@article{michel_strickland_demarais_belant_kautz_duquette_beyer_chamberlain_miller_shuman_et al._2020, title={Relative reproductive phenology and synchrony affect neonate survival in a nonprecocial ungulate}, volume={34}, ISSN={0269-8463 1365-2435}, url={http://dx.doi.org/10.1111/1365-2435.13680}, DOI={10.1111/1365-2435.13680}, abstractNote={Abstract


Degree of reproductive synchronization in prey is hypothesized as a predator defense strategy reducing prey risk via predator satiation or predator avoidance. Species with precocial young, especially those exposed to specialist predators, should be highly synchronous to satiate predators (predator satiation hypothesis), while prey with nonprecocial (i.e. altricial) young, especially those exposed to generalist predators, should become relatively asynchronous to avoid predator detection (predator avoidance hypothesis). The white‐tailed deer Odocoileus virginianus in North America is an example of a nonprecocial ungulate that uses the hider strategy early in life; its primary predator (coyote; Canis latrans) is a generalist, making white‐tailed deer a good model species to test the predator avoidance hypothesis.

We used birth dates and known fates of white‐tailed deer neonates (n = 1,032) across nine study sites varying in relative synchrony and predator assemblages to test the predator avoidance hypothesis. We predicted that relative birthing asynchrony of the population would increase relative survival at the population level; therefore, at the individual scale, neonate birth date nearer to mean birthing date in a respective population would not influence individual survival.

Coyotes were responsible for the majority of predation events, and survival of those neonates increased the closer the individual was born to peak birthing season in each respective population. Also, at the population level, reproductive asynchronization negatively affected survival.

Contrary to the predator avoidance hypothesis, our data indicate patterns in neonate survival for white‐tailed deer better support the predator satiation hypothesis at the individual and population level. Additionally, coyotes may present a selective force great enough to shift reproductive synchrony such that predator satiation may become a feasible defense strategy for neonates at local spatial scales.

Our results indicate that synchronizing reproduction may still be the most effective strategy to reduce individual predation risk from generalist predators, particularly when the window of heightened resource availability to the prey is narrow.

A free Plain Language Summary can be found within the Supporting Information of this article.}, number={12}, journal={Functional Ecology}, publisher={Wiley}, author={Michel, Eric S. and Strickland, Bronson K. and Demarais, Stephen and Belant, Jerrold L. and Kautz, Todd M. and Duquette, Jared F. and Beyer, Dean E., Jr and Chamberlain, Michael J. and Miller, Karl V. and Shuman, Rebecca M. and et al.}, editor={Crocker, DanielEditor}, year={2020}, month={Sep}, pages={2536–2547} }
 @article{garabedian_moorman_peterson_kilgo_2020, title={Effects of group size and group density on trade‐offs in resource selection by a group‐territorial central‐place foraging woodpecker}, volume={162}, ISSN={0019-1019 1474-919X}, url={http://dx.doi.org/10.1111/ibi.12733}, DOI={10.1111/ibi.12733}, abstractNote={Trade‐offs in resource selection by central‐place foragers are driven by the need to balance the benefits of selecting resources against the costs of travel from the central place. For group‐territorial central‐place foraging birds, trade‐offs in resource selection are likely to be complicated by a competitive advantage for larger groups at high group density that may limit accessibility of high‐quality distant resources to small groups. We used the group‐territorial, central‐place foraging Red‐cockaded Woodpecker Leuconotopicus borealis (RCW) as a case study to test predictions that increases in group density lead to differences in foraging distances and resource selection for groups of different sizes. We used GPS tracking and LiDAR‐derived habitat data to model effects of group size on foraging distances and selection for high‐quality pines (≥ 35.6 cm diameter at breast height (dbh)) and lower quality pines (25.4–35.6 cm dbh) by RCW groups across low (n = 14), moderate (n = 10) and high group density (n = 10) conditions. At low and moderate group density, all RCW groups selected distant high‐quality pines in addition to those near the central place because competition for resources was low. In contrast, at high group density, larger groups travelled further to select high‐quality pines, whereas smaller groups selected high‐quality pines only when they were close to the central place and, conversely, were more likely to select lower quality pines at greater distances from the central place. Selection for high‐quality pines only when close to the cavity tree cluster at high group density is important to long‐term fitness of small RCW groups because it allows them to maximize benefits from both territorial defence and selecting high‐quality resources while minimizing costs of competition. These relationships suggest that intraspecific competition at high group density entails substantive costs to smaller groups of territorial central‐place foragers by limiting accessibility of distant high‐quality foraging resources.}, number={2}, journal={Ibis}, publisher={Wiley}, author={Garabedian, James E. and Moorman, Christopher E. and Peterson, M. Nils and Kilgo, John C.}, year={2020}, month={Apr}, pages={477–491} }
 @article{garabedian_moorman_peterson_kilgo_2019, title={Neighboring group density is more important than forest stand age to a threatened social woodpecker population}, volume={2019}, ISSN={0909-6396}, url={http://dx.doi.org/10.2981/wlb.00574}, DOI={10.2981/wlb.00574}, abstractNote={Effective conservation of group-living forest wildlife requires information on how forest age moderates population parameters. Relationships between forest age and demographics can guide long-term management for wildlife populations that are expanding in relatively young second-growth forests in response to ongoing habitat management. We examined how forest age moderates effects of group density on long-term trends in group size and fledgling production in the endangered red-cockaded woodpecker Dryobates borealis (RCW) on the Savannah River Site, SC (SRS). We used 32 years of RCW monitoring data and generalized additive models to: 1) model long-term changes in average RCW group size and fledgling production; and 2) model effects of neighboring group density and neighboring group sizes across a gradient of forest age within 800 m of a group's cavity tree cluster. Average fledgling production oscillated over 2–3 year periods, but longer term evaluation indicated oscillations dampened and average fledgling production slightly decreased over time. Average group size fluctuated abruptly over 2–3 year periods from 1985 to 1994, but longer term evaluation indicated a general increase in group sizes from 1985 to 1994, followed by declines from 1995 to 2007, and a steady increase after 2010. Average fledgling production increased in response to neighboring group density but decreased as neighboring group sizes increased. In contrast, average group sizes increased in response to greater neighboring group density and neighboring group sizes. Stand age did not affect these relationships. Collectively, these results suggest forest age does not directly moderate effects of neighboring group density or group sizes on long-term average group size and fledgling production in the SRS RCW population. Although forest structure has been linked to increased RCW group sizes and productivity, our results suggest that with ongoing habitat management, long-term changes in group size and fledgling production will be driven primarily by group density conditions rather than changing forest age.}, number={1}, journal={Wildlife Biology}, publisher={Wiley}, author={Garabedian, James E. and Moorman, Christopher E. and Peterson, M. Nils and Kilgo, John C.}, year={2019}, month={Dec} }
 @article{garabedian_peterson_moorman_kilgo_2019, title={Using qualitative methods to support recovery of endangered species: The case of red-cockaded woodpecker foraging habitat}, volume={17}, ISSN={2351-9894}, url={http://dx.doi.org/10.1016/J.GECCO.2019.E00553}, DOI={10.1016/j.gecco.2019.e00553}, abstractNote={Meta-analyses are powerful tools for synthesizing wildlife-habitat relationships, but small sample sizes and complex species-habitat relationships often preclude correlative meta-analyses on endangered species. In this study, we demonstrate qualitative comparative analysis (QCA) as a tool that can reliably synthesize habitat-fitness relationships from small sample sizes for species with narrow habitat requirements. We apply QCA to results from a habitat threshold regression tree model and identify habitat thresholds with consistent positive effects on fitness of the federally endangered red-cockaded woodpecker (Dryobates borealis; RCW) on the Savannah River Site, USA. We reformulated regression tree results in a QCA framework to examine the consistency of threshold effects on RCW fledgling production at the individual group level (n = 47). Synthesizing regression tree results with QCA revealed alternative combinations of habitat thresholds that in conjunction with group size consistently led to above-average fledgling production for 41 of 47 (88%) individual RCW groups. Importantly, QCA identified unique combinations of habitat thresholds and group size related to above-average fledgling production that were not retained in the regression tree model due to small sample sizes. Synthesizing a small habitat-fitness dataset using QCA provided a tractable method to identify unique combinations of habitat and group size conditions that are consistently important to individual fitness, but may not be detected by meta-analyses that can be biased by small sample sizes. QCA offers a viable approach for synthesis of habitat-fitness relationships and can be extended to address many complex issues in endangered species recovery when correlative meta-analyses are not possible.}, journal={Global Ecology and Conservation}, publisher={Elsevier BV}, author={Garabedian, James E. and Peterson, M. Nils and Moorman, Christopher E. and Kilgo, John C.}, year={2019}, month={Jan}, pages={e00553} }
 @article{garabedian_moorman_peterson_kilgo_2018, title={Evaluating interactions between space-use sharing and defence under increasing density conditions for the group-territorial Red-cockaded Woodpecker Leuconotopicus borealis}, volume={160}, ISSN={["1474-919X"]}, DOI={10.1111/ibi.12576}, abstractNote={Information about how bird species respond to increasing density conditions through either space‐use sharing or increased territoriality, and how those changes affect fitness, is essential for effective conservation planning. We used a case study of endangered Red‐cockaded Woodpeckers Leuconotopicus borealis (RCW) to address these questions. We documented over 36 000 locations from 44 RCW groups in three density conditions on two sites in South Carolina, USA, between April 2013 and March 2015. The frequency of neighbouring group interactions differed among density conditions and was highest for high‐density groups. RCW home‐ranges and core‐areas were larger under low‐density conditions ( = 88.4 ha,  = 21.0 ha) than under medium ( = 68.29 ha,  = 16.6 ha) and high‐density ( = 76.3 ha,  = 18.6 ha) conditions. Neighbouring RCWs maintained overlapping home‐ranges with nearly exclusive core‐areas across density conditions, but overlap tended to increase as neighbouring group density increased. Under high‐density conditions, home‐range overlap correlated inversely with clutch size (β ± se = −0.19 ± 0.09), nestling production (β ± se = −0.37 ± 0.09) and fledgling production (β ± se = −0.34 ± 0.08). Our results indicate that RCWs dedicate more effort to territorial defence under high‐density conditions, potentially at the expense of greater foraging efficiency and time allocated to reproduction, as evidenced by reduced fitness. Large home‐range overlap indicated limited territoriality farther away from cavity trees, but the existence of exclusive core‐areas suggests that RCW groups defend habitat closer to cavity trees. Thiessen partitions used to allocate critical foraging habitat offered comprehensive habitat protection for RCW but appear flawed for spatially explicit habitat assessments because they do not accurately delineate space used by individual RCW groups.}, number={4}, journal={IBIS}, author={Garabedian, James E. and Moorman, Christopher E. and Peterson, M. Nils and Kilgo, John C.}, year={2018}, month={Oct}, pages={816–831} }
 @article{champlin_kilgo_gumpertz_moorman_2009, title={Avian Response to Microclimate in Canopy Gaps in a Bottomland Hardwood Forest}, volume={8}, ISSN={["1938-5412"]}, DOI={10.1656/058.008.0110}, abstractNote={Abstract Microclimate may influence use of early successional habitat by birds. We assessed the relationships between avian habitat use and microclimate (temperature, light intensity, and relative humidity) in experimentally created canopy gaps in a bottomland hardwood forest on the Savannah River Site, SC. Gaps were 2- to 3-year-old group-selection timber harvest openings of three sizes (0.13, 0.26, 0.50 ha). Our study was conducted from spring through fall, encompassing four bird-use periods (spring migration, breeding, post-breeding, and fall migration), in 2002 and 2003. We used mist netting and simultaneously recorded microclimate variables to determine the influence of microclimate on bird habitat use. Microclimate was strongly affected by net location within canopy gaps in both years. Temperature generally was higher on the west side of gaps, light intensity was greater in gap centers, and relative humidity was higher on the east side of gaps. However, we found few relationships between bird captures and the microclimate variables. Bird captures were inversely correlated with temperature during the breeding and post-breeding periods in 2002 and positively correlated with temperature during spring 2003. Captures were high where humidity was high during post-breeding 2002, and captures were low where humidity was high during spring 2003. We conclude that variations in the local microclimate had minor influence on avian habitat use within gaps. Instead, habitat selection in relatively mild regions like the southeastern US is based primarily on vegetation structure, while other factors, including microclimate, are less important.}, number={1}, journal={SOUTHEASTERN NATURALIST}, author={Champlin, Tracey B. and Kilgo, John C. and Gumpertz, Marcia L. and Moorman, Christopher E.}, year={2009}, pages={107–120} }
 @article{champlin_kilgo_moorman_2009, title={Food abundance does not determine bird use of early-successional habitat}, volume={90}, ISSN={["1939-9170"]}, DOI={10.1890/08-1190.1}, abstractNote={Few attempts have been made to experimentally address the extent to which temporal or spatial variation in food availability influences avian habitat use. We used an experimental approach to investigate whether bird use differed between treated (arthropods reduced through insecticide application) and control (untreated) forest canopy gaps within a bottomland hardwood forest in the Upper Coastal Plain of South Carolina, USA. Gaps were two‐ to three‐year‐old group selection timber harvest openings of three sizes (0.13, 0.26, and 0.50 ha). Our study was conducted during four bird use periods (spring migration, breeding, post‐breeding, and fall migration) in 2002 and 2003. Arthropods were reduced in treated gaps by 68% in 2002 and 73% in 2003. We used mist‐netting captures and foraging attack rates to assess the influence of arthropod abundance on avian habitat use. Evidence that birds responded to arthropod abundance was limited and inconsistent. In 2002, we generally captured more birds in treated gaps of the smallest size (0.13 ha) and fewer birds in treated gaps of the larger sizes. In 2003, we recorded few differences in the number of captures in treated and control gaps. Foraging attack rates generally were lower in treated than in control gaps, indicating that birds were able to adapt to the reduced food availability and remain in treated gaps. We conclude that arthropod abundance was not a proximate factor controlling whether forest birds used our gaps. The abundance of food resources may not be as important in determining avian habitat selection as previous research has indicated, at least for passerines in temperate subtropical regions.}, number={6}, journal={ECOLOGY}, author={Champlin, Tracey B. and Kilgo, John C. and Moorman, Christopher E.}, year={2009}, month={Jun}, pages={1586–1594} }
 @article{bowen_moorman_kilgo_2007, title={Seasonal bird use of canopy gaps in a bottomland forest}, volume={119}, ISSN={["1938-5447"]}, DOI={10.1676/05-091.1}, abstractNote={Abstract Bird use of small canopy gaps within mature forests has not been well studied, particularly across multiple seasons. We investigated seasonal differences in bird use of gap and forest habitat within a bottomland hardwood forest in the Upper Coastal Plain of South Carolina. Gaps were 0.13- to 0.5-ha, 7- to 8-year-old group-selection timber harvest openings. Our study occurred during four bird-use periods (spring migration, breeding, postbreeding, and fall migration) in 2001 and 2002. We used plot counts and mist netting to estimate bird abundance in canopy gaps and surrounding mature forest habitats. Using both survey methods, we observed more birds, including forest-interior species, forest-edge species, field-edge species, and several individual species in canopy gap and gap-edge habitats than in surrounding mature forest during all periods. Interactions between period and habitat type often were significant in models, suggesting a seasonal shift in habitat use. Bird activity generally shifted between the interior of canopy gaps and the immediate gap edge, but many species increased their use of forested habitat during the breeding period. This suggests that many species of birds selectively choose gap and gap-edge habitat over surrounding mature forest during the non-breeding period. Creation of small canopy gaps within a mature forest may increase local bird species richness. The reasons for increased bird activity in gaps remain unclear.}, number={1}, journal={WILSON JOURNAL OF ORNITHOLOGY}, author={Bowen, Liessa T. and Moorman, Christopher E. and Kilgo, John C.}, year={2007}, month={Mar}, pages={77–88} }
 @article{moorman_bowen_kilgo_sorenson_hanula_horn_ulyshen_2007, title={Seasonal diets of insectivorous birds using canopy gaps in a bottomland forest}, volume={78}, ISSN={["1557-9263"]}, DOI={10.1111/j.1557-9263.2006.00081.x}, abstractNote={Little is known about how insectivorous bird diets are influenced by arthropod availability and about how these relationships vary seasonally. We captured birds in forest-canopy gaps and adjacent mature forest during 2001 and 2002 at the Savannah River Site in Barnwell County, South Carolina, and flushed their crops to gather information about arthropods eaten during four periods: spring migration, breeding, postbreeding, and fall migration. Arthropod availability for foliage- and ground-gleaning birds was examined by leaf clipping and pitfall trapping. Coleopterans and Hemipterans were used by foliage- and ground-gleaners more than expected during all periods, whereas arthropods in the orders Araneae and Hymenoptera were used as, or less than, expected based on availability during all periods. Ground-gleaning birds used Homopterans and Lepidopterans in proportions higher than availability during all periods. Arthropod use by birds was consistent from spring through fall migration, with no apparent seasonal shift in diet. Based on concurrent studies, heavily used orders of arthropods were equally abundant or slightly less abundant in canopy gaps than in the surrounding mature forest, but bird species were most frequently detected in gaps. Such results suggest that preferential feeding on arthropods by foliage-gleaning birds in gap habitats reduced arthropod densities or, alternatively, that bird use of gap and forest habitat was not determined by food resources. The abundance of arthropods across the stand may have allowed birds to remain in the densely vegetated gaps where thick cover provides protection from predators.}, number={1}, journal={JOURNAL OF FIELD ORNITHOLOGY}, author={Moorman, Christopher E. and Bowen, Liessa T. and Kilgo, John C. and Sorenson, Clyde E. and Hanula, James L. and Horn, Scott and Ulyshen, Mike D.}, year={2007}, pages={11–20} }