@article{walters_daniels_carter_doerr_2002, title={Defining quality of red-cockaded woodpecker foraging habitat based on habitat use and fitness}, volume={66}, ISSN={["0022-541X"]}, DOI={10.2307/3802938}, abstractNote={Accurate understanding of habitat quality is a critical component of wildlife management. We developed a definition of high-quality foraging habitat for the red-cockaded woodpecker (Picoides borealis), a federally endangered, cooperatively breeding bird species, from analyses of resource selection and habitat use, relationships between fitness measures and habitat features, and an extensive literature review. In the North Carolina Sandhills, use of foraging habitat at the level of individual trees, habitat patches, and forest stands was strongly and positively related to age and size of pines (Pinus spp.). Use of habitat patches and forest stands was greatest at intermediate densities of medium-sized and large pines and was negatively associated with hardwood and pine midstory. Size of red-cockaded woodpecker groups, an important fitness measure for this species, was positively related to density of old-growth pines within the home range and negatively related to density of medium-sized pines and height of hardwood midstory. Similar results were reported by 2 other studies. High-quality foraging habitat for red-cockaded woodpeckers, therefore, contains sparse or no midstory, intermediate densities of medium-sized and large pines, and old-growth pines in at least low densities. Although we documented a relationship between group size and the amount of habitat meeting our definition of high quality, we were unable to identify the optimum amount of high-quality habitat to provide per group because most study groups had relatively little high-quality foraging habitat. Both fitness and habitat selection in our study population may be constrained by quality and quantity of foraging habitat. James et al. (2001) recommended, and we strongly agree, that foraging habitat be managed for abundant herbaceous ground cover, low densities of small and medium-sized pines, and moderate densities of large pines. We also stress the importance of old-growth pines in foraging habitat. Because the structure of high-quality foraging habitat is similar to that of high-quality nesting habitat, we recommend that management of these 2 be increasingly integrated.}, number={4}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Walters, JR and Daniels, SJ and Carter, JH and Doerr, PD}, year={2002}, month={Oct}, pages={1064–1082} }
 @article{sallabanks_walters_collazo_2000, title={Breeding bird abundance in bottomland hardwood forests: Habitat, edge, and patch size effects}, volume={102}, DOI={10.2307/1370302}, abstractNote={We studied breeding bird communities in extensive bottomland hardwood forests along the lower Roanoke River in North Carolina during 1992 and 1993. We documented a rich avian community and recorded exceptionally high densities of two species (Prothonotary Warbler Protonotaria citrea, Acadian Flycatcher Empidonax virescens), as well as modest densities of three species rarely encountered elsewhere in the region (Cerulean Warbler Dendroica cerulea, Swainson's Warbler Limnothlypis swainsonii, American Redstart Setophaga ruticilla). The effects of patch size and edge on bird abundance were small in this forested landscape, but forest type had a large effect. We found half of the species analyzed to differ in abundance between the two primary habitat types, swamp forest and levee forest. In contrast, no species was consistently more abundant at patch interiors than near edges, and only two forest birds were more common in large compared with small patches. Species analyzed included permanent residents, short-distance migrants, Neotropical migrants, and those identified as forest-interior and area-sensitive species in other studies. Our results suggest that the Roanoke River bottomland forests may be functioning effectively as a reserve for a number of bird species.}, number={4}, journal={Condor}, author={Sallabanks, R. and Walters, J. R. and Collazo, Jaime}, year={2000}, pages={748–758} }
 @article{davenport_lancia_walters_doerr_2000, title={Red-cockaded woodpeckers: a relationship between reproductive fitness and habitat in the North Carolina Sandhills}, volume={28}, number={2}, journal={Wildlife Society Bulletin}, author={Davenport, D. E. and Lancia, R. A. and Walters, J. R. and Doerr, P. D.}, year={2000}, pages={426–434} }
 @article{zwicker_walters_1999, title={Selection of pines for foraging by red-cockaded woodpeckers}, volume={63}, ISSN={["0022-541X"]}, DOI={10.2307/3802797}, abstractNote={Foraging habitat guidelines for the endangered red-cockaded woodpecker (Picoides borealis) are based on properties of stands used by the birds rather than properties of the individual trees selected for foraging. If foraging red-cockaded woodpeckers key in on individual trees, rather than stands, there would be significant implications for optimal management of foraging habitat for this species. We compared age and size of pine trees used by foraging red-cockaded woodpeckers to the age and size of pine trees in the surrounding habitat. We hypothesized that older trees and larger trees would be used more frequently than expected from availability. Mean age of trees used was older than mean age of trees available (P < 0.01), and mean tree size used was larger than mean tree size available (P < 0.05). Our data indicate that 60 years and 25 cm are threshold values where use first exceeds availability, and that old-growth trees (≥ 100 yr old) are strongly selected. The Red-cockaded Woodpecker Recovery Plan stipulates that tree stands 30-60 years old constitute suitable foraging habitat. We found that although red-cockaded woodpeckers foraged on trees 30-49 years old, these trees were used considerably less than their availability. To better reflect habitat selection, foraging guidelines should place more emphasis on trees ≥60 years old, and especially old-growth trees and stands.}, number={3}, journal={JOURNAL OF WILDLIFE MANAGEMENT}, author={Zwicker, SM and Walters, JR}, year={1999}, month={Jul}, pages={843–852} }
 @article{walters_ford_cooper_1999, title={The ecological basis of sensitivity of brown treecreepers to habitat fragmentation: a preliminary assessment}, volume={90}, ISSN={0006-3207}, url={http://dx.doi.org/10.1016/s0006-3207(99)00016-6}, DOI={10.1016/S0006-3207(99)00016-6}, abstractNote={We attempted to identify the mechanisms responsible for adverse effects of habitat fragmentation on brown treecreepers (Climacteris picumnus) inhabiting eucalyptus woodland in northeastern New South Wales, Australia by comparing demography and foraging ecology of birds in highly fragmented and relatively unfragmented landscapes. In particular, we investigated three possibilities, disrupted dispersal due to patch isolation, reduced fecundity due to elevated nest predation, and reduced food availability due to habitat degradation. Nesting success was high in both highly fragmented and less fragmented habitat. Of first nests, 88% were successful, and 60% of successful groups attempted a second brood. However, there were many more groups in the more fragmented habitat than in the less fragmented habitat that lacked a female for most or all of the breeding season, and thus did not attempt nesting (64% vs 13%). In both the more fragmented and the less fragmented habitat, both males and females spent about 70% of their time foraging and 65% of their foraging time on the ground. We reject reduced fecundity in fragmented habitat as an explanation of adverse effects of habitat fragmentation on brown treecreepers. Thus sensitivity to habitat fragmentation has a different basis for this species in this landscape than that suggested for Nearctic-Neotropical migrants in eastern North America. We also reject the possibility of reduced food availability in fragmented habitat. Our data support disrupted dispersal as a likely explanation for the decline of brown treecreepers in fragmented habitat. However, we can not rule out forms of habitat degradation other than reduced food availability.}, number={1}, journal={Biological Conservation}, publisher={Elsevier BV}, author={Walters, Jeffrey R and Ford, Hugh A and Cooper, Caren B}, year={1999}, month={Aug}, pages={13–20} }
 @article{letcher_priddy_walters_crowder_1998, title={An individual-based, spatially-explicit simulation model of the population dynamics of the endangered red-cockaded woodpecker, Picoides borealis}, volume={86}, ISSN={["0006-3207"]}, DOI={10.1016/S0006-3207(98)00019-6}, abstractNote={Spatially-explicit population models allow a link between demography and the landscape. We developed a spatially-explicit simulation model for the red-cockaded woodpecker, Picoides borealis, an endangered and territorial cooperative breeder endemic to the southeastern United States. This kind of model is especially appropriate for this species because it can incorporate the spatial constraints on dispersal of helpers, and because territory locations are predictable. The model combines demographic data from a long-term study with a description of the spatial location of territories. Sensitivity analysis of demographic parameters revealed that population stability was most sensitive to changes in female breeder mortality, mortality of female dispersers and the number of fledglings produced per brood. Population behavior was insensitive to initial stage distribution; reducing the initial number of birds by one-half had a negligible effect. Most importantly, we found that the spatial distribution of territories had as strong an effect on response to demographic stochasticity as territory number. Populations were stable when territories were highly aggregated, with as few as 49 territories. When territories were highly dispersed, more than 169 territories were required to achieve stability. Model results indicate the importance of considering the spatial distribution of territories in management plans, and suggest that this approach is worthy of further development.}, number={1}, journal={BIOLOGICAL CONSERVATION}, author={Letcher, BH and Priddy, JA and Walters, JR and Crowder, LB}, year={1998}, month={Oct}, pages={1–14} }
 @article{dinsmore_collazo_walters_1998, title={Seasonal numbers and distribution of shorebirds on North Carolina's Outer Banks}, volume={110}, number={2}, journal={Wilson Bulletin}, author={Dinsmore, S. J. and Collazo, J. A. and Walters, J. R.}, year={1998}, pages={171–181} }