Knowledge of demographics is important in conservation planning for endangered species. We monitored the endangered Golden-cheeked Warbler (Setophaga chrysoparia) at a large, discontinuous preserve in an urbanizing landscape in central Texas, USA, to estimate survival and productivity. We estimated adult male survival using a spatial Cormack-Jolly-Seber model that separated emigration from mortality by incorporating location data from resightings. Annual male survival varied from 0.45 to 0.67 from 2010 to 2015 (posterior mean ± SD = 0.57 ± 0.06). Sixty-seven percent of resighted males moved <100 m among years, but a large minority of males moved far enough across years that dispersal should be accounted for in future survival analyses. Mean predicted seasonal productivity varied from 2.32 to 3.18 fledglings territory⁻¹ from 2011 to 2015 (mean ± SD = 2.46 ± 0.51). Seasonal productivity was best predicted by the proportion of total woodland land cover in a 1 km radius around the annual median location, total edge density in a 1 km radius, and the standard deviation of canopy height in a 100 m radius. Seasonal productivity peaked at high proportions of total woodland cover, and decreased with increasing edge and canopy height standard deviation. Annual trends for survival and productivity were similar; that is, survival and productivity were above or below average in the same years, which could have important implications for population stability. Our estimated demographic rates are within the range of those reported from the best long-term data, from Fort Hood, Texas, and support the need for large patches of nonfragmented, mature woodlands to provide high-quality breeding habitat for this species.

Shale gas development continues to outpace the implementation of best management practices for wildlife affected by development. We examined demographic responses of the Louisiana Waterthrush (Parkesia motacilla) to shale gas development during 2009–2011 and 2013–2015 in a predominantly forested landscape in West Virginia, USA. Forest cover across the study area decreased from 95% in 2008 to 91% in 2015, while the area affected by shale gas development increased from 0.4% to 3.9%. We quantified nest survival and productivity, a source–sink threshold, riparian habitat quality, territory density, and territory length by monitoring 58.1 km of forested headwater streams (n = 14 streams). Across years, we saw annual variability in nest survival, with a general declining trend over time. Of 11 a priori models tested to explain nest survival (n = 280 nests), 4 models that included temporal, habitat, and shale gas covariates were supported, and 2 of these models accounted for most of the variation in daily nest survival rate. After accounting for temporal effects (rainfall, nest age, and time within season), shale gas development had negative effects on nest survival. Population-level nest productivity declined and individual productivity was lower in areas disturbed by shale gas development than in undisturbed areas, and a source–sink threshold suggested that disturbed areas were more at risk of being sink habitat. Riparian habitat quality scores, as measured by a U.S. Environmental Protection Agency index and a waterthrush-specific habitat suitability index, differed by year and were negatively related to the amount of each territory disturbed by shale gas development. Territory density was not related to the amount of shale gas disturbance, but decreased over time as territory lengths increased. Overall, our results suggest a decline in waterthrush site quality as shale gas development increases, despite relatively small site-wide forest loss.

Varying environmental conditions have a strong effect on the reproductive- and feeding-ecology measures of seabirds. We assessed how annual variation in the isotopic niche of foraging adults during the chick-rearing season, the size of at-sea foraging areas, and oceanographic characteristics influenced annual variation in linear growth rate and asymptotic mass of Cape Verde Shearwater (Calonectris edwardsii) chicks in 2013–2015. We also examined correlations between chick growth measures and chlorophyll a concentration (CHL) and sea surface temperature anomaly (SSTa) within the foraging areas of their parents in 2014 and 2015. Oceanographic conditions were unfavorable in 2013, with lower CHL and higher SSTa. In 2013 chicks had a lower asymptotic mass, and foraging adults had a wider isotopic niche, larger at-sea home range, and larger foraging areas, suggesting that poor foraging conditions forced parents to search for prey over a larger area. We did not detect significant relationships between CHL and SSTa within the adults' foraging range or chick growth measures in 2014 and 2015. The relationship between oceanographic conditions and breeding success in Cape Verde Shearwater and other tropical seabirds should be examined further across years with varying environmental conditions, and with GPS tags that monitor the entire nesting period.

American Flamingos (Phoenicopterus ruber) are a cultural icon of Florida, USA, yet their status in Florida has been controversial for nearly a century. There is uncertainty regarding historical baselines and long-term trends in flamingo populations, whether flamingo nesting has occurred in Florida, and whether recent observations are wild birds or escapees from captive populations. We review historical and contemporary information to clarify the status and trends of flamingos in Florida and to lay a scientific foundation for their management. We compile historical information from early naturalists and museum records to describe historical abundance, distribution, and phenology. We show definitive evidence for 19th-century flamingo flocks numbering hundreds to thousands of individuals, with large flocks recorded through the year. Historical flocks were heavily hunted, and there is strong evidence that hunting led to extirpation of the historical population by ∼1900. One plausible description of nesting and 4 egg specimens apparently collected in Florida in the 1880s suggest that flamingos probably nested in Florida, though the evidence is not irrefutable. Citizen science data from 1950 to 2015 reveal directional population increases over this period. Contemporary observations reveal dispersal from a breeding colony in Yucatan, Mexico, to Florida, but no conclusive evidence is available for escapes into wild populations. Recent population increases in Florida are best explained by immigration from expanding nesting populations in the Caribbean, rather than increased numbers of escaped individuals. Resolving the long-standing controversy over the status and origin of Florida's flamingos will help develop appropriate evidence-based management strategies for this species—a culturally significant component of Florida's avifauna.

Understanding how the interplay between social behaviors and habitat structure influences space use is important for conservation of birds in restored habitat. We integrated fine-grained LiDAR-derived habitat data, spatial distribution of cavity trees, and spatially explicit behavioral observations in a multi-scale model to determine the relative importance of conspecific density, intraspecific interactions, and the distribution of cavities on space use by Red-cockaded Woodpeckers (Picoides borealis) on 2 sites in South Carolina, USA. We evaluated candidate models using information theoretic methods. Top scale-specific models included effects of conspecific density and number of cavity tree starts within 200 m of Red-cockaded Woodpecker foraging locations, and effects of the number of intraspecific interactions within 400 m of Red-cockaded Woodpecker foraging locations. The top multi-scale model for 22 of 34 Red-cockaded Woodpecker groups included covariates for the number of groups within 200 m of foraging locations and LiDAR-derived habitat with moderate densities of large pines (Pinus spp.) and minimal hardwood overstory. These results indicate distribution of neighboring groups was the most important predictor of space use once a minimal set of structural habitat thresholds was reached, and that placing recruitment clusters as little as 400 m from foraging partitions of neighboring groups may promote establishment of new breeding groups in unoccupied habitat. The presence of neighboring groups likely provides cues to foraging Red-cockaded Woodpeckers that facilitate prospecting prior to juvenile dispersal and, to a lesser extent, indicates high-quality forage resources. Careful consideration of local distribution of neighboring groups in potential habitat may improve managers' ability to increase Red-cockaded Woodpecker density on restored landscapes and mitigate isolation of Red-cockaded Woodpecker groups, a problem that negatively affects fitness across the species' range.

Painted Buntings (Passerina ciris) have been declining in the southeastern United States since the 1970s. A recent demographic assessment highlighted the importance of estimating demographic parameters, which have received little attention to date. The dearth of information is troublesome because attempts to reverse declining trends require a better understanding of the relationship between habitat quality and age- and sex-specific survival and recruitment rates. We used capture–mark–recapture data collected from 2007 to 2015 on Bald Head Island (BHI) and at Hammocks Beach State Park (HBSP) in North Carolina, USA, to estimate local age- and sex-specific annual survival rates and local population size and recruitment rates using programs MARK and LOLASURVIV. Juveniles had lower local survival rates than adults (HBSP: 0.28 ± 0.14 vs. 0.67 ± 0.06; BHI: 0.28 ± 0.04 vs. 0.57 ± 0.02). Local annual survival rates for males on BHI (0.50 ± 0.03) were lower than those for females (0.57 ± 0.02). Age-specific differences were consistent with known differential age-dependent survival skills, and sex-specific differences were consistent with the potential influence of sexual dichromism. Conservative estimates of population size on BHI averaged 101 juveniles and 263 adults annually. Annual in situ reproductive recruitment averaged 28 individuals plus an additional 120 new immigrants, indicating successful reproduction and connectivity with neighboring coastal populations. Local adult survival estimates from our 2 North Carolinian study populations were similar to high-end estimates from across the eastern and western range of the species (∼0.60). Finite observed population growth rate estimates between the BHI population (λ = 1.10) and a South Carolinian population (λ = 0.87) underscore the potential role of differential habitat quality and the importance of information from multiple sites, including nonbreeding grounds, for proper inferences about the status of the species. Reported vital rates provide a stronger foundation on which to base habitat quality as assessed with demographic parameters and to guide Painted Bunting conservation regionally.

Wind power is a fast-growing energy resource, but wind turbines can kill volant wildlife, and the flight behavior of obligate soaring birds can place them at risk of collision with these structures. We analyzed altitudinal data from GPS telemetry of critically endangered California Condors (Gymnogyps californianus) to assess the circumstances under which their flight behavior may place them at risk from collision with wind turbines. Condor flight behavior was strongly influenced by topography and land cover, and birds flew at lower altitudes and closer to the rotor-swept zone of wind turbines when over ridgelines and steep slopes and over forested and grassland cover types. Condor flight behavior was temporally predictable, and birds flew lower and closer to the rotor-swept zone during early morning and evening hours and during the winter months, when thermal updrafts were weakest. Although condors only occasionally flew at altitudes that placed them in the rotor-swept zone of turbines, they regularly flew near or within wind resource areas preferred by energy developers. Practitioners aiming to mitigate collision risk to this and other soaring bird species of conservation concern can consider the manner in which flight behavior varies temporally and in response to areas of high topographic relief and proximity to nocturnal roosting sites. By contrast, collision risk to large soaring birds from turbines should be relatively lower over flatter and less rugged areas and in habitat used during daytime soaring.

The Whooping Crane (Grus americana) is a federally endangered species in the United States and Canada that relies on wetland, grassland, and cropland habitat during its long migration between wintering grounds in coastal Texas, USA, and breeding sites in Alberta and Northwest Territories, Canada. We combined opportunistic Whooping Crane sightings with landscape data to identify correlates of Whooping Crane occurrence along the migration corridor in North Dakota and South Dakota, USA. Whooping Cranes selected landscapes characterized by diverse wetland communities and upland foraging opportunities. Model performance substantially improved when variables related to detection were included, emphasizing the importance of accounting for biases associated with detection and reporting of birds in opportunistic datasets. We created a predictive map showing relative probability of occurrence across the study region by applying our model to GIS data layers; validation using independent, unbiased locations from birds equipped with platform transmitting terminals indicated that our final model adequately predicted habitat use by migrant Whooping Cranes. The probability map demonstrated that existing conservation efforts have protected much top-tier Whooping Crane habitat, especially in the portions of North Dakota and South Dakota that lie east of the Missouri River. Our results can support species recovery by informing prioritization for acquisition and restoration of landscapes that provide safe roosting and foraging habitats. Our results can also guide the siting of structures such as wind towers and electrical transmission and distribution lines, which pose a strike and mortality risk to migrating Whooping Cranes.

Understanding spatial connectivity of long-distance migrants is important for effective management and conservation of both game and nongame species. Hunting of Nearctic-breeding shorebirds occurs in the Caribbean and northern South America; however, the origins of harvested individuals are generally unknown. We used stable hydrogen isotopes (δ²H) in feathers of juvenile shorebirds to infer the origins of birds harvested at 2 sites in Barbados using probabilistic assignments based on a terrestrial–freshwater δ²H isoscape. We used tissue δ¹³C and δ¹⁵N values to filter individuals that had derived nutrients from marine sources. Natal origins of juvenile American Golden-Plover (Pluvialis dominica), Stilt Sandpiper (Calidris himantopus), Short-billed Dowitcher (Limnodromus griseus), and Lesser Yellowlegs (Tringa flavipes) were predicted to be mainly from the eastern parts of their breeding ranges in eastern Canada, with American Golden-Plover, Stilt Sandpiper, and Short-billed Dowitcher also having high potential areas of origin in parts of Alaska, USA. Results from our study should help to modify prior estimates of sustainable harvest levels for these species. We identify sources of uncertainty in determining shorebird origins using stable isotopes, including a lack of shorebird-specific calibration equations and the apparent lack of an appropriate tissue for breeding ground assignment for adults.

Environmental and anthropogenic influences in the marine environment are primary drivers of behavior and demographic outcomes for marine birds. We examined factors influencing the foraging patterns of the Westland Petrel (Procellaria westlandica), a highly threatened, endemic petrel that inhabits subtropical water masses primarily in the Tasman Sea, with a poorly known at-sea distribution. Risk assessments place the species at moderate risk of population impacts from fisheries-related mortality. Studies in the 1990s indicated that trawl fisheries would have an important influence on the Westland Petrel's foraging behavior. We investigated the influence of climatic conditions, marine productivity, bathymetry, the core fishery zone, concurrent fishing activity, light conditions, sex, and breeding stage on Westland Petrel foraging patterns. We analyzed the stable isotopes of carbon and nitrogen from blood sampled during the incubation period and examined changes in isotopic niche width over a 6-yr period. We found that the Westland Petrel's foraging zone varied only slightly between years and that the location of intensively used areas was strongly influenced by bathymetric slope and latitude, and negatively influenced by chlorophyll-a. The core fishery zone had a secondary influence, suggesting that these petrels co-occur with fisheries, but are not dependent on waste for food. Trophic niche width was significantly wider during strong El Niño conditions, indicating that food type, rather than location, was most affected by climatic variation. Consistent use of one marine area across varying times and conditions increases the risk of adverse effects of climate or human-induced impacts on the species. However, marine spatial management tools become viable in these conditions. Further, with rapid increases in sea surface temperatures and extreme values recorded in the region in recent periods, changes to fisheries zones and distributions of natural prey of the species are likely to occur and may change the population's sustainability.

Ocean warming events are becoming more frequent, with potential consequences for birds that use marine resources. We analyzed the annual population growth of Heermann's Gulls (Larus heermanni) through matrix-based demographic models under normal and high sea surface temperature (SST) conditions. Under stable, normal conditions, predicted population growth was ∼4%, with survival of fledglings and juveniles contributing to population growth. Under high SST conditions, predicted population growth dropped to −15% and adult survival became the key factor determining species fitness. Simulations showed a declining growth rate as the frequency of warm SST anomalies increased. Heermann's Gulls can resist oceanographic anomalies of up to 1 event every 5 yr without seriously compromising their population growth rate or their individual fitness, but populations may decline rapidly if the frequency of warm-phase anomalies continues to increase, as it has done during the last decade.

Vegetation structure is a potentially important ecological factor structuring bird communities, but can also affect bird detectability, which can complicate the resolution of ecological patterns. We addressed how vegetation structure may bias the efficiency of the 3 methods most commonly used to sample bird species richness in the Brazilian savanna (Cerrado), which features a gradient of vegetation structure from grasslands to woodlands. We compiled secondary data on Cerrado bird species richness from the scientific literature, master's theses, doctoral dissertations, and regionally important biological publications. We used generalized linear mixed models (GLMM) to analyze the effects of habitat type and sampling method on Cerrado bird species richness estimates, controlling for variation among publications, researchers, and study sites. The data provided strong support for interactive effects between habitat type and sampling method on observed bird species richness. Point count surveys had a greater average number of species sampled per unit time in all habitats, especially in shrublands and grasslands. The number of species sampled per unit time by transect surveys did not vary across the vegetation gradient. Mist net surveys showed a slight decrease in species numbers sampled with increasing vegetation complexity. Random effects accounted for 40% of data variation, mainly because of methodological differences among studies. Despite the amount of work that has been done in the Cerrado, it is not currently possible to ascertain the relationship between bird species richness and vegetation structure because of the interaction between sampling method and vegetation complexity, as well other factors leading to variation among studies. We suggest that estimating detectability is a feasible solution for studies in which the ecological effect of interest also strongly affects sampling, as is the case in the Cerrado.

Recent advancements in information technology and data acquisition have created both new research opportunities and new challenges for using big data in ornithology. We provide an overview of the past, present, and future of big data in ornithology, and explore the rewards and risks associated with their application. Structured data resources (e.g., North American Breeding Bird Survey) continue to play an important role in advancing our understanding of bird population ecology, and the recent advent of semistructured (e.g., eBird) and unstructured (e.g., weather surveillance radar) big data resources has promoted the development of new empirical perspectives that are generating novel insights. For example, big data have been used to study and model bird diversity and distributions across space and time, explore the patterns and determinants of broad-scale migration strategies, and examine the dynamics and mechanisms associated with geographic and phenological responses to global change. The application of big data also holds a number of challenges wherein high data volume and dimensionality can result in noise accumulation, spurious correlations, and incidental endogeneity. In total, big data resources continue to add empirical breadth and detail to ornithology, often at very broad spatial extents, but how the challenges underlying this approach can best be mitigated to maximize inferential quality and rigor needs to be carefully considered.

Sex, age, body size, and breeding origin can influence the nonbreeding distribution of long-distance migratory birds. At continental scales, differential migration can lead to segregation of various classes or populations among different regions. At local scales, class segregation can occur among habitats of differing qualities, often due to dominance interactions related to sex, age, and body size. Conversion of natural habitats to agriculture in the Neotropics is leading to more birds wintering in modified landscapes. We examined how sex, age, size, and breeding origin influenced the use of 3 land cover types (riparian gallery forest, coastal lagoon vegetation, and agriculture) by wintering migratory Yellow Warblers (Setophaga petechia) in western Mexico. Between 2012 and 2014, we used point counts in 6 study sites to estimate Yellow Warbler densities, and we captured, sexed, and aged 205 birds to characterize individuals using each land cover type. Breeding origin was inferred using stable hydrogen isotope ratios (δ²H) in feathers. Contrary to our expectations, Yellow Warbler densities were highest in agricultural sites (5.6 ± 0.7 SE birds ha⁻¹) and lower in sites with natural land cover (riparian gallery forest: 3.6 ± 0.5 birds ha⁻¹; scrub mangrove: 2.0 ± 0.4 birds ha⁻¹). The Yellow Warbler population wintering in our study sites was male-biased (64%), and the use of sites with natural vs. agricultural land cover was not influenced by sex, age, or size of individuals, suggesting that competitive interactions are not limiting access to sites with different land cover. We found that females from more northerly breeding or natal origins were more likely to winter in sites with natural land cover, while females from more southerly origins were more likely to use agricultural sites. Our results suggest that localized population declines could occur via survival differences or carryover effects if condition or subsequent reproductive success differs between birds wintering in sites with natural vs. agricultural land cover.

The “umbrella species” concept is a conservation strategy in which creating and managing reserve areas to meet the needs of one species is thought to benefit other species indirectly. Broad-scale habitat protections on behalf of an umbrella species are assumed to benefit co-occurring taxa, but targeted management actions to improve local habitat suitability for the umbrella species may produce unintended effects on other species. Our objective was to quantify the effects of a common habitat treatment (mowing of big sagebrush [Artemisia tridentata]) intended to benefit a high-profile umbrella species (Greater Sage-Grouse [Centrocercus urophasianus]) on 3 sympatric songbird species of concern. We used a before–after control-impact experimental design spanning 3 yr in Wyoming, USA, to quantify the effect of mowing on the abundance, nest-site selection, nestling condition, and nest survival of 2 sagebrush-obligate songbirds (Brewer's Sparrow [Spizella breweri] and Sage Thrasher [Oreoscoptes montanus]) and one open-habitat generalist songbird (Vesper Sparrow [Pooecetes gramineus]). Mowing was associated with lower abundance of Brewer's Sparrows and Sage Thrashers but higher abundance of Vesper Sparrows. We found no Brewer's Sparrows or Sage Thrashers nesting in the mowed footprint posttreatment, which suggests complete loss of nesting habitat for these species. Mowing was associated with higher nestling condition and nest survival for Vesper Sparrows but not for the sagebrush-obligate species. Management prescriptions that remove woody biomass within a mosaic of intact habitat may be tolerated by sagebrush-obligate songbirds but are likely more beneficial for open-habitat generalist species. By definition, umbrella species conservation entails habitat protections at broad spatial scales. We caution that habitat manipulations to benefit Greater Sage-Grouse could negatively affect nontarget species of conservation concern if implemented across large spatial extents.