Urban areas continue to expand, with cities now containing more than half of the world's population. As cities grow, natural habitat is transformed, changing the face of the local biota and the resources available for it. Wherever woodpeckers are present, the cavities that they excavate provide an important ecological service that facilitates many other species. We studied how the Pileated Woodpecker (Dryocopus pileatus) uses suburban areas. From 2009 to 2013, we used radio-telemetry to determine the annual home range size and habitat use of 13 individuals in 9 suburbs that varied in their level of urbanization (ranging from 5% to 90% forest remaining). We used concentration of use and resource utilization functions to examine vegetative characteristics used by woodpeckers at relatively large (i.e. 1 km²) and more local (i.e. ⅓ ha) scales. The average home range of suburban Pileated Woodpeckers was significantly smaller than expected based on previous studies. Pileated Woodpeckers concentrated their use of the landscape in native coniferous and deciduous forest, as well as in lightly and moderately urbanized areas. Highly urbanized areas were seldom used. For males, resource use increased with increasing mean diameter of dominant hardwood species. Our results suggest that maintaining forest cover above 20% and retaining large deciduous trees and snags in public green spaces and yards may improve the suitability of suburban areas for woodpeckers and the biodiversity that they facilitate.

Nest attendance during incubation is an important facet of avian nesting behavior, and understanding the number, timing, and duration of incubation recesses can improve our understanding of the factors determining avian reproductive success. Temperature loggers are a low-cost, noninvasive method for studying nest attendance, but processing and interpreting the data present logistical challenges for investigators. We developed an accurate automated method for processing data from temperature loggers to identify incubation recesses. This automated method combines absolute changes in nest temperature over time and changes relative to daily nest-specific variation in temperature to identify incubation recesses. We validated this method through comparison with recesses observed during continuous infrared video monitoring of 3 Mallard (Anas platyrhynchos) and 7 Gadwall (Mareca strepera) nests in northern California, USA. Of 116 recesses observed on camera, we detected 102 (88%) with automated recess detection. After excluding 7 recesses in which nest temperature did not decrease during the recess, and which would therefore have been undetectable without ancillary data, we detected 102 of 109 (94%) recesses with automated recess detection. The time lag in detecting a hen's departure from her nest (i.e. when the recess had begun) was influenced by ambient temperature, although detection of the recess itself was not. The lag in detecting the start of a recess was (mean ± SD) 6.9 ± 2.7 min when ambient temperatures were below 30°C, and 13.7 ± 3.2 min at temperatures above 30°C. The lag in detecting the end of a recess was 1.7 ± 3.2 min and was not affected by ambient temperature. Recesses observed on camera were slightly longer (178.3 ± 122.2 min) than those estimated with automated recess detection (158.7 ± 93.1 min), with the time lag in detecting the start of a recess under warm ambient temperatures contributing the most to the difference. These results demonstrate the accuracy of the automated method that we have developed for identifying the timing and duration of incubation recesses using nest temperature data. This method was developed using data from dabbling ducks but is readily adaptable to other avian taxa with appropriate changes in user-defined criteria for identifying incubation recesses.

Agricultural practices have intensified during the past 50 yr, increasing crop production and altering the Canadian prairie landscape by removing or degrading uncropped habitats, including wetlands. We predicted that agricultural practices would alter invertebrate communities and the diets of consumers such as insectivorous birds. Using stable isotope analysis (δ¹³C and δ¹⁵N), we tested for differences in the assimilated diets and isotopic niche widths of adult and nestling Tree Swallows (Tachycineta bicolor) in grassland and cropland sites with similar wetland densities in Saskatchewan, Canada. We also assessed relationships between swallow diet and body size, mass, and condition. Dietary composition and niche width differed between years and age classes but were not consistently related to agricultural land cover. Aquatic insect prey (Diptera and Odonata) made up 75% of all swallow diets, but nestlings consumed a larger proportion of terrestrial Diptera, resulting in broader isotopic niche widths compared with adults. Age-specific dietary differences could have been related to temporal shifts in the insect community or distinct foraging by adults when feeding nestlings. The body mass and condition of adult and nestling swallows were unrelated to diet, but were higher on average in grassland than cropland habitat. Overall, Tree Swallows specialized in feeding on aquatic insects, regardless of agricultural land cover, at least in wetland-dominated habitats. Food resources originating from wetlands may play a critical role in supporting insectivorous bird populations in agricultural landscapes.

We used conventional and finite mixture removal models with and without time-varying covariates to evaluate availability given presence for 152 bird species using data from point counts in boreal North America. We found that the choice of model had an impact on the estimability of unknown model parameters and affected the bias and variance of corrected counts. Finite mixture models provided better fit than conventional removal models and better adjusted for count duration. However, reliably estimating parameters and minimizing variance using mixture models required at least 200–1,000 detections. Mixture models with time-varying proportions of infrequent singers were best supported across species, indicating that accounting for date- and time-related heterogeneity is important when combining data across studies over large spatial scales, multiple sampling time frames, or variable survey protocols. Our flexible and continuous time-removal modeling framework can be used to account for such heterogeneity through the incorporation of easily obtainable covariates, such as methods, date, time, and location. Accounting for availability bias in bird surveys allows for better integration of disparate studies at large spatial scales and better adjustment of local, regional, and continental population size estimates.

Wildlife-friendly agricultural practices, such as agroforestry, can play an important role in conserving biodiversity by providing and connecting habitat across working landscapes. Silvopastures (i.e. pastures with substantial tree cover), in particular, possess considerable potential for conserving biodiversity due to the dominance of pastoral landscapes in many regions. However, to balance tradeoffs between the conservation and agricultural values of these anthropogenic systems, better information on wildlife use and how it relates to habitat quality is needed. To improve our mechanistic understanding of silvopastoral habitat quality, and to develop management recommendations, we evaluated the foraging behavior of insectivorous forest birds in Andean silvopastures compared with forest fragments. Focal species' prey attack rates were >25% lower in silvopastures than in forest fragments, suggesting that arthropod prey were less abundant or accessible in silvopastures than in forest fragments. In forest fragments, birds in mixed-species foraging flocks attacked prey more frequently than solitary birds. In silvopastures, flocking and solitary birds attacked prey at similar rates, and birds foraged in flocks half as frequently as in forest fragments. Insectivorous birds preferentially foraged in a small subset of tree genera in forest fragments, but did not exhibit selective foraging in less botanically diverse silvopastures. Insectivorous species that used silvopastures foraged in microhabitats such as vine tangles and hanging dead leaves less frequently than species that did not use silvopastures. Forest species that used silvopastures may have been negatively affected by a breakdown of beneficial interspecific interactions in silvopastures, highlighting the potential for cascading effects of species loss in anthropogenic habitats. Managing silvopastures to include preferred tree species and microhabitats could improve their habitat quality for forest species, but strategies to enhance the conservation value of managed landscapes with silvopastures must also include preservation of forest fragments.

Avian endemism in the Albertine Rift is among the highest of any region in Africa. Conservation of these forests is a high priority, but informed prioritization has been hampered by limited data for most endemic bird species. We employed ecological niche models, coupled with remote sensing and field data, to present a case study of 2 Albertine Rift bush-shrikes (Laniarius) that until recently had been considered conspecific. The ecological niche models are based on presence-only data from museum specimens and sight records from field surveys from the region. We generated a set of competing models with different subsets of environmental variables. We evaluated competing models with an intuitive and broadly applicable model-selection strategy appropriate for assessing suitable habitat for species of conservation concern. Based on its distribution, habitat requirements, and the boundaries of national parks in the Albertine Rift, our results demonstrate that the recently described and cryptic Willard's Sooty Boubou (Laniarius willardi) has lost most of its available habitat within its realized environmental niche and is highly endangered. The Mountain Sooty Boubou (L. poensis) occurs in areas above 2,000 m, where forests are more intact and better protected than mid-elevation forests where L. willardi occurs. These results highlight the plight not only of a recently described species, but also of additional biodiversity confined to mid-elevation forests in the Albertine Rift region.

Information on home range size and movements can inform the design of protected areas for bird species of conservation concern. Populations of the Ocellated Turkey (Meleagris ocellata), a heavily hunted Yucatán endemic, appear to be declining rapidly throughout its small geographic range, despite large protected areas. We radio-tagged adult males during the breeding season in a protected, mixed-use area in Belize to describe individual and annual variation in home range size and use. Our objectives were to (1) determine the minimum reserve area necessary to sustain a population of this species, (2) evaluate use of data from related species for home range parameters in conservation plans, and (3) help design species-specific survey methods suitable for distance sampling and camera trapping. There were no differences in mean minimum convex polygon (969 ha), 95% fixed kernel (692 ha), and 50% fixed kernel (90 ha) due to breeding strategy or habitat disturbance. The core home ranges of some individuals were restricted to either intact forest or pastures. Across the entire study population, >50% of locations were in areas without closed canopy cover, which suggests that this species can use a matrix of forested and agricultural habitat. Available space-use data reveal that most fully protected areas harboring this species are unlikely to meet minimum reserve area requirements if they were to become completely isolated. In comparison to other, similarly sized galliform species, the mean home range of male Ocellated Turkeys is much larger, possibly because of the idiosyncratic requirements of different mating systems. These large home ranges have implications for transect spacing, camera grid characteristics, photo event sampling, and observer movement rates best suited for accurate surveys of Ocellated Turkeys.

Diagnosing causes of population declines requires an understanding of the contributions of demographic vital rates to interannual variability and long-term changes in population size. At Kent Island, New Brunswick, Canada, an isolated population of Tree Swallows (Tachycineta bicolor) collapsed between 1987 and 2010, providing a unique opportunity to reconstruct how demographic rates drive population dynamics. We fit an integrated population model to 24 yr of population count, reproductive success, and capture–recapture data to generate annual estimates of productivity, juvenile and adult survival, immigration, and the finite rate of population change (λ). The Kent Island population declined from 202 to 12 breeding adults over 24 yr, with a geometric mean decline of 11.6% per year. Annual apparent survival of adults averaged 56% across sexes, whereas annual survival and recruitment of juveniles never exceeded 6%. Transient life table response experiments revealed that variation in male and female immigration rates were the major contributors to both overall and interannual variation in λ, followed by female and male adult survival. Local recruitment and reproductive rates had little effect on variation in λ. Given broad-scale regional declines in Tree Swallows, our study shows how declines of isolated populations can be driven by reductions in immigration, especially when coupled with variation in adult survival and low local recruitment.

Bird species around the world are threatened with extinction. In North America, aerial insectivores are experiencing particularly severe population declines. To conserve these species, we need to know which life stages have the largest influence on population growth. We monitored a box-nesting population of Tree Swallows (Tachycineta bicolor) from 1975 to 2017. From this long-term dataset, we derived estimates of 9 vital rates: clutch size, reproductive attempts, and overwinter return for 2 age classes of adult females, and hatching, fledging, and juvenile recruitment rates. We conducted a life-stage simulation analysis on this population based on a 3-stage, female-based population projection matrix to determine which of these vital rates had the greatest influence on overall population growth rate. We determined each vital rate's sensitivity (i.e. the effect of a small change in each vital rate on population growth), elasticity (i.e. the effect of a proportional change in each vital rate on population growth), and ability to explain variation in population growth rate. Juvenile recruitment, female return for both age classes, and fledging success determine population growth because they have high sensitivity, elasticity, and explained large amounts of variation in population growth rate. Contrary to expectations, the number of nesting attempts, clutch size, and hatch rate have little impact on population growth rate. To stem Tree Swallow decline, and potentially the declines we see across the aerial insectivores, fledging success or overwinter survival must increase.

Deforestation and hunting are the leading human-driven disturbances causing population declines of the vulnerable Great Curassow (Crax rubra) and the near threatened Great Tinamou (Tinamus major). These threats typically co-occur, with synergistic effects. We investigated habitat use of Great Curassows and Great Tinamous in the Matapalo corridor of the Osa Peninsula, southwest Costa Rica, where they are not hunted, to understand whether disturbed habitats can be suitable for these species. We analyzed camera trap data from 56 locations and 5579 trapping days using occupancy modeling. We obtained 195 independent captures of Great Curassows at 33 of 56 locations (59%) and 429 independent captures of Great Tinamous at 37 of 56 locations (66%). Great Curassow occupancy did not vary with habitat type but was negatively influenced by distance from roads and by elevation; detection probability varied with habitat type. Great Tinamou occupancy probability was principally related to habitat type; primary, secondary and plantation forest areas all displayed high occupancy probabilities, but occupancy of agricultural land was low. Our work suggests that secondary-growth forests can offer valuable complementary habitat to assist in the recovery of these declining species, at least when hunting is controlled and intact forests are nearby.

Most of Hawaii's endemic avifauna are species of conservation concern. Some of Hawaii's endangered waterbirds, however, have increased in number as a result of intensive management of wetlands. To inform these conservation efforts, we examined interisland genetic structure and gene flow within 2 Hawaiian endemic waterbirds, the Hawaiian Coot (Fulica alai) and the Hawaiian subspecies of the Common Gallinule (Gallinula galeata sandvicensis), using microsatellite and mitochondrial loci. Hawaiian Coots and Hawaiian Gallinules occupy coastal wetlands and exhibit similar life history characteristics and generation times, although they may differ in dispersal propensity. Mark–resight data for Hawaiian Coot indicate interisland movements, whereas Hawaiian Gallinules are sedentary. Genetic diversity is partitioned across the landscape differently for Hawaiian Coots and Hawaiian Gallinules; patterns of variation are likely influenced by behavioral and ecological mechanisms. Hawaiian Coots exhibit low levels of structure at microsatellite loci (F_ST = 0.029) and high levels of gene flow among islands. Conversely, Hawaiian Gallinules are highly structured across marker types (microsatellite F_ST = 0.205, mtDNA control region F_ST = 0.370, mtDNA ND2 F_ST = 0.087), with restricted recent gene flow. Patterns of gene flow have changed after the population declines in the early to mid-1900s. Gene flow estimates indicate historical dispersal from Kauai to Oahu in both species, while recent estimates show individual Hawaiian Coots dispersing from Oahu and restricted gene flow between islands for the Hawaiian Gallinule. Changes in gene flow through time suggest that patterns of dispersal may be an artifact of the availability of habitat, which may be indirectly associated with the synergistic influences of population density and wetland quality. Despite recent population size increases for both species, continued threats to Hawaiian waterbirds (i.e. nonnative mammalian predators and invasive plants, avian disease, altered hydrology, and saltwater inundation of freshwater wetlands) will likely require continued active management to maintain viable populations.

Insufficient time and funding remain obstacles to collecting data across broad spatial scales on the fine-scale distribution of multiple species, their life histories, and interactions with other species and the environment. This often necessitates the use of focal species to inform conservation and management decisions. We used the systematic conservation-planning software Marxan to assess quantitatively whether a focal species can aid in conservation and management of tidal marsh birds. Using a metric of relative cost in the region and current protected areas, we identified priority areas for conservation of 5 specialist taxa—Clapper Rail (Rallus crepitans), Eastern Willet (Tringa semipalmata semipalmata), Acadian Nelson's Sparrow (Ammospiza nelsoni subvirgatus), Saltmarsh Sparrow (A. caudacuta), and Seaside Sparrow (A. maritima)—that nest primarily in tidal marshes in the northeastern United States. We compared the spatial prioritization of sites and cost-effectiveness of alternative protection scenarios that considered individual species, groups of species, and all species simultaneously to evaluate the appropriateness of a focal-species approach. Scenarios that prioritized areas for conservation based on single-species targets were poorly correlated across species. Scenarios based on Saltmarsh Sparrow conservation were most strongly related (r_s = 0.759) to site prioritizations that considered all 5 tidal marsh specialists simultaneously. When comparing multispecies combinations to prioritizations based on the Saltmarsh Sparrow alone, the estimated costs, area of land protection, and number of individuals of each species protected were similar. These results suggest that no species is a good surrogate for another but that the Saltmarsh Sparrow may be a viable focal species for conservation planning to protect tidal marsh birds as a group. By evaluating protection scenarios for all species, we were able to identify areas where conservation is likely to have little or no effect, which could be as important for decision making as identifying the best sites.