the worst observer, lowest singing rate, and least detectable species) and 65% (for the best observer, highest singing rate, and most detectable species) of the true population. Detection probabilities on actual point count surveys are likely to vary even more because many sources of variability were controlled in our experiments. These findings strongly support the importance of adjusting measures of avian diversity or abundance from auditory point counts with direct estimates of detection probability.}, number={3}, journal={ECOLOGICAL APPLICATIONS}, author={Alldredge, Mathew W. and Simons, Theodore R. and Pollock, Kenneth H.}, year={2007}, month={Apr}, pages={948–955} }
 @article{podolsky_simons_collazo_2007, title={Modeling population growth of the ovenbird (Seiurus aurocapilla) in the southern appalachians}, volume={124}, ISSN={["0004-8038"]}, DOI={10.1642/0004-8038(2007)124[1359:MPGOTO]2.0.CO;2}, abstractNote={Abstract Studies of source-sink dynamics are often prompted by concerns about negative population trends. Estimates of population trajectories are usually based on assumptions about survival rates and empirical measures of fecundity. Most models ignore the influence of the rates of renesting and multiple brooding. We used the Ovenbird (Seiurus aurocapilla) as a model Neotropical migratory songbird species to investigate the relative effects of annual female survival and components of annual fecundity on population growth rates. We applied productivity data from a three- year field study and data from Hann (1937) to several models of annual fecundity to examine the sensitivity of lambda to variations in annual female survival and the likelihood of renesting and double-brooding. Our simulations illustrate the importance of incorporating estimates of annual survival and rates of additional breeding attempts in songbird population models because population growth rates are quite sensitive to variations in these parameters. Lambda is especially sensitive to survival estimates and changes with them at the same order of magnitude. Whenever feasible, female survival and probabilities of additional breeding attempts should be estimated by direct methods. The indirect methods used in our study (annual female survival estimated from the age ratio of breeding females, and rates of renesting and double- brooding determined from the timing of reproduction) probably underestimated these parameters. Modelado del Crecimiento Poblacional de Seiurus aurocapilla en el Sur de los Apalaches}, number={4}, journal={AUK}, author={Podolsky, Andrei L. and Simons, Theodore R. and Collazo, Jaime A.}, year={2007}, month={Oct}, pages={1359–1372} }
 @article{alldredge_pollock_simons_shriner_2007, title={Multiple-species analysis of point count data: a more parsimonious modelling framework}, volume={44}, ISSN={["1365-2664"]}, DOI={10.1111/j.1365-2664.2006.01271.x}, abstractNote={Summary}, number={2}, journal={JOURNAL OF APPLIED ECOLOGY}, author={Alldredge, Mathew W. and Pollock, Kenneth H. and Simons, Theodore R. and Shriner, Susan A.}, year={2007}, month={Apr}, pages={281–290} }
 @book{simons_tarr_2007, place={Washington, DC}, title={The effects of vehicle traffic on migrating shorebirds at Cape Lookout National Seashore}, institution={National Park Service}, author={Simons, T.R. and Tarr, N.}, year={2007} }
 @article{alldredge_pollock_simons_collazo_shriner_2007, title={Time-of-detection method for estimating abundance from point-count surveys}, volume={124}, ISSN={["1938-4254"]}, DOI={10.1642/0004-8038(2007)124[653:TMFEAF]2.0.CO;2}, abstractNote={Abstract Point-count surveys are often used to collect data on the abundance and distribution of birds, generally as an index of relative abundance. Valid comparison of these indices assumes that the detection process is comparable over space and time. These restrictive assumptions can be eliminated by estimating detection probabilities directly. We generalize a recently proposed removal model for estimating detection probabilities using a time-of-detection approach, which can account for more sources of variation in point-count data. This method is specifically designed to account for variation in detection probabilities associated with singing rates of birds. Our model accounts for both availability bias and detection bias by modeling the combined probability that a bird sings during the count, and the probability that it is detected given that it sings. The model requires dividing the count into several intervals and recording detections of individual birds in each interval. We develop maximum-likelihood estimators for this approach and provide a full suite of models based on capture-recapture models, including covariate models. We present two examples of this method: one for four species of songbirds surveyed in Great Smoky Mountains National Park using three unequal intervals, and one for the Pearly-eyed Thrasher (Margarops fuscatus) surveyed in Puerto Rico using four equal intervals. Models incorporating individual heterogeneity were selected for all data sets using information-theoretic model-selection techniques. Detection probabilities varied among count-time intervals, which suggests that birds may be responding to observers. We recommend applying this method to surveys with four or more equal intervals to reduce assumptions and to take full advantage of standard capture-recapture software. The time-of-detection approach provides a better understanding of the detection process, especially when singing rates of individual birds affect detection probabilities. Estimación de la Abundancia en Puntos de Conteo Mediante el Método del Tiempo de Detección}, number={2}, journal={AUK}, author={Alldredge, Mathew W. and Pollock, Kenneth H. and Simons, Theodore R. and Collazo, Jaime A. and Shriner, Susan A.}, year={2007}, month={Apr}, pages={653–664} }
 @book{simons_schulte_mcgowan_cordes_lyons_golder_2006, place={Washington, DC}, title={American Oystercatcher (Haematopus palliatus) research and monitoring in North Carolina.}, institution={National Park Service, U.S Fish and Wildlife Service, and the National Audubon Society}, author={Simons, T.R. and Schulte, S. and McGowan, C. and Cordes, J. and Lyons, M. and Golder, W.}, year={2006} }
 @book{simons_hylton_2006, place={Washington, DC}, title={Assessment of Black-capped Chickadees as a Model Species for a Calcium Limitation Study in the Southern Appalachians}, institution={National Park Service and the U.S. Geological Survey}, author={Simons, T.R. and Hylton, R.}, year={2006} }
 @article{simons_shriner_farnsworth_2006, title={Comparison of breeding bird and vegetation communities in primary and secondary forests of Great Smoky Mountains National Park}, volume={129}, ISSN={["1873-2917"]}, DOI={10.1016/j.biocon.2005.10.044}, abstractNote={We compared breeding bird communities and vegetation characteristics at paired point locations in primary (undisturbed) and mature secondary forest (70–100 years old) sites in Great Smoky Mountains National Park, USA to understand how sites logged prior to creation of the park compare to undisturbed sites following 70 years of protection from human disturbance. We found that bird and vegetation communities are currently similar, but retain some differences in species composition. Rank abundance curves for primary and secondary forest bird communities showed very similar patterns of species dominance. Species composition was also similar on the two sites which shared 24 of the 25 most frequently recorded species. Nonetheless, comparisons of density estimates derived from distance sampling showed three bird species were more abundant on primary forest sites and that one bird species was significantly more abundant on secondary forest sites. Notably, comparisons based on raw counts (unadjusted for potential differences in detectability) produced somewhat different results. Analyses of vegetation samples for the paired sites also showed relative similarity, but with some differences between primary and secondary forests. Primary forest sites had more large trees (trees greater than 50 cm diameter at breast height) and late successional species. Primary forest sites had a denser tall shrub layer while secondary forest sites had a denser canopy layer. Nonetheless, tree species richness, basal area of live trees and number of standing snags did not differ between primary and secondary forest sites. Results indicate that breeding bird communities on sites within the park that were logged commercially 70 years ago are currently quite similar to bird communities on sites with no history of human disturbance. Similarities between the bird communities on previously disturbed and undisturbed sites in Great Smoky Mountains National Park may exceed those on more fragmented landscapes because large patches of primary forest, adjacent to commercially logged sites, remained in the park when it was established in 1935. These patches of primary forest may have served as source areas for commercially logged sites.}, number={3}, journal={BIOLOGICAL CONSERVATION}, author={Simons, TR and Shriner, SA and Farnsworth, GL}, year={2006}, month={May}, pages={302–311} }
 @article{mcgowan_simons_2006, title={Effects of human recreation on the incubation behavior of American Oystercatchers}, volume={118}, ISSN={["1938-5447"]}, DOI={10.1676/05-084.1}, abstractNote={Abstract Human recreational disturbance and its effects on wildlife demographics and behavior is an increasingly important area of research. We monitored the nesting success of American Oystercatchers (Haematopus palliatus) in coastal North Carolina in 2002 and 2003. We also used video monitoring at nests to measure the response of incubating birds to human recreation. We counted the number of trips per hour made by adult birds to and from the nest, and we calculated the percent time that adults spent incubating. We asked whether human recreational activities (truck, all-terrain vehicle ;obATV;cb, and pedestrian traffic) were correlated with parental behavioral patterns. Eleven a priori models of nest survival and behavioral covariates were evaluated using Akaike's Information Criterion (AIC) to see whether incubation behavior influenced nest survival. Factors associated with birds leaving their nests (n = 548) included ATV traffic (25%), truck traffic (17%), pedestrian traffic (4%), aggression with neighboring oystercatchers or paired birds exchanging incubation duties (26%), airplane traffic (1%) and unknown factors (29%). ATV traffic was positively associated with the rate of trips to and away from the nest (β1 = 0.749, P < 0.001) and negatively correlated with percent time spent incubating (β1 = −0.037, P = 0.025). Other forms of human recreation apparently had little effect on incubation behaviors. Nest survival models incorporating the frequency of trips by adults to and from the nest, and the percentage of time adults spent incubating, were somewhat supported in the AIC analyses. A low frequency of trips to and from the nest and, counter to expectations, low percent time spent incubating were associated with higher daily nest survival rates. These data suggest that changes in incubation behavior might be one mechanism by which human recreation affects the reproductive success of American Oystercatchers.}, number={4}, journal={WILSON JOURNAL OF ORNITHOLOGY}, author={McGowan, Conor P. and Simons, Theodore R.}, year={2006}, month={Dec}, pages={485–493} }
 @book{simons_pollock_2006, title={Estimating detection probabilities for community assessment and population monitoring}, institution={USGS Status and Trends Program}, author={Simons, T.R. and Pollock, K.J.}, year={2006} }
 @article{alldredge_pollock_simons_2006, title={Estimating detection probabilities from multiple-observer point counts}, volume={123}, ISSN={["1938-4254"]}, DOI={10.1642/0004-8038(2006)123[1172:EDPFMP]2.0.CO;2}, abstractNote={Abstract Point counts are commonly used to obtain indices of bird population abundance. We present an independent-observer point-count method, a generalization of the dependent-observer approach, based on closed-population capture- recapture methods. The approach can incorporate individual covariates, such as detection distance, to account for individual differences in detection probabilities associated with measurable sources of variation. We demonstrate a negative bias in two-observer estimates by comparing abundance estimates from two- and four- observer point counts. Models incorporating data from four independent observers were capable of accounting for this bias. Modeling individual bird differences in detection probabilities produced abundance estimates 15–21% higher than models that did not account for individual differences, in four out of five data sets analyzed. Although independent-observer methods are expensive and impractical for large- scale applications, we believe they can provide important insights into the sources and degree of perception bias (i.e., probability of detecting an individual, given that it is available for detection) in avian point-count estimates. Therefore, they may be useful in a two-stage sampling framework to calibrate larger surveys based on single-observer estimates. Estimación de Probabilidades de Detección a Partir de Conteos en Puntos Hechos por Varios Observadores}, number={4}, journal={AUK}, author={Alldredge, Mathew W. and Pollock, Kenneth H. and Simons, Theodore R.}, year={2006}, month={Oct}, pages={1172–1182} }
 @book{simons_tarr_2006, place={Washington, DC}, title={Measuring the effect of off-road vehicles on beach birds at Cape Lookout National Seashore}, institution={National Park Service}, author={Simons, T.R. and Tarr, N.}, year={2006} }
 @article{mcgowan_simons_golder_cordes_2005, title={A comparison of American Oystercatcher reproductive success on barrier beach and river island habitats in coastal North Carolina}, volume={28}, ISSN={["1938-5390"]}, DOI={10.1675/1524-4695(2005)028[0150:ACOAOR]2.0.CO;2}, abstractNote={Abstract American Oystercatcher (Haematopus palliatus) numbers along the east coast of the United States are declining in some areas and expanding in others. Researchers have suggested that movement from traditional barrier beach habitats to novel inland habitats and coastal marshes may explain some of these changes, but few studies have documented oystercatcher reproductive success in non-traditional habitats. This study compares the reproductive success of the American Oystercatcher on three river islands in the lower Cape Fear River of North Carolina with that of birds nesting on barrier island beach habitat of Cape Lookout National Seashore. There were 17.6 times more oystercatcher breeding pairs per kilometer on the river island habitat than barrier beach habitat. The Mayfield estimate of daily nest content survival was 0.97 (S.E. ± 0.0039) on river islands, significantly higher than 0.92 (S.E. ± 0.0059) on barrier islands. The primary identifiable cause of nest failure on the river islands was flooding while the main cause of nest failure on the barrier islands was mammalian predation. Fledging success was equally low at both study sites. Only 0.19 chicks fledged per pair in 2002, and 0.21 chicks fledged per pair in 2003 on the river islands and 0.14 chicks fledged per pair in 2002 and 0.20 chicks fledged per pair in 2003 on the barrier islands. Many questions are still unanswered and more research is needed to fully understand the causes of chick mortality and the functional significance of non-traditional nesting habitats for the American Oystercatcher in the eastern United States.}, number={2}, journal={WATERBIRDS}, author={McGowan, CP and Simons, TR and Golder, W and Cordes, J}, year={2005}, month={Jun}, pages={150–155} }
 @article{mcgowan_simons_2005, title={A method for trapping breeding adult American Oystercatchers}, volume={76}, ISSN={["1557-9263"]}, DOI={10.1648/0273-8570-76.1.46}, abstractNote={Abstract We present an efficient and effective method for trapping adult, breeding American Oystercatchers (Haematopus palliatus) that minimizes disturbance to nesting birds and the risk of trapping injuries. We used a remote controlled mechanical decoy to lure territorial adults to a leg-hold noose-mat trap. We trapped 25 birds over two seasons and were successful on 54% of our trapping attempts in 2003. We only trapped birds before the breeding season or between nesting attempts to reduce nest-site disturbance.}, number={1}, journal={JOURNAL OF FIELD ORNITHOLOGY}, author={McGowan, CP and Simons, TR}, year={2005}, pages={46–49} }
 @book{simons_pollock_2005, title={Estimating detection probabilities for community assessment and population monitoring}, institution={USGS Status and Trends Program}, author={Simons, T.R. and Pollock, K.J.}, year={2005} }
 @inbook{hyde_simons_2005, place={Berkeley}, title={Monitoring Salamander Populations in Great Smoky Mountains National Park}, booktitle={Amphibian Declines: the conservation and status of United States Species}, publisher={University of California Press}, author={Hyde, E.J. and Simons, T.R.}, editor={Lannoo, M.J.Editor}, year={2005} }
 @misc{farnsworth_simons_2005, title={Relationship between Mayfield nest-survival estimates and seasonal fecundity: A cautionary reply.}, volume={122}, ISSN={["0004-8038"]}, DOI={10.1642/0004-8038(2005)122[1000:rbmnea]2.0.co;2}, number={3}, journal={AUK}, author={Farnsworth, GL and Simons, TR}, year={2005}, month={Jul}, pages={1000–1001} }
 @article{mcgowan_schulte_simons_2005, title={Resightings of marked American Oystercatchers banded as chicks}, volume={117}, ISSN={["0043-5643"]}, DOI={10.1676/04-112.1}, abstractNote={Abstract Since 2000, we have been banding American Oystercatcher (Haematopus palliatus) chicks at Cape Lookout and Cape Hatteras national seashores as part of a long-term demographic study. Between 2000 and 2002, we banded 23 chicks. We report on resightings of eight chicks that returned to the Outer Banks of North Carolina in the summers of 2003 and 2004. These are the first records of American Oystercatcher chicks resighted near their natal areas in their 2nd and 3rd years. The 3-year-old birds appeared to be paired and acted territorial, whereas the 2nd-year birds were observed alone or in groups and did not exhibit territorial behavior. Our observations suggest that the American Oystercatcher's life history is similar to that of the Eurasian Oystercatcher (Haematopus ostralegus).}, number={4}, journal={WILSON BULLETIN}, author={McGowan, CP and Schulte, SA and Simons, TR}, year={2005}, month={Dec}, pages={382–385} }
 @book{farnsworth_nichols_sauer_fancy_pollock_shriner_simons_2005, title={Statistical approaches to the analysis of point count data: a little extra information can go a long way}, volume={PSW-GTR-191}, number={PSW-GTR-191}, institution={USDA Forest Service}, author={Farnsworth, G.L. and Nichols, J.D. and Sauer, J.R. and Fancy, S.T. and Pollock, K.H. and Shriner, S.A. and Simons, T.R.}, year={2005}, pages={736–743} }
 @book{moore_woodrey_buler_woltmann_simons_2005, place={Albany, CA}, title={Understanding the stopover of migratory birds: a scale dependent approach.}, volume={2}, number={PSW-GTR-191}, journal={Bird Conservation Implementation and Integration in the Americas: Proceedings of the Third International Partners in Flight Conference}, institution={U.S. Dept. of Agriculture, Forest Service, Pacific Southwest Research Station}, author={Moore, F.R. and Woodrey, M.S. and Buler, J.J. and Woltmann, S. and Simons, T.R.}, editor={Ralph, C. John and Rich, Terrell D.Editors}, year={2005}, pages={684–689} }
 @article{podolsky_simons_collazo_2004, title={A method of food supplementation for ground-foraging insectivorous songbirds}, volume={75}, ISSN={["1557-9263"]}, DOI={10.1648/0273-8570-75.3.296}, abstractNote={Abstract Food supplementation can be an important experimental technique in studies of avian reproductive ecology, energetics, and parental care. We developed a method of food supplementation suitable for ground-foraging insectivorous passerines and tested it on Ovenbird (Seiurus aurocapilla) and Wood Thrushes (Hylocichla mustelina). We provided mealworms at feeding stations made of plastic transparency film covered with a thin layer of green moss. Feeding stations were placed on the ground or on logs or boulders in the vicinity of nests. Direct and indirect evidence suggested that 92% of breeding Ovenbirds and 79% of breeding Wood Thrushes used supplemental food. The impact of non-target consumers was not significant: they were observed eating mealworms at approximately one-third of our food-supplemented nests. However, diurnal non-target consumers were only detected on a single occasion for each species, and nocturnal consumers fed on small amounts of mealworms left after daytime feeding experiments. This method proved very effective for Ovenbirds and Wood Thrushes, and it may be applicable to other ground-foraging insectivorous passerines.}, number={3}, journal={JOURNAL OF FIELD ORNITHOLOGY}, author={Podolsky, AL and Simons, TR and Collazo, JA}, year={2004}, pages={296–302} }
 @article{bailey_simons_pollock_2004, title={Comparing population size estimators for plethodontid salamanders}, volume={38}, ISSN={["1937-2418"]}, DOI={10.1670/194-03A}, abstractNote={Abstract Despite concern over amphibian declines, few studies estimate absolute abundances because of logistic and economic constraints and previously poor estimator performance. Two estimation approaches recommended for amphibian studies are mark-recapture and depletion (or removal) sampling. We compared abundance estimation via various mark-recapture and depletion methods, using data from a three-year study of terrestrial salamanders in Great Smoky Mountains National Park. Our results indicate that short-term closed-population, robust design, and depletion methods estimate surface population of salamanders (i.e., those near the surface and available for capture during a given sampling occasion). In longer duration studies, temporary emigration violates assumptions of both open- and closed-population mark-recapture estimation models. However, if the temporary emigration is completely random, these models should yield unbiased estimates of the total population (superpopulation) of salamanders in the sampled area. We recommend using Pollock's robust design in mark-recapture studies because of its flexibility to incorporate variation in capture probabilities and to estimate temporary emigration probabilities.}, number={3}, journal={JOURNAL OF HERPETOLOGY}, author={Bailey, LL and Simons, TR and Pollock, KH}, year={2004}, month={Sep}, pages={370–380} }
 @book{simons_pollock_2004, place={Washington, DC}, title={Estimating detection probabilities for community assessment and population monitoring}, institution={USGS Status and Trends Program}, author={Simons, T.R. and Pollock, K.J.}, year={2004} }
 @article{bailey_simons_pollock_2004, title={Estimating detection probability parameters for plethodon salamanders using the robust capture-recapture design}, volume={68}, number={1}, journal={Journal of Wildlife Management}, author={Bailey, L. L. and Simons, T. R. and Pollock, K. H.}, year={2004}, pages={13-} }
 @article{bailey_simons_pollock_2004, title={Estimating site occupancy and species detection probability parameters for terrestrial salamanders}, volume={14}, ISSN={["1051-0761"]}, DOI={10.1890/03-5012}, abstractNote={Recent, worldwide amphibian declines have highlighted a need for more extensive and rigorous monitoring programs to document species occurrence and detect population change. Abundance estimation methods, such as mark–recapture, are often expensive and impractical for large‐scale or long‐term amphibian monitoring. We apply a new method to estimate proportion of area occupied using detection/nondetection data from a terrestrial salamander system in Great Smoky Mountains National Park. Estimated species‐specific detection probabilities were all <1 and varied among seven species and four sampling methods. Time (i.e., sampling occasion) and four large‐scale habitat characteristics (previous disturbance history, vegetation type, elevation, and stream presence) were important covariates in estimates of both proportion of area occupied and detection probability. All sampling methods were consistent in their ability to identify important covariates for each salamander species. We believe proportion of area occupied represents a useful state variable for large‐scale monitoring programs. However, our results emphasize the importance of estimating detection and occupancy probabilities rather than using an unadjusted proportion of sites where species are observed where actual occupancy probabilities are confounded with detection probabilities. Estimated detection probabilities accommodate variations in sampling effort; thus comparisons of occupancy probabilities are possible among studies with different sampling protocols.}, number={3}, journal={ECOLOGICAL APPLICATIONS}, author={Bailey, LL and Simons, TR and Pollock, KH}, year={2004}, month={Jun}, pages={692–702} }
 @inbook{simons_moore_gauthreaux_2004, series={Studies in Avian Biology}, title={Mist netting trans-Gulf migrants at coastal stopover sites: the influence of spatial and temporal variability on capture data}, booktitle={The use of mist nets to monitor bird populations}, author={Simons, T.R. and Moore, F.R. and Gauthreaux, S.A.}, editor={Ralph, C.J. and Dunn, E.H.Editors}, year={2004}, pages={135–143}, collection={Studies in Avian Biology} }
 @inbook{pollock_marsh_bailey_farnsworth_simons_alldredge_2004, title={Separating components of detection probability in population abundance estimation: An overview with diverse examples}, booktitle={Sampling rare or elusive species: Concepts, designs, and techniques for estimating population parameters}, publisher={Island Press}, author={Pollock, K.H. and Marsh, H.H. and Bailey, L.L. and Farnsworth, G.L. and Simons, T.R. and Alldredge, M.W.}, editor={Thompson, WilliamEditor}, year={2004}, pages={43–58} }
 @article{bailey_simons_pollock_2004, title={Spatial and temporal variation in detection probability of plethodon salamanders using the robust capture-recapture design}, volume={68}, ISSN={["0022-541X"]}, DOI={10.2193/0022-541X(2004)068[0014:SATVID]2.0.CO;2}, abstractNote={Abstract Recent worldwide amphibian declines have highlighted a need for long-term, large-scale monitoring programs. Scientific or management objectives, appropriate spatial sampling, and detectability all must be considered when designing monitoring programs (Yoccoz et al. 2001). The ability to establish meaningful monitoring programs currently is compromised by a lack of information about amphibian detection probabilities. We used Pollock's robust design and capture–recapture models that included temporary emigration to test a priori hypotheses about spatial and temporal variation in salamander detection probability parameters for populations found in Great Smoky Mountains National Park (Tennessee/North Carolina), USA. We explored the effects of 3 large-scale habitat characteristics (disturbance history, elevation, vegetation type) and found that vegetation type and elevation were correlated with detection probabilities. Vegetation type was an important covariant in estimates of temporary emigration, conditional capture probability, and surface population size. Contrasts that isolated elevation effects were significant for all detection probability parameters except recapture probability, despite our small elevational range (330 m). When detection probability parameters have the potential to vary over time and space, investigators should develop monitoring designs that permit the estimation of detection probabilities.}, number={1}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Bailey, LL and Simons, TR and Pollock, KH}, year={2004}, month={Jan}, pages={14–24} }
 @book{simons_mcgowan_cordes_lyons_golder_2003, place={Washington, DC}, title={American Oystercatcher (Haematopus paliatus) research and monitoring in North Carolina.}, institution={National Park Service and the US Fish and Wildlife Service}, author={Simons, T.R. and McGowan, C. and Cordes, J. and Lyons, M. and Golder, W.}, year={2003} }
 @book{simons_pollock_2003, title={Estimating detection probabilities for community assessment and population monitoring}, institution={USGS Status and Trends Program}, author={Simons, T.R. and Pollock, K.J.}, year={2003} }
 @inbook{shriner_simons_farnsworth_2002, place={Washington, DC}, title={A GIS-based habitat model for Wood Thrush, Hylocichla mustelina, in Great Smoky Mountains National Park.}, ISBN={9781559637879}, booktitle={Predicting Species Occurrences: Issues of Scale and Accuracy}, publisher={Island Press}, author={Shriner, S.A. and Simons, T.R. and Farnsworth, George L.}, editor={Scott, J.M.Editor}, year={2002}, pages={529–536} }
 @article{farnsworth_pollock_nichols_simons_hines_sauer_2002, title={A removal model for estimating detection probabilities from point-count surveys}, volume={119}, ISSN={["1938-4254"]}, DOI={10.1642/0004-8038(2002)119[0414:ARMFED]2.0.CO;2}, abstractNote={Abstract Use of point-count surveys is a popular method for collecting data on abundance and distribution of birds. However, analyses of such data often ignore potential differences in detection probability. We adapted a removal model to directly estimate detection probability during point-count surveys. The model assumes that singing frequency is a major factor influencing probability of detection when birds are surveyed using point counts. This may be appropriate for surveys in which most detections are by sound. The model requires counts to be divided into several time intervals. Point counts are often conducted for 10 min, where the number of birds recorded is divided into those first observed in the first 3 min, the subsequent 2 min, and the last 5 min. We developed a maximum-likelihood estimator for the detectability of birds recorded during counts divided into those intervals. This technique can easily be adapted to point counts divided into intervals of any length. We applied this method to unlimited-radius counts conducted in Great Smoky Mountains National Park. We used model selection criteria to identify whether detection probabilities varied among species, throughout the morning, throughout the season, and among different observers. We found differences in detection probability among species. Species that sing frequently such as Winter Wren (Troglodytes troglodytes) and Acadian Flycatcher (Empidonax virescens) had high detection probabilities (∼90%) and species that call infrequently such as Pileated Woodpecker (Dryocopus pileatus) had low detection probability (36%). We also found detection probabilities varied with the time of day for some species (e.g. thrushes) and between observers for other species. We used the same approach to estimate detection probability and density for a subset of the observations with limited-radius point counts.}, number={2}, journal={AUK}, author={Farnsworth, GL and Pollock, KH and Nichols, JD and Simons, TR and Hines, JE and Sauer, JR}, year={2002}, month={Apr}, pages={414–425} }
 @article{lichstein_simons_franzreb_2002, title={Landscape effects on breeding songbird abundance in managed forests.}, volume={12}, DOI={10.1890/1051-0761(2002)012[0836:leobsa]2.0.co;2}, abstractNote={We examined the relationship between songbird relative abundance and local and landscape-scale habitat variables in two predominately mid- to late-successional man- aged National Forests in the southern Appalachian Mountains, USA. We used partial- regression analysis to remove correlations between habitat variables measured at different spatial scales (local habitat and square landscape regions with sides of 0.5, 1, and 2 km) and between landscape composition (proportion of different land cover types) and pattern (spatial arrangement of land cover) variables. To account for spatial autocorrelation, we used autoregressive models that incorporated information on bird abundance in the spatial neighborhood surrounding each sample point. Most species, especially Neotropical mi- grants, were significantly correlated with at least one landscape variable. These correlations included both composition and pattern variables at 0.5-2 km scales. However, landscape effects explained only a small amount of the variation in bird abundance that could not be explained by local habitat. Our results are consistent with other studies of songbird abun- dance in large managed forests that have found weak or moderate landscape effects. These studies suggest that songbird abundance in forested landscapes will primarily reflect the quantity of different habitats in the landscape rather than the spatial arrangement of those habitats. Although some studies have suggested consolidating clearcuts in large managed forests to reduce edge and landscape heterogeneity, much of the current evidence does not support this management recommendation. An important future challenge in avian con- servation is to better understand how the importance of landscape effects varies in relation to (1) the amount of suitable habitat in the landscape, and (2) land use patterns at broader spatial scales.}, number={3}, journal={Ecological Applications}, author={Lichstein, J. W. and Simons, T. R. and Franzreb, K. E.}, year={2002}, pages={836–857} }
 @article{pollock_nichols_simons_farnsworth_bailey_sauer_2002, title={Large scale wildlife monitoring studies: statistical methods for design and analysis}, volume={13}, ISSN={["1099-095X"]}, DOI={10.1002/env.514}, abstractNote={Abstract}, number={2}, journal={ENVIRONMETRICS}, author={Pollock, KH and Nichols, JD and Simons, TR and Farnsworth, GL and Bailey, LL and Sauer, JR}, year={2002}, month={Mar}, pages={105–119} }
 @inbook{pearson_simons_2002, place={Washington, DC}, title={Spatial analysis of stopover habitats of Neotropical migratory birds}, ISBN={9781559637879}, booktitle={Predicting Species Occurrences: Issues of Scale and Accuracy}, publisher={Island Press}, author={Pearson, S.M. and Simons, T.R.}, editor={Scott, J.M.Editor}, year={2002} }
 @article{lichstein_simons_shriner_franzreb_2002, title={Spatial autocorrelation and autoregressive models in ecology}, volume={72}, ISSN={["1557-7015"]}, DOI={10.2307/3100099}, abstractNote={Recognition and analysis of spatial autocorrelation has defined a new paradigm in ecology. Attention to spatial pattern can lead to insights that would have been otherwise overlooked, while ignoring space may lead to false conclusions about ecological relationships. We used Gaussian spatial autoregressive models, fit with widely available software, to examine breeding habitat relationships for three common Neotropical migrant songbirds in the southern Appalachian Mountains of North Carolina and Tennessee, USA. In preliminary models that ignored space, the abundance of all three species was correlated with both local- and landscape-scale habitat variables. These models were then modified to account for broadscale spatial trend (via trend surface analysis) and fine-scale autocorrelation (via an autoregressive spatial covariance matrix). Residuals from ordinary least squares regression models were autocorrelated, indicating that the assumption of independent errors was violated. In contrast, residuals from autoregressive models showed little spatial pattern, suggesting that these models were appropriate. The magnitude of habitat effects tended to decrease, and the relative importance of different habitat variables shifted when we incorporated broadscale and then fine-scale space into the analysis. The degree to which habitat effects changed when space was added to the models was roughly correlated with the amount of spatial structure in the habitat variables. Spatial pattern in the residuals from ordinary least squares models may result from failure to include or adequately measure autocorrelated habitat variables. In addition, contagious processes, such as conspecific attraction, may generate spatial patterns in species abundance that cannot be explained by habitat models. For our study species, spatial patterns in the ordinary least squares residuals suggest that a scale of 500–1000 m would be appropriate for investigating possible contagious processes.}, number={3}, journal={ECOLOGICAL MONOGRAPHS}, author={Lichstein, JW and Simons, TR and Shriner, SA and Franzreb, KE}, year={2002}, month={Aug}, pages={445–463} }
 @article{farnsworth_simons_2001, title={How many baskets? Clutch sizes that maximize annual fecundity of multiple-brooded birds}, volume={118}, ISSN={["1938-4254"]}, DOI={10.1642/0004-8038(2001)118[0973:HMBCST]2.0.CO;2}, abstractNote={Abstract We developed deterministic models on the basis of nest survival rates and renesting behavior capable of predicting annual fecundity in birds. The models calculate probabilities of fledging from one to four nests within a discrete breeding season. We used those models to address theoretical issues related to clutch size. In general, birds require at least one day to lay an egg, and many species delay incubation until their entire clutch is laid. Because it takes longer to complete a larger clutch, and fewer such clutches can fit into a limited breeding season, there exists a clutch size for which annual fecundity is maximized. We asked, for a given amount of reproductive effort (i.e. a set number of eggs), does the age-old maxim “don't put all your eggs in one basket” apply? If so, in how many “baskets” should a nesting bird place its eggs? The answer depends on both likelihood of nest predation and length of the breeding season. Those results are consistent with the observed increase in clutch size with latitude (shorter breeding season length) and larger clutch sizes characteristic of cavity-nesting species (with higher nest survival rates). The models also predict that the size of replacement clutches should decrease as the breeding season progresses, and that intraseasonal decline in clutch size should be more pronounced when the breeding season is short.}, number={4}, journal={AUK}, author={Farnsworth, GL and Simons, TR}, year={2001}, month={Oct}, pages={973–982} }
 @article{hyde_simons_2001, title={Sampling plethodontid salamanders: Sources of variability}, volume={65}, ISSN={["1937-2817"]}, DOI={10.2307/3803013}, abstractNote={Recent evidence of possible worldwide amphibian population declines has highlighted the need for a better understanding of species-specific habitat associations and methodologies for monitoring long-term population trends. Great Smoky Mountains National Park is committed to incorporating salamander population monitoring into the park's long-term inventory and monitoring program because of the large number of unique species in the park, and evidence that salamanders are finely tuned indicators of environmental quality. We present data on spatial and temporal patterns in salamander diversity and abundance in Great Smoky Mountains National Park and compare the bias and effectiveness of 4 common sampling techniques. We found that large-scale habitat characteristics, including disturbance history, proximity of streams, and elevation are useful to explain patterns of salamander distribution and abundance. With the exception of soil moisture, microhabitat variables were not helpful in understanding variations in salamander relative abundance. Data collected over 2 years suggest that common salamander sampling techniques vary significantly in their effectiveness, and they may often violate assumptions required for comparing salamander population indices over space or time. Salamander counts on our sites were highly variable. Neither sampling variability nor detectability were constant across habitat types or species. These characteristics reduce power for detecting long-term population trends and suggest that some common sampling methods may not provide indices suitable for long-term population monitoring.}, number={4}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Hyde, EJ and Simons, TR}, year={2001}, month={Oct}, pages={624–632} }
 @article{davis_simons_groom_weaver_cordes_2001, title={The breeding status of the American Oystercatcher on the east coast of North America and breeding success in North Carolina}, volume={24}, ISSN={["1524-4695"]}, DOI={10.2307/1522030}, abstractNote={-We studied American Oystercatchers (Haematopus palliatus) by examining reproductive success and the factors affecting it at one location, and by examining the status and trends of breeding population numbers from Florida to Nova Scotia on the east coast of North America. We conducted our field research on Cape Lookout National Seashore, Carteret County, North Carolina from 1997 to 1999, and we documented larger scale breeding population trends by contacting state biologists and reviewing the literature and historical accounts. Presence of eggs and young were checked two to five times per week (by observing from a distance), and efforts were made to determine the reasons for loss of the nest contents. We monitored a total of 245 nests and found low productivity. At least one egg in 32 (13%) nests hatched and one or more chicks fledged from 12 broods. Overall, 14 chicks successfully fledged (nine from North Core Banks and five from South Core Banks) during the three years of the study. Of the 213 clutches that did not hatch, 163 (76%) failed because of predation, and 46 (22%) because of overwash or severe weather. Our minimum estimate for the number of oystercatchers breeding along the entire Atlantic coast and the Gulf coast of Florida is 1,624 pairs. North of Virginia, numbers appear to be stable or slowly increasing and the species has expanded as far north as Cape Sable Island in Nova Scotia. From Virginia south, breeding numbers show a decline in recent years. The number of oystercatchers breeding on barrier islands in Virginia has decreased by more than 50% in the last 20 years. Given their relatively small numbers and inherently low productivity, American Oystercatchers are at risk in rapidly changing coastal ecosystems. Received 1 June 2000, accepted 11 October 2000.}, number={2}, journal={WATERBIRDS}, author={Davis, MB and Simons, TR and Groom, MJ and Weaver, JL and Cordes, JR}, year={2001}, month={Aug}, pages={195–202} }
 @article{simons_pearson_moore_2000, title={Application of spatial models to the stopover ecology of trans-Gulf migrants.}, volume={20}, journal={Stopover ecology of Nearctic-Neotropical landbird migrants: Habitat relations and conservation implications}, publisher={Camarillo, CA: Cooper Ornithological Society}, author={Simons, T. R. and Pearson, S. M. and Moore, F. R.}, year={2000}, pages={4–14} }
 @book{simons_shriner_2000, title={Ecology and conservation of Neotropical migrants in the southern Appalachians}, journal={1999 Annual report to the National Park Service}, author={Simons, T.R. and Shriner, S.A.}, year={2000} }
 @article{simons_farnsworth_shriner_2000, title={Evaluating Great Smoky Mountains National Park as a population source for the Wood Thrush}, volume={14}, ISSN={["0888-8892"]}, DOI={10.1046/j.1523-1739.2000.98606.x}, abstractNote={Abstract: The prevailing fragmentation paradigm predicts that large, intact forests are acting as population sources for Neotropical migrant landbirds. We used the Wood Thrush (  Hylocichla mustelina) as a model for evaluating the role Great Smoky Mountains National Park (the largest national park in the eastern United States) may play in maintaining regional songbird populations. We estimated the annual productivity of Wood Thrushes in the park by combining observations on the birds' distribution, abundance, and productivity with estimates of habitat availability. We estimated a breeding population of approximately 10,000 nesting pairs using habitat models developed from over 2500 point‐count censuses conducted across the park. Data from 426 nests monitored from 1992 to 1997 produced a daily nest survival rate of 0.96. We estimated an annual fecundity of 2.76 fledglings per breeding pair, based on a model that incorporated the re‐nesting behavior of Wood Thrushes. Results indicate that the park is producing approximately 3000 surplus female young each year. Daily nest survival rates were below those reported in other studies of Wood Thrushes in large forest tracts. The relatively high productivity of 3.31 nestlings per successful nest suggests that, in the absence of predation, the park provides high‐quality nesting habitat for Wood Thrushes, but that it may also support a more diverse and abundant predator community than more disturbed or less contiguous sites. The difficulties of estimating the size of continental breeding bird populations make assessing the significance of the park within a regional landscape context problematic, but our estimates suggest that, although the park is functioning as a substantial population source on a local scale, its potential to sustain regional or continental Wood Thrush populations is limited. Our findings suggest that species such as the Wood Thrush are capable of moderate levels of surplus productivity in high‐quality habitat, but that extensive areas of suitable habitat outside protected areas and other public lands will be required to sustain continental breeding populations.}, number={4}, journal={CONSERVATION BIOLOGY}, author={Simons, TR and Farnsworth, GL and Shriner, SA}, year={2000}, month={Aug}, pages={1133–1144} }
 @book{simons_bailey_hyde_pollock_2000, title={Evaluation of salamander habitat associations and population monitoring techniques in Great Smoky Mountains National Park}, journal={1999 Annual report to the Environmental Protection Agency}, author={Simons, T.R. and Bailey, L.L. and Hyde, E.J. and Pollock, K.J.}, year={2000} }
 @article{farnsworth_simons_2000, title={Observations of Wood Thrush nest predators in a large contiguous forest}, volume={112}, ISSN={["0043-5643"]}, DOI={10.1676/0043-5643(2000)112[0082:oowtnp]2.0.co;2}, abstractNote={Abstract We used inexpensive (<$30) cameras to document predators at active Wood Thrush (Hylocichla mustelina) nests in Great Smoky Mountains National Park. We observed such predators as black rat snakes (Elaphe obsoleta), American Crows (Corvus brachyrhynchos), southern flying squirrels (Glaucomys volans), and black bears (Ursus americanus) remove the contents of nests. Camera installation had no measurable effect on nest survival; daily nest survival was approximately 0.96 for nests with and without cameras. However, placement of an artificial egg trigger in the nest appeared to reduce hatching success. The immobile egg trigger might have interfered with the female Wood Thrush's ability to incubate her eggs. The variety of nest predators observed and the moderate daily survival rates recorded suggest that predation is an important constraint on Wood Thrushes nesting in large contiguous forests.}, number={1}, journal={WILSON BULLETIN}, author={Farnsworth, GL and Simons, TR}, year={2000}, month={Mar}, pages={82–87} }
 @book{simons_lichstein_franzreb_2000, title={The effects of landscape pattern, core areas, and forest management practices on avian communities in the southern Appalachians}, journal={1999 Annual report to the U.S. Forest Service}, author={Simons, T.R. and Lichstein, J.L. and Franzreb, K.E.}, year={2000} }
 @article{farnsworth_weeks_simons_2000, title={Validating the assumptions of the Mayfield method}, volume={71}, ISSN={["0273-8570"]}, DOI={10.1648/0273-8570-71.4.658}, abstractNote={Abstract We tested the assumptions of the Mayfield method (Mayfield 1975) using 416 Wood Thrush (Hylocichla mustelina) nests monitored from 1993–1997 in the Great Smoky Mountains National Park. We tested for differences in nest survival throughout the breeding season and throughout the nesting cycle. We compared the Mayfield cumulative survival curve with a modified version of the Kaplan-Meier with staggered entry. In addition, we compared the group of nests found during nest initiation with those found later in the nesting cycle. There was no evidence nest survival varied through the breeding season or with different stages of the nesting cycle. Furthermore, the Kaplan-Meier survival curve agreed with the Mayfield calculation. We found no evidence of heterogeneity. Validation of Mayfield assumptions is important because the method is widely used, allows for statistical comparisons, and is critical for estimating seasonal fecundity in bird populations.}, number={4}, journal={JOURNAL OF FIELD ORNITHOLOGY}, author={Farnsworth, GL and Weeks, KC and Simons, TR}, year={2000}, pages={658–664} }
 @book{simons_johnson_1999, title={Assessing the diversity and habitat associations of salamanders in Great Smoky Mountains National Park}, journal={1998 Annual report to the National Park Service}, author={Simons, T.R. and Johnson, E.}, year={1999} }
 @book{simons_shriner_1999, title={Ecology and conservation of Neotropical migrants in the southern Appalachians}, journal={1998 Annual report to the National Park Service}, author={Simons, T.R. and Shriner, S.A.}, year={1999} }
 @article{farnsworth_simons_1999, title={Factors affecting nesting success of wood thrushes in Great Smoky Mountains National Park}, volume={116}, ISSN={["0004-8038"]}, DOI={10.2307/4089686}, abstractNote={Recent evidence suggests that the nesting success of forest-interior Neotropical migrants is lower in fragmented habitat. We examined the nesting success of Wood Thrushes (Hylocichla mustelina) in a large contiguous forest from 1993 to 1997. From a sample of 416 nests we tested for predictors of daily nest survival rates, including activity at the nest and vegetation parameters at the nest site. We tested whether disturbance during nest checks (as measured by the behavior of the adults) was related to subsequent nest predation. Females were more likely to vocalize when brooding chicks than when incubating eggs. However, we found no evidence that observer disturbance or Wood Thrush activity influenced daily nest survival rates. Wood Thrushes nested predominately in small hemlocks, generally surrounded by many other small hemlocks. However, survival rates of nests in hemlocks were not significantly different from those in other substrates. Overall, neither activity at the nest nor habitat in the vicinity of the nest was a good predictor of nesting success, and only one vegetation characteristic, a measure of concealment, was significantly correlated with successful nesting. Brood parasitism by Brown-headed Cowbirds (Molothrus ater) was extremely low (<2% of nests parasitized). However, nesting success was moderate (daily survival rate = 0.958) when compared with other published studies from more-fragmented landscapes. Our results suggest that daily nest survival rates do not increase monotonically from small to very large forest patches.}, number={4}, journal={AUK}, author={Farnsworth, GL and Simons, TR}, year={1999}, month={Oct}, pages={1075–1082} }
 @article{farnsworth_simons_1999, place={Hancock, Michigan}, title={Is Great Smoky Mountains National Park acting as a population source for Wood Thrushes?}, volume={10}, journal={Research and Resources Management in Parks and Public Lands}, publisher={The George Wright Society}, author={Farnsworth, G.L. and Simons, T.R.}, year={1999}, pages={109–113} }
 @book{simons_lichstein_franzreb_1999, title={The effects of landscape pattern, core areas, and forest management practices on avian communities in the southern Appalachians}, journal={1998 Annual report to the U.S. Forest Service}, author={Simons, T.R. and Lichstein, J.L. and Franzreb, K.E.}, year={1999} }
 @inbook{simons_hodges_1998, title={Dark-rumped petrel}, number={345}, booktitle={The Birds of North America: Life histories for the 21st century}, publisher={Washington, D.C.: American Ornithologists' Union ; Philadelphia, PA.: Academy of Natural Sciences}, author={Simons, T. R. and Hodges, C. N.}, editor={A. Poole, P. Stettenheim and Gill, F.Editors}, year={1998}, pages={1–24} }
 @book{simons_shriner_1998, title={Ecology and conservation of Neotropical migrants in the southern Appalachians}, journal={1997 Annual report to the National Park Service}, author={Simons, T.R. and Shriner, S.A.}, year={1998} }
 @book{simons_farnsworth_1998, title={Evaluating Great Smoky Mountains National Park as a population source for Wood Thrush}, journal={1997 Annual report to the National Park Service}, author={Simons, T.R. and Farnsworth, G.L.}, year={1998} }
 @book{ross_rabenold_simons_1998, title={Indicator Birds of the Costa Rican Cloud Forest}, ISBN={0- 938027-42-5}, publisher={Library of Natural Sounds, Cornell Laboratory of Ornithology}, author={Ross, D.L., Jr. and Rabenold, K.N. and Simons, T.R.}, year={1998} }
 @inbook{simons_sherrod_collopy_jenkins_1998, place={Research Triangle Park, NC}, title={Restoring the Bald Eagle}, booktitle={Exploring Ecology and Its Applications}, publisher={Sigma Xi}, author={Simons, T.R. and Sherrod, S.K. and Collopy, M.W. and Jenkins, M.A.}, editor={Kareiva, P.M.Editor}, year={1998} }
 @book{simons_lichstein_franzreb_1998, title={The effects of landscape pattern, core areas, and forest management practices on avian communities in the southern Appalachians}, journal={1997 Annual report to the U.S. Forest Service}, author={Simons, T.R. and Lichstein, J.L. and Franzreb, K.E.}, year={1998} }
 @inbook{simons_rabenold_buehler_collazo_franzreb_1998, title={The role of indicator species: Neotropical migratory song birds}, booktitle={Ecosystem management for sustainability: principles and practices illustrated by the Southern Appalachian Man and Biosphere Cooperative}, publisher={CRC Press}, author={Simons, T.R. and Rabenold, K.N. and Buehler, D.A. and Collazo, J. and Franzreb, K.E.}, editor={Peine, J.Editor}, year={1998} }
 @book{simons_shriner_1997, title={Ecology and conservation of Neotropical migrants in the southern Appalachians}, journal={1996 Annual report to the National Park Service}, author={Simons, T.R. and Shriner, S.A.}, year={1997} }
 @book{simons_farnsworth_1997, title={Evaluating Great Smoky Mountains National Park as a population source for Wood Thrush}, journal={1996 Annual report to the National Park Service}, author={Simons, T.R. and Farnsworth, G.L.}, year={1997} }
 @article{rakocinski_heard_le croy_mclelland_simons_1996, title={Responses by macrobenthic assemblages to extensive beach restoration at Perdido Key, Florida, U.S.A}, volume={12}, journal={Journal of Coastal Research}, author={Rakocinski, C.F. and Heard, R.W. and Le Croy, S.E.Le and McLelland, J.A. and Simons, T.R.}, year={1996}, pages={326–353} }
 @book{simons_rabenold_farnsworth_1995, title={Characterization of deciduous forest breeding bird communities of Great Smoky Mountains National Park}, author={Simons, T.R. and Rabenold, K. and Farnsworth, G.L.}, year={1995} }
 @book{simons_1995, title={Coastal Park Inventory and Monitoring Handbook}, number={NPS/SERNCSU/NRTR-95/01}, author={Simons, T.R.}, year={1995} }
 @book{simons_farnsworth_1995, title={Evaluating Great Smoky Mountains National Park as a population source of Wood Thrush}, journal={Annual report to the National Park Service}, author={Simons, T.R. and Farnsworth, G.L.}, year={1995} }
 @inbook{moore_kerlinger_gauthreaux_simons_1995, title={Habitat Requirements During Migration: Important Link in Conservation}, booktitle={Ecology and Management of Neotropical Migratory Birds: A Synthesis and Review of Critical Issues}, publisher={Oxford University Press}, author={Moore, F.R. and Kerlinger, P. and Gauthreaux, S.A., Jr. and Simons, T.R.}, editor={Martin, T.E. and Finch, D.M.Editors}, year={1995} }
 @inbook{simons_nol_boettcher_1994, place={Ithaca, NY}, title={American Oystercatcher (Haematopus palliatus)}, ISSN={1061-5466}, url={http://dx.doi.org/10.2173/bna.082}, DOI={10.2173/bna.82}, booktitle={The Birds of North America Online}, publisher={Cornell Laboratory of Ornithology}, author={Simons, T.R. and Nol, E. and Boettcher, R,}, editor={Poole, Alan and Gill, FrankEditors}, year={1994} }
 @article{grundel_simons_1994, title={Neotropical migratory bird workshop and research}, volume={14}, number={3}, journal={Park Science}, author={Grundel, R. and Simons, T.R.}, year={1994}, pages={1–5} }
 @book{simons_moore_1993, title={Operation of EMPRESS II and the behavior of migratory birds in the Gulf of Mexico}, institution={Naval Sea Systems Command}, author={Simons, T.R. and Moore, F.R.}, year={1993} }
 @book{esher_simons_1993, title={Red Wolf propagation on Horn Island, Mississippi: Red Wolf ecological studies.}, author={Esher, R.J. and Simons, T.R.}, year={1993} }
 @article{rakocinski_heard_lecroy_mclelland_simons_1993, title={Seaward Change and Zonation of the Sandy-Shore Macrofauna at Perdido Key, Florida, U.S.A.}, volume={36}, ISSN={0272-7714}, url={http://dx.doi.org/10.1006/ecss.1993.1007}, DOI={10.1006/ecss.1993.1007}, abstractNote={Abstract To elucidate spatial community patterns, we sampled macrofauna from 36 stations located along four 800 m seaward transects at Perdido Key, Florida. Several faunal indices, including species richness, total density, diversity, and species composition, changed markedly with increasing distance from shore. Species richness was greater at the outer stations by a factor of 20, ranging from five species per 0·125 m 2 in the swash zone, to as many as 100 species per 0·125 m 2 at 800 m offshore. Total density also increased seaward from shore by an order of magnitude, from 2000 per m 2 to 20 000 per m 2 . Seaward spatial distributions of dominant species along the four transects exemplified coenoclines with distinct breaks, noticeable as steep reductions in densities of contiguous dominant species. Coenocline breaks coincided with peak diversity and evenness levels as well as with relatively low total densities at distances between 100 and 200 m from shore, midway along the seaward slopes of transect depth profiles. These faunal discontinuities presumably coincided with intermediate levels of disturbance from wave action. Nearshore spatial changes in faunal indices among transects corresponded with changes in habitat, as characterized by depth and sediment. The existence of four major faunal zones within the 800 m seaward distance was suggested by a Detrended Correspondence Analysis of 45 common species and 36 stations. Taken together, these findings indicated that a primary environmental gradient consisting of seaward variation in depth, sediment characteristics, and turbulence largely determines sandy-shore community structure.}, number={1}, journal={Estuarine, Coastal and Shelf Science}, publisher={Elsevier BV}, author={Rakocinski, C.F. and Heard, R.W. and LeCroy, S.E. and McLelland, J.A. and Simons, T.}, year={1993}, month={Jan}, pages={81–104} }
 @inbook{bartle_hu_pyle_simons_stahl_woodby_1993, place={Ottawa}, title={Status and ecology of gadfly petrels in the temperate North Pacific}, booktitle={The status ecology and conservation of marine birds of the North Pacific}, publisher={Canadian Wildlife Service}, author={Bartle, J.A. and Hu, D. and Pyle, P. and Simons, T.R. and Stahl, J.C. and Woodby, D.}, editor={Vermeer, K. and Briggs, K.T. and Morgan, K.H. and Siegel Causey, D.Editors}, year={1993} }
 @inbook{moore_gauthreaux_kerlinger_simons_1993, place={Fort Collins, Colorado}, title={Stopover habitat: Management implications and guidelines}, booktitle={Status and management of Neotropical migratory birds}, publisher={U.S. Forest Service}, author={Moore, F.R. and Gauthreaux, S.A. and Kerlinger, P. and Simons, T.R.}, editor={Finch, D.M. and Stangel, P.J.Editors}, year={1993} }
 @inbook{moore_simons_1992, place={Washington, D.C}, title={Habitat suitability and the stopover ecology of Neotropical passerine migrants}, booktitle={Ecology and Conservation of Neotropical Migrant Landbirds}, publisher={Smithsonian Institution Press}, author={Moore, F.R. and Simons, T.R.}, editor={Hagan, J.W. and Johnston, D.W.Editors}, year={1992} }
 @book{rabenold_simons_1991, title={Genetic diversity in barrier island Carolina Wren populations}, author={Rabenold, P.P. and Simons, T.R.}, year={1991} }
 @article{rakocinski_heard_simons_their_1991, title={Macroinvertebrate associations from beaches of selected barrier islands in the Northern Gulf of Mexico: important environmental relationships}, volume={48}, journal={Bulletin of Marine Science}, author={Rakocinski, C. and Heard, R. and Simons, T.R. and Their, D.}, year={1991}, pages={689–701} }
 @article{kuenzi_moore_simons_1991, title={Stopover of Neotropical Landbird Migrants on East Ship Island Following Trans-Gulf Migration}, volume={93}, ISSN={0010-5422}, url={http://dx.doi.org/10.2307/3247722}, DOI={10.2307/3247722}, abstractNote={The ecophysiology of Neotropical landbird migrants was studied in relation to energetic condition following trans-Gulf migration in 1987, 1988, and 1989. Most birds captured on East Ship Island, a barrier island off the Mississippi coast, had exhausted fat reserves crossing the Gulf of Mexico and were near fat-free mass. Few birds were recaptured after the day of their first capture, suggesting that migrants departed the day of their arrival or that night. Lean migrants occurred more frequently in samples of recaptured migrants, although length of stay was not a clear function of arrival mass nor did change in mass simply increase with stopover length. Most species were characterized by loss of body mass or by rates of change that essentially maintained arrival mass during stopover. Rates of change in mass were positively correlated with energy demand for several species. Fatdepleted birds appeared to compensate for their condition, presumably by increasing their rate of energy acquisition. Estimates of prey abundance did not differ between years, which might explain why stopover length and rate of gain did not vary between years. We conclude that many migrants left ES1 because they found few opportunities to satisfy energy demand, while others stayed because of constraints unrelated to their energy balance or because the benefits of rejecting the habitat were outweighed by the cost of finding a more suitable site. Kev words: Mr energetic condition; ,fat deposition. -}, number={4}, journal={The Condor}, publisher={Oxford University Press (OUP)}, author={Kuenzi, Amy Jo and Moore, Frank R. and Simons, Ted R.}, year={1991}, month={Nov}, pages={869} }
 @article{kepler_kepler_simons_hobdy_simons_1990, place={Honolulu, HI}, title={Hawaii's Seabird Islands, No. 3: Moku-Ho'Oniki and Kanaha Rock, Molokai}, volume={50}, number={9}, journal={'Elepaio}, publisher={Hawai'i Audobon Society}, author={Kepler, C.B. and Kepler, A.K. and Simons, T.R. and Hobdy, B. and Simons, P.M.}, year={1990}, pages={75–81} }
 @article{moore_kerlinger_simons_1990, title={Stopover on a Gulf Coast Barrier Island by spring trans-Gulf migrants}, volume={103}, journal={Wilson Bulletin}, author={Moore, F.R. and Kerlinger, P. and Simons, T.R.}, year={1990}, pages={487–500} }
 @inproceedings{simons_1990, place={Fort Collins, Colorado}, title={The migratory bird watch program: an overview and summary of research at Gulf Islands National Seashore}, booktitle={Proceedings of the nongame migratory bird workshop, Atlanta, GA}, publisher={U.S. Fish and Wildlife Service}, author={Simons, T.R.}, year={1990} }
 @article{simons_whittow_1989, title={A seabird in the house of the sun}, journal={Natural History}, author={Simons, T.R. and Whittow, C.W.}, year={1989}, month={Mar}, pages={50–53} }
 @article{simons_1989, title={Proposed Migratory Bird Watch to encompass research, monitoring, and interpretation}, volume={9}, number={3}, journal={Park Science}, author={Simons, T.R.}, year={1989}, pages={8} }
 @article{holier_mason_dawson_simons_wooten_1989, title={Reestablishment of the Perdido Key Beach Mouse (Peromyscus polionotus trissyllepsis) on Gulf Islands National Seashore}, volume={3}, ISSN={0888-8892}, url={http://dx.doi.org/10.1111/j.1523-1739.1989.tb00245.x}, DOI={10.1111/j.1523-1739.1989.tb00245.x}, abstractNote={Abstract:  In April 1986, the endangered Perdido Key beach mouse (Peromyscus polionotus trissyllepsis) existed only as a small population of less than 30 animals on the western end of Perdido Key at Gulf State Park, Alabama This population was vulnerable to extinction from a variety of causes. Fifteen pairs of mice from Alabama were moved approximately 20 km on the same island to Gulf Islands National Seashore Florida between November 1986 and April 1988. The Alabama population was surveyed by live‐trapping before each removal and showed a large increase during this study. Eleven pairs of mice were released into enclosures to stimulate burrowing and reduce dispersal at the release site. The last four pairs w e released unrestricted into the dune habitat Trapping in July 1988 revealed that virtually all available dune habitat (11,000 linear m; approximately 160 ha) had been occupied by the mice. Fifty‐five individuals were captured including four of the released mice. Exchanges between the populations are recommended to prevent loss of genetic diversity. Future research should investigate demographics, dispersal pattern, and the application of DNA fingerprinting techniques to determine rates of gene flow in the population. The Perdido Key beach mouse provides an excellent model for studying the effects of a population bottleneck on genetic diversity and testing the predictions of population viability analysis.}, number={4}, journal={Conservation Biology}, publisher={Wiley}, author={Holier, N. R. and Mason, D. W. and Dawson, R. M. and Simons, T. and Wooten, M.C.}, year={1989}, month={Dec}, pages={397–404} }
 @inproceedings{simons_scurry_1988, title={Application of GIS technology to monitor barrier island change: Integration of SAGIS and MOSS and Gulf Islands National Seashore}, booktitle={Proceedings fifth national MOSS users workshop. Louisiana Sea Grant College Program, Baton Rouge, and U.S. Fish and Wildlife Service, Slidell, LA}, author={Simons, T.R. and Scurry, J.D.}, year={1988} }
 @article{simons_sherrod_collopy_jenkins_1988, title={Restoring the Bald Eagle}, volume={76}, journal={American Scientist}, author={Simons, T.R. and Sherrod, S.K. and Collopy, M.W. and Jenkins, M.A.}, year={1988}, pages={252–260} }
 @inbook{simons_1987, title={The role of research in developing resource management tools at Gulf Islands National Seashore}, booktitle={Estuarine and Coastal Management - Tools of the Trade}, publisher={The Coastal Society}, author={Simons, T.R.}, year={1987} }
 @article{pierce_simons_1986, title={The influence of human disturbance on Tufted Puffin breeding success}, volume={103}, journal={The Auk}, author={Pierce, J.D. and Simons, T.R.}, year={1986}, pages={214–216} }
 @article{simons_1985, title={Biology and Behavior of the Endangered Hawaiian Dark-Rumped Petrel}, volume={87}, ISSN={0010-5422}, url={http://dx.doi.org/10.2307/1366887}, DOI={10.2307/1366887}, number={2}, journal={The Condor}, publisher={Oxford University Press (OUP)}, author={Simons, Theodore R.}, year={1985}, month={May}, pages={229} }
 @article{simons_simons_kepler_kepler_1985, title={Hawaii's seabird islands, No.2: Hulu Island and vicinity}, volume={45}, journal={'Elepaio}, author={Simons, T.R. and Simons, P.M. and Kepler, C.B. and Kepler, A.K.}, year={1985}, pages={111–113} }
 @article{simons_1984, title={A Population Model of the Endangered Hawaiian Dark-Rumped Petrel}, volume={48}, ISSN={0022-541X}, url={http://dx.doi.org/10.2307/3801768}, DOI={10.2307/3801768}, number={4}, journal={The Journal of Wildlife Management}, publisher={JSTOR}, author={Simons, Theodore R.}, year={1984}, month={Oct}, pages={1065} }
 @inbook{simons_whittow_1984, place={Plenum, New York}, title={Energetics of growth in the Dark-rumped Petrel}, booktitle={Seabird Energetics}, author={Simons, T.R. and Whittow, G.C.}, editor={Whittow, G.C.Editor}, year={1984} }
 @article{kepler_kepler_simons_1984, title={Hawaii's seabird islands, No. 1: Moke'ehia}, volume={44}, journal={'Elepaio}, author={Kepler, C.B. and Kepler, A.K. and Simons, T.R.}, year={1984}, pages={71–74} }
 @article{whittow_simons_pettit_1984, title={Water loss from the eggs of a tropical sea bird (Pterodroma phaeopygia) at high altitude}, volume={78}, ISSN={0300-9629}, url={http://dx.doi.org/10.1016/0300-9629(84)90592-9}, DOI={10.1016/0300-9629(84)90592-9}, abstractNote={1. The water loss from the eggs of the dark-rumped petrel nesting at an altitude of 3000m in the Hawaiian Islands was studied. 2. The conditions at the nest site were extremely dry and the calculated nest ventilation was very low (17.21/day). 3. Comparisons with data from other Procellariiformes nesting at sea level suggested that the daily rate of water loss from the eggs of the dark-rumped petrel was high (134.5% of the predicted value for a procellariiform egg at sea level). 4. The egg shells were thin and the shell mass was low—83.9% and 73.5%, respectively, of the values predicted for a procellariiform egg at sea level. 5. It is believed that these features of the eggs are related to the altitude of the nesting site.}, number={3}, journal={Comparative Biochemistry and Physiology Part A: Physiology}, publisher={Elsevier BV}, author={Whittow, G.C and Simons, T.R and Pettit, T.N}, year={1984}, month={Jan}, pages={537–540} }
 @book{simons_1983, place={Seattle, Washington}, title={Biology and conservation of the endangered Hawaiian Dark-rumped Petrel (Pterodroma phaeopygia sandwichensis)}, number={CPSU/UW 83-2}, institution={National Park Service, Cooperative Park Studies Unit, College of Forest Resources, University of Washington}, author={Simons, T.R.}, year={1983} }
 @article{simons_1981, title={A Simple Event Recorder for Monitoring Cavity-Dwelling Animals}, volume={62}, ISSN={0027-3716}, url={http://dx.doi.org/10.2307/3534452}, DOI={10.2307/3534452}, number={1}, journal={The Murrelet}, publisher={JSTOR}, author={Simons, Theodore R.}, year={1981}, pages={27} }
 @article{simons_1981, title={Behavior and attendance patterns of the Fork-tailed Storm Petrel}, volume={98}, journal={The Auk}, author={Simons, T.R.}, year={1981}, pages={145–158} }
 @inproceedings{simons_simons_1981, place={Honolulu, Hawaii}, title={Breeding biology of the Dark-rumped Petrel in the Hawaiian Islands}, booktitle={Proceedings of the Third Conference in Natural Sciences, Hawaii Volcanoes National Park}, publisher={CPSU/UH, University of Hawaii}, author={Simons, T.R. and Simons, P.M.}, year={1981} }
 @inproceedings{simons_1981, title={Seabirds and park management}, booktitle={Proceedings; Hawaii Forestry and Wildlife Conference 1980. U.S. Dept. Agriculture}, publisher={U.S. Forest Service}, author={Simons, T.R.}, year={1981} }
 @article{simons_1980, title={Discovery of a Ground-Nesting Marbled Murrelet}, volume={82}, ISSN={0010-5422 1938-5129}, url={http://dx.doi.org/10.2307/1366777}, DOI={10.2307/1366777}, abstractNote={An exposed ground nest of a Marbled Murrelet discovered on 8 July 1978, on East Amatuli Island, Barren Islands, Alaska, was studied for 51 days. The behavior and activity patterns of the adults throughout incubation and the nestling stage exhibit adaptations to reduce detection of the nest and avoid predators. The highly cryptic chick remains alone on the nest for approximately 27 days and is fed at least once a night by the adults. A tenacious layer of down is apparently preened off by the chick just prior to fledging, allowing the nestling to remain inconspicuous until juvenal plumage has fully developed. Analysis of the chick's growth parameters indicates a relatively high rate of growth as compared with other alcids. This is apparently made possible because the food supply is readily accessible, and in turn reduces the period of the chick's exposure to predators. Fledging behavior in the Marbled Murrelet remains a mystery although evidence indicates that chicks fly to sea and are independent after leaving the nest.}, number={1}, journal={The Condor}, publisher={Oxford University Press (OUP)}, author={Simons, Theodore R.}, year={1980}, month={Feb}, pages={1–9} }