@article{palmer_wellendorf_gillis_bromley_2005, title={Effect of field borders and nest-predator reduction on abundance of northern bobwhites}, volume={33}, ISSN={["1938-5463"]}, DOI={10.2193/0091-7648(2005)33[1398:EOFBAN]2.0.CO;2}, abstractNote={Abstract Fallow-field borders along edges of crop fields have been promoted for increasing northern bobwhites (Colinus virginianus) on farms and are a component of recovery plans for this species. However, research on bobwhite population response to field-border practices is sparse. Previous research on 2 farms documented increased use of farm fields and greater reproduction by bobwhites on farms with field borders, but nesting success was low during May and June. Bobwhite population response to field-border practices may increase when they are combined with nest-predator reduction on farms. Effect of nest-predator reduction on bobwhite populations on farmed landscapes has not been investigated in the Southeast. Therefore, we tested the effects of field borders and mesomammal nest-predator reduction on bobwhite abundance on 12 farms in eastern North Carolina, 1997–1999. We applied treatments to farms as factorial combinations. Reduction of mesomammal nest predators, including raccoons (Procyon lotor), Virginia opossums (Didelphis virginiana), and foxes (Urocyon cinereoargenteus and Vulpes vulpes), occurred from February–May of each year. To assess bobwhite response to treatments, we measured summer abundance of males using variable-radius point counts and covey abundance on farms in September and October using morning covey-call surveys. Bobwhites were more abundant on farms with field borders during summer (P=0.08). On field-border farms we heard 1.8× the number of coveys heard on farms without field borders (P=0.004). Summer abundance of bobwhites did not differ as a result of predator reductions (P=0.37), and we heard slightly fewer coveys on predator-reduction farms (P =0.084) during autumn. However, we heard more coveys on farms with both field borders and predator reduction compared to all other farms (P=0.022). Field-border systems were a practical management technique to increase autumn abundance of bobwhites on individual farms in eastern North Carolina.}, number={4}, journal={WILDLIFE SOCIETY BULLETIN}, author={Palmer, WE and Wellendorf, SD and Gillis, JR and Bromley, PT}, year={2005}, pages={1398–1405} }
 @article{wellendorf_palmer_bromley_2004, title={Estimating calling rates of northern bobwhite coveys and measuring abundance}, volume={68}, ISSN={["1937-2817"]}, DOI={10.2193/0022-541X(2004)068[0672:ECRONB]2.0.CO;2}, abstractNote={Abstract Researchers have indexed abundance of the northern bobwhite (Colinus virginianus; hereafter, bobwhite) during autumn by counting the number of coveys heard during early morning call surveys. However, critical assumptions about call rates, survey timing, and seasonality have not been tested, and the effects of weather and bobwhite density on call rates are unknown. Therefore, we quantified covey-calling activity of 219 radiomarked coveys at 5 sites during September–December 1997–1999 to assess the effects of these variables. Across all sites, the average proportion of coveys that called prior to leaving the roost site was 58% (range = 48–87%). Coveys began calling 23.4 ± 0.5 (x̄ ± SE) min before sunrise, and they produced 31.4 ± 1.9 calls/call event; most calls (87%) occurred 35–15 min before sunrise. Using data collected in 1998, we fit 15 logistic regression models to predict the probability of a covey calling. The selected best model (Akaike weight [w] = 0.48) included variables for the number of adjacent calling coveys, wind speed, cloud cover, and barometric pressure change with number of adjacent calling coveys having the greatest effect on covey calling (odds ratio of 1.4). A less parsimonious model, which also included biweekly periods and interaction terms, was potentially as likely (w = 0.41) as the selected model, with the 16–31 October biweekly period having most effect (odds ratio of 1.8) over other biweekly periods. We tested selected best models using observations collected in 1999 from 2 of the sites monitored in 1998. During peak calling periods, predicted call rates were <0.06 from observed covey-call rates. Given the accuracy of predicted call rates, we recommend adjusting covey-call counts by an estimated calling rate to better measure fall bobwhite abundance.}, number={3}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Wellendorf, SD and Palmer, WE and Bromley, PT}, year={2004}, month={Jul}, pages={672–682} }
 @article{palmer_lane_bromley_2001, title={Human-imprinted northern bobwhite chicks and indexing arthropod foods in habitat patches}, volume={65}, ISSN={["1937-2817"]}, DOI={10.2307/3803035}, abstractNote={Arthropods are an important diet resource for northern bobwhite (Colinus virginianus) chicks. Estimates of arthropod abundance using standard entomological sampling techniques may lack biological relevance for assessing potential foraging value of habitat patches because they do not incorporate a realistic availability measure of arthropods to bobwhite chicks. Assuming that human-imprinted (hereafter, imprinted) bobwhite chicks foraged similarly to wild bobwhite chicks, we estimated foraging rates (arthropods [g] consumed/30 min/chick) and mass (g) changes of imprinted chicks foraging in different habitat patches, and used these measures to index arthropod abundance. Ranks of arthropod abundance in soybean fields (n = 8) based on foraging rates of imprinted chicks were different from ranks based on arthropod counts from sweepnet sampling. Ranks of arthropod abundance in soybean fields (n = 10) based on mass changes of imprinted chicks were different from ranks based on dry mass (g) of arthropods collected by sweepnetting and pitfall trapping. However, ranks of habitat patches based on foraging rates and mass changes of imprinted chicks were similar. Estimated sample sizes for comparing chick foraging rates of 2 agricultural habitats, with power (1-β) = 0.8 and α = 0.05, were reasonable (n ≤ 11) at observed levels of sampling error. Foraging rates of imprinted chicks in randomly selected, conventionally tilled soybean and corn fields were low (range 0.09-0.12 g/30 min/chick), but foraging rates were 2.1 and 3.8 times greater along field edges and in no-tilled fields, respectively. Our results suggest that using estimates of arthropod abundance to rank the foraging value of habitats may be unreliable without information on availability of arthropods to chicks. Indices of the foraging value of habitat patches based on imprinted bobwhite chicks were more biologically relevant than arthropod abundance information.}, number={4}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Palmer, WE and Lane, MW and Bromley, PT}, year={2001}, month={Oct}, pages={861–870} }
 @article{marcus_palmer_bromley_2000, title={The effects of farm field borders on overwintering sparrow densities}, volume={112}, ISSN={["0043-5643"]}, DOI={10.1676/0043-5643(2000)112[0517:TEOFFB]2.0.CO;2}, abstractNote={Abstract Wintering birds that use farm fields may benefit from strips of uncultivated, grassy, and weedy vegetation, called field borders. Field borders were established on 4 farms in the North Carolina coastal plain in Wilson and Hyde counties in the spring of 1996. In February of 1997 and 1998, bird numbers on field edges and field interiors, with and without field borders, were surveyed using strip transect and line transect methods. Most (93%) birds detected in field edges were sparrows, including Song (Melospiza melodia), Swamp (Melospiza georgiana), Field (Spizella pusilla), Chipping (Spizella passerina), White-throated (Zonotrichia albicollis), and Savannah (Passerculus sandwichensis) sparrows and Dark-eyed Juncos (Junco hyemalis). We detected more sparrows on farms with field borders than on farms with mowed edges. This difference was most pronounced in field edges where field borders contained 34.5 sparrows/ha and mowed edges contained 12.9 sparrows/ha. Sparrow abundance did not differ by treatment in field interiors. Sparrow density in field borders was intermediate to wintering sparrow densities reported in other studies. These results suggest that establishing field border systems may be an effective way to increase densities of overwintering sparrows on farms in the southeastern U.S. coastal plain.}, number={4}, journal={WILSON BULLETIN}, author={Marcus, JF and Palmer, WE and Bromley, PT}, year={2000}, month={Dec}, pages={517–523} }
 @article{palmer_puckett_anderson_bromley_1998, title={Effects of foliar insecticides on survival of northern bobwhite quail chicks}, volume={62}, ISSN={["1937-2817"]}, DOI={10.2307/3802023}, abstractNote={Reduced survival of chicks may result from exposure to insecticides and may explain declines in northern bobwhite quail (Colinus virginianus) populations on agricultural landscapes. To determine the risk insecticides pose to quail, we quantified exposure rates and hazard, Exposure rate depends on quail habitat use in relation to insecticide applications, whereas hazard depends on susceptibility to a toxin and the dose an individual receives, Because providing early-successional vegetation around row-crop fields is a typical habitat management recommendation, we determined rates of exposure of quail and their broods to insecticides applied to soybean fields with and without vegetated field borders, Radiocollared quail (n = 69) used soybean fields extensively (64% of telemetry locations) at the time of year insecticides were applied. Quail used soybean fields twice as often when vegetated borders surrounded crop fields (P = 0.04). Ten of 18 broods monitored by telemetry were located in soybean fields 88% of the time. In 1993. 4 of 6 broods 0.49). However, ChE activity was depressed (P < 0.001) and body mass was lower (P = 0.02) in chicks exposed to methyl parathion, which historically (pre-1980) received significant use in production of row crops in North Carolina. Our results, along with data on use and toxicity of other insecticides applied to row crops, collectively suggest direct affects to survival of quail chicks from use of foliar-applied insecticides does not explain reduced quail densities on agricultural landscapes.}, number={4}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Palmer, WE and Puckett, KM and Anderson, JR and Bromley, PT}, year={1998}, month={Oct}, pages={1565–1573} }