Long-distant migrants timing their arrival on the breeding grounds face a tradeoff between optimal timing for breeding and optimal timing for survival. For many shorebird species, the flyway northward spans thousands of kilometers, and both conditions encountered en route and priorities of individuals can affect the timing of migration. We used data from spring migration surveys of Western Sandpipers (Calidris mauri) and Pacific Dunlins (Calidris alpina pacifica) along the Pacific Flyway of North America to determine whether the timing of their northward migration changed from 1985 to 2016. We compiled survey data for both species from 6 sites of varying size along the northern portion of the flyway from Washington, USA, through British Columbia, Canada, to Alaska, USA, and estimated interannual trends in the timing of passage through each site. Peak passage dates at the sites closest to the species' breeding grounds in Alaska became later by 1–2 days over the study period, while dates of peak passage at sites farther south became ∼3 days earlier. A post hoc analysis suggested that local temperatures affected peak passage dates at most sites, with warmer temperatures related to earlier passage. Discerning patterns of movement by Dunlins at southern sites was complicated by the presence of winter residents. Simulation analyses of sandpiper movement through a stopover site highlighted both length of stay and timing of arrival as important factors shaping peak passage estimates. We suggest that Western Sandpipers appear to be arriving earlier at southern sites and staying longer at larger stopover sites, such as Alaska's Copper River delta. Our methodology generated specific predictions of peak passage dates on northward migration that may be useful in other systems for which historical count data are available.

Eastern hemlock (Tsuga canadensis) is undergoing widespread decline throughout the eastern United States due to the introduction of the nonnative hemlock woolly adelgid (Adelges tsugae). In light of hemlock's unique significance for avian communities, we examined the long-term response of the breeding bird community to the decline and die-off of this foundational forest species. We conducted variable-radius point counts to survey bird communities in both hemlock and hardwood stands in 2000, during the early stages of adelgid infestation, and again in 2015 and 2016, following significant hemlock decline. We also measured the severity of hemlock decline and associated vegetation variables in the same hemlock stands in which avian surveys were completed. We used multispecies occupancy models to examine species-specific and species group responses to hemlock decline. Results showed that, across hemlock stands, hemlock basal area declined from a mean of 56% of the total basal area to 46%, and that hemlock decline was correlated with current vegetation structure, including an increased deciduous understory. Species richness of hemlock-associated birds declined by an average of ∼1 species per survey location. The Black-throated Green Warbler (Setophaga virens) was the most strongly affected, declining in occupancy by 30%. All other species groups responded positively, with the strongest responses by species associated with the shrub layer, forest edge, and mature deciduous habitat. The species composition in hemlock and hardwood stands became more similar over time as the unique species assemblages in hemlock stands gave way to the avian community of the surrounding hardwood landscape, highlighting a trend toward homogenization of the avian community. Where hemlock-associated bird species persisted, their presence was correlated with a combined effect of greater hemlock basal area and better hemlock condition. Our results demonstrate that the decline of hemlocks has restructured vegetation communities and their associated avian communities over time, with strong implications for forest-specialist birds.

To achieve greater understanding of the full annual cycles of birds, it is critical to describe the spatial nature of little-understood phases. One of the least understood aspects of avian annual cycles is the ecology of molt: the periodic replacement of feathers. While work on the spatial nature of molt in migratory passerines has increasingly found incidences of species and populations completing molt during migration, this work has been limited entirely to prebasic flight feather molt. We examined the prevalence and progression of contour feather molt in a migratory songbird, the Rusty Blackbird (Euphagus carolinus), during spring stopover. We found that 98% of birds exhibited a partial prealternate molt during stopover, primarily in the head region. Furthermore, molt intensity peaked in the middle of the migration period and was negatively associated with fat score. This is the first evidence in the passerine literature of an obligate prealternate molt completed during migration, which is in many ways similar to the molt strategy of a variety of shorebirds (Families Charadriidae and Scolopacidae). These findings could prove crucial to understanding the constraints on spring migration in this declining species. Furthermore, we argue that molt schedules such as those of the Rusty Blackbird and shorebirds should be referred to as “prealternate molt-migration,” broadening the traditional definition of molt-migration beyond prebasic flight feather molt.

The winter range of the Bicknell's Thrush (Catharus bicknelli), a globally vulnerable Nearctic–Neotropical migratory songbird, is restricted to the Greater Antilles. Most birds occur on Hispaniola, where the species exhibits sexual habitat segregation, and where the loss of its preferred wet broadleaf habitats has been severe. Conservation of female-dominated habitats has been identified as a top priority for the species' preservation. During 2010, we conducted standardized field surveys for the Bicknell's Thrush in forests of the Dominican Republic's Cordillera Septentrional, an area of high importance for females. We combined occurrence data with environmental variables to create a model of thrush distribution and habitat selection in the region. Elevation (densities peaked at ∼600 m), aspect (northeastern slopes), the amount of forest cover within 1 km, and forest density best described thrush presence and abundance. As an example of how predictive models of abundance can inform conservation, we used the best model that contained only spatially explicit covariates to map predicted winter abundance of the Bicknell's Thrush. With the highest elevations in the study area (∼600 m) and the most intact forest cover, 2 scientific reserves contained the largest areas of high thrush abundance, but many privately held lands contained forest fragments predicted to contain thrushes. Applying criteria from our abundance model to a region-wide assessment of available private properties, we identified a 400-ha abandoned farm situated along the Cordillera Septentrional between existing protected areas that contained environmental conditions suitable for Bicknell's Thrushes. We used this information to identify, purchase, and create the Dominican Republic's first-ever private reserve, the 400-ha Reserva Privada Zorzal. Our model can be used to identify and prioritize additional lands for conservation of the Bicknell's Thrush in the region. Our approach could also be used elsewhere to make informed conservation decisions.

The most recent comprehensive estimates of Northern Spotted Owl (Strix occidentalis caurina) natal dispersal distances were reported in 2002. Since then, Northern Spotted Owl populations have experienced substantial demographic changes, with potential attendant changes in natal dispersal distances, including temporal or geographic trends. We analyzed the natal dispersal of Northern Spotted Owls during 1985–2012 in Oregon and Washington, USA (n = 1,534 dispersal events), to determine current natal dispersal distances and to evaluate potential trends that may inform management actions. Mean net dispersal distance (natal site to site of first attempted breeding) was 23.8 km ± 19.2 km SD, with females dispersing ∼50% farther than males. Net dispersal distance varied by ecoregion (Washington Coast and Cascades, Washington Eastern Cascades, Oregon Coast Range, Oregon and California Cascades, and Oregon and California Klamath) but declined similarly in all ecoregions over time (∼1 km yr⁻¹). Dispersal direction also varied by ecoregion, following coarse-scale forest habitat configuration, and was bimodal (north–south) in the Oregon Coast Range, south–southwest in the Oregon and California Cascades, and showed little directionality in the Washington Eastern Cascades, Washington Coast and Cascades, and Oregon and California Klamath. Long-distance dispersal events (>50 km) also varied by ecoregion (mean: 62.3–99.5 km), with most long-distance dispersal (8% of dispersers; distances up to 177 km) originating in southern ecoregions. We found no direct relationship between Barred Owl (Strix varia) detections near natal or settling locations and dispersal distance. These findings, particularly the declining trend of dispersal distances, may inform management actions aimed toward conservation of the Northern Spotted Owl.

Savanna and woodland are transitional vegetation communities that have largely disappeared while many early-successional bird species have simultaneously declined in abundance. Pine savanna and woodland are being restored in the Midwest through prescribed fire and tree thinning to create their characteristic open canopy, dense ground layer, and variable shrub cover. Ideally, these restoration strategies for vegetation should also facilitate bird conservation objectives. We determined daily nest survival (DSR) for 6 songbird species, representing both shrub-nesting and canopy-nesting species, in southern Missouri, USA, in 2014 and 2015. We evaluated support for hypotheses relating temporal, vegetation, and management factors to DSR. We predicted that nest survival of the 3 shrub-nesting species (Eastern Towhee [Pipilo erythrophthalmus], Yellow-breasted Chat [Icteria virens], and Prairie Warbler [Setophaga discolor]) would show positive relationships with thinning and fire, but only Yellow-breasted Chat DSR was positively related to tree thinning. However, pooling species into a shrub-nesting guild resulted in a positive relationship of nest survival with tree thinning and a weak relationship with fire. For canopy-nesters, Eastern Wood-Pewee (Contopus virens) and Summer Tanager (Piranga rubra) DSR was negatively related to mean canopy cover, and Pine Warbler (Setophaga pinus) DSR was weakly related to tree density by size class. The canopy-nesting guild had higher DSR in thinned areas with lower basal area and less canopy cover. Our results demonstrate that pine savanna–woodland restoration in Missouri is providing high-quality breeding habitat for both shrub-nesting and canopy-nesting species, some of which are species of conservation concern.

Hawai‘i's forest birds face a number of conservation challenges that, if unaddressed, will likely lead to the extinction of multiple species in the coming decades. Threats include habitat loss, invasive plants, non-native predators, and introduced diseases. Climate change is predicted to increase the geographic extent and intensity of these threats, adding urgency to implementation of tractable conservation strategies. We present a set of actionable research and management approaches, identified by conservation practitioners in Hawai'i, that will be critical for the conservation of Hawaiian forest birds in the coming years. We also summarize recent progress on these conservation priorities. The threats facing Hawai‘i's forest birds are not unique to Hawai‘i, and successful conservation strategies developed in Hawai‘i can serve as a model for other imperiled communities around the world, especially on islands.

The impact of habitat loss on shorebirds may be exacerbated by disturbance from human recreational use, which further reduces the amount of coastal habitat that is functionally available. This can have consequences for the condition of individual birds or for population processes, both of which should be considered in strategies to reduce conflict between shorebirds and recreational users of coastal habitat. Our objectives were to determine the associations between human recreational use, coastal habitat modifications, and Piping Plover (Charadrius melodus) body condition and demography. We monitored banded Piping Plovers throughout their annual cycle to assess variation in body condition, true survival, and site fidelity related to disturbance regimes in 8 geographically proximate, nonbreeding areas along the southeastern Atlantic Coast of North America from 2012 to 2016. Piping Plovers in disturbed sites were 7% lighter than those in less disturbed sites. Additionally, true annual survival was lower in more disturbed areas. However, site fidelity was less influenced by disturbance than were body mass and survival. Movements away from specific nonbreeding areas were uncommon, regardless of disturbance regime, but individuals that moved to new wintering locations had high probabilities of annual survival (S̄ = 0.80) relative to their site-faithful counterparts (S̄ = 0.67). Associations among nonbreeding conditions, body condition, and demography highlight the importance of nonbreeding habitats to annual population dynamics of migratory species. Conservation strategies for Piping Plovers that focus solely on breeding season dynamics may not account for some of the mechanisms that influence demographic rates and population trajectories.

One goal of Habitat Conservation Plans is to protect viable populations of animal species. Management actions included in such plans often focus on vegetation restoration to benefit the target animal species. Yet, such restoration activities are often uninformed by fine-scale animal survey data. Using the California Gnatcatcher (Polioptila californica californica), we demonstrate how survey data can guide restoration toward the goal of improving gnatcatcher viability by identifying habitat conditions most favorable for gnatcatcher occupancy. We found that gnatcatcher presence and colonization probabilities tripled as the coverage of coastal sagebrush (Artemisia californica) increased from 10% to 40%. Coastal sagebrush was more likely to be present at low elevations, and was most closely associated with soil texture of 5%–20% clay, 40%–70% sand, and 20%–40% silt. Higher gnatcatcher extinction probabilities were associated with closed, dense habitat; optimal conditions were between 30% and 40% openness, creating a slightly closed canopy. Open habitat was associated with southern aspects, shallow slopes, and inland areas. An understanding of the soil types and physical parameters of the environment that affect vegetation, especially the amount of coastal sagebrush needed for high gnatcatcher occupancy and colonization rates, will help to define restoration target conditions. Using multiseason, occupancy-based surveys in conjunction with detailed habitat measurements will allow ornithologists and land managers to design powerful restoration prescriptions, even within narrowly defined ecosystems.

Avian species endemic to desert grasslands of North America contend with significant ecological challenges, including monsoonal rains, droughts, and variable temperatures. These birds have evolved physiological and behavioral means of coping with such extremes, but ongoing changes to temperature and precipitation patterns are affecting their breeding phenology, reproductive success, and population growth rates. We examined how seasonal and daily weather conditions and habitat structure were associated with the nest survival of Arizona Grasshopper Sparrows (Ammodramus savannarum ammolegus) in the semidesert and plains grasslands of southeastern Arizona, USA. The mean ± SE daily survival rate (DSR) of nests was 0.960 ± 0.006, corresponding to overall nest success of 46%. The previous season's precipitation, large rain events, and nest concealment were the most important factors explaining DSR. Grasshopper Sparrow nest survival decreased with a wetter previous growing season and with large rain events on previous days. Nests that were more concealed had lower survival rates. There was some evidence that nest survival was lower later in the nesting season. In addition, when nest concealment was included in models, there were positive but weak associations between other vegetation variables and DSR—nests with higher visual obstruction at the nest and nest plot scales, and nests that were farther from shrubs >2 m tall, showed higher survival rates. Predation was the major cause of nest failure, suggesting complex interactions among predation, precipitation, and nest concealment. Further, our findings suggest tradeoffs in the potential effects of future climate change on A. s. ammolegus. The increased frequency of extreme storm events predicted for the region may result in reduced nest survival of A. s. ammolegus, but, conversely, lower seasonal precipitation prior to nesting may positively influence nest survival.

Proper methods for euthanasia are critical for research with birds. Training in these methods is generally required by institutional animal care and use committees for any research that involves handling of birds, even if the intent is for birds to be released into the wild. Rapid cardiac compression (RCC) remains a preferred method for quick euthanasia in field settings but has not been described adequately in the literature. We describe proper application of RCC for euthanasia of small birds. We also provide external cues for a bird as it progresses toward death as well as other considerations when using RCC. Note that RCC is also known as “thoracic compression,” but that term is not biologically accurate and should be abandoned.

Most species are distributed such that their density and occupancy is greatest in one habitat, although they are found in other habitats. For example, a species with a high affinity for forests (its primary habitat) may also use urban areas and shrublands (its alternative habitat), although occupancy of these habitats would be lower. While habitat loss is the main conservation threat for most species, less is known about how changes in primary and alternative habitats impact populations. We used a systematic bird survey of the state of Illinois that spanned the past century to investigate how use of specific habitats was related to population changes. Specifically, we used a hierarchical Bayesian model to investigate the relationship between changes in statewide occupancy (probability a species would occur in a study site) and use of specific habitats (probability a species would be in a specific habitat within our study sites) for 66 species sampled in 1906–1909 and 2006–2008. Changes in the use of alternative habitats, and not primary habitats, was related to overall changes in statewide occupancy. Many species that increased over the past century did so by increasing their use of urban areas, while declining species declined the most in agricultural and grassland areas. Although primary habitats form the core of a species' distribution, alternative habitats may provide opportunities for a species to expand its distribution; conversely, declining species may abandon alternative habitats and contract into primary habitats. Consequently, alternative habitats may play an important role in the future of many species. Understanding this role could be crucial for successful conservation.

Understanding multiple challenges that restrict conservation success is a central task of applied ecology, especially when resources are limited and actions are expensive, such as with reintroduction programs. Simultaneous consideration of multiple hypotheses can expedite identification of factors that most limit conservation success. Since 2001, reintroduction of a migratory population of Whooping Cranes (Grus americana) has been under way in eastern North America. Hatching success, however, has been extremely low. In our study area, in and near Necedah National Wildlife Refuge in central Wisconsin, USA, we simultaneously tested 3 hypotheses explaining poor hatching success: harassment of incubating birds by black flies (Simuliidae), effects of captivity, and inexperience of breeders. When black flies were experimentally suppressed, hatching probability doubled. Daily nest survival for Whooping Cranes was strongly and negatively related to an index of black fly abundance, particularly of Simulium annulus. Daily nest survival was negatively but only weakly related to the number of generations that ancestors of breeding Whooping Cranes had been in captivity and was not related to nesting experience. We also examined whether Whooping Cranes were nesting later to avoid stress from black flies. Phenology shifted earlier with more growing degree days and greater nesting experience and was only weakly related to year. Overall, improved hatching success did not lead to better reproductive success. Although effects of black flies on hatching success can be mitigated through management, such actions would not be adequate to generate satisfactory population growth. Recognition of this limitation was hastened through experimentation.

The Western Atlantic population of Red Knot (Calidris canutus rufa) has undergone dramatic declines in recent decades and conservation biologists have sought to improve knowledge about the species' ecology in an effort to understand these declines. One major information gap has been the lack of a detailed understanding of range and habitat use during the breeding season, when the species is distributed sparsely across the Canadian Arctic. Airborne radio-telemetry surveys of Red Knots tagged in Delaware Bay, New Jersey, were conducted across the south and central Canadian Arctic, from Victoria Island in the west to Baffin Island in the east. Intensive field surveys were conducted on Southampton Island, Nunavut, over successive summer field seasons to locate nesting Red Knots and record characteristics of their nesting habitat. Maximum entropy modeling (Maxent) and geographic information system (GIS) data on environmental characteristics were used to predict Red Knot habitat suitability at 2 spatial scales: nesting site location suitability at the local scale across Southampton Island, and breeding habitat suitability (i.e. both nesting and foraging habitat) at a broader, regional scale across the south and central Canadian Arctic. Comparison of the local and regional scale models with independent validation data (i.e. occurrence data not used in the model calibration), showed both models to be useful predictors of habitat suitability. At both spatial scales, Red Knots were found to prefer sparsely vegetated tundra on sedimentary, primarily limestone, bedrock at elevations below 150 m. Our results suggest that it is highly unlikely that the availability of breeding habitat limits the population size of the subspecies. Regional scale mapping provides the basis for more precise geographic targeting of future survey efforts that will aid in the conservation and management of this threatened species.

The recently discovered Cassia Crossbill (Loxia sinesciuris) occurs only in 2 small, isolated mountain ranges in southern Idaho, USA: the South Hills and the Albion Mountains. The species faces 2 major threats from climate change related to its reliance on seeds of Rocky Mountain lodgepole pine (Pinus contorta latifolia). First, increased numbers of hot summer days (≥32°C) since 2003 apparently caused premature cone opening and seed shedding, leading to reduced seed availability and an 80% decline in Cassia Crossbill densities between 2003 and 2011. Second, climate change is predicted to prevent recruitment and could potentially cause the extirpation of lodgepole pine from the South Hills and Albion Mountains by 2080. This extirpation would cause the extinction of Cassia Crossbills, because they are unable to compete for lodgepole pine seeds elsewhere. Although recent summers with fewer hot days have allowed Cassia Crossbills to recover, determining their status will require using density across habitat types to estimate population size. We estimated the density of Cassia Crossbills at 137 locations and used conditional modeling to evaluate the influence of 12 habitat metrics on the species' habitat use. Cassia Crossbills more commonly used larger, mature lodgepole pine stands, and north-facing slopes where cones experience less insolation and more likely retain seeds despite hot summer days. Their estimated range was 67 km² of lodgepole pine forest, with a population of ∼5,800 individuals (95% confidence interval: 3,100–11,000). Given their restricted distribution, small population, and reliance on mature lodgepole pine, the threats posed to Cassia Crossbills by climate change represent a considerable conservation challenge.

Williamson's Sapsuckers (Sphyrapicus thyroideus) are montane woodpeckers threatened by widespread tree removal activities and climate change. Current forest management plans focus on nesting trees, but the incorporation of foraging trees would lead to a more effective management strategy to mitigate habitat loss for this species. We investigated the selection of foraging trees in forests managed for timber extraction and maintenance of wildlife values using foraging observations of 27 radio-tagged adult Williamson's Sapsuckers during the breeding season in 2 regions (Okanagan and Western) of their limited Canadian range. Characteristics of foraging trees (88% of observations on live trees, 11% on dead trees) differed with foraging mode. Large, live Douglas-firs (Pseudotsuga menziesii; ≥22.5 cm dbh) were used for gleaning and sap feeding on tree trunks in both regions, whereas trees used for trunk pecking were mostly large, senescent western larches (Larix occidentalis) in the Okanagan region and large, dead ponderosa pines (Pinus ponderosa) in the Western region (average dbh = 46 cm). For overall foraging activities, Williamson's Sapsuckers selected large, live Douglas-firs with signs of resin exudation and blistering (pitching), and avoided live lodgepole pines (Pinus contorta), quaking aspens (Populus tremuloides), and ponderosa pines. Larger trees and standing dead conifer trees were reused more often for foraging than smaller and live trees. The quality of Williamson's Sapsucker habitat could decrease over the long term if forest management practices reduce the overall size of trees or alter tree species composition to promote lodgepole pine. Forest management should focus on retaining and promoting large live Douglas-fir trees and large senescent or standing dead conifers (also used for nesting), which can be achieved by using thinning, prescribed fire, partial harvesting, and tree retention strategies.

As nature-based recreation grows in popularity, there is concern for reduced fitness of animals exposed to chronic disturbance by these activities. Golden Eagles (Aquila chrysaetos) and other raptors are sensitive to human recreation near their nests, and managers of these species need strategies to mitigate negative effects. We used simulation models to separate the effects of trail density and configuration, land cover configuration, and volume of human recreation on the effectiveness of 2 trail closure strategies to manage disturbance. We simulated a breeding pair of Golden Eagles at 3 territories with varying degrees of trail density under current and increased levels of human activity. We simulated a baseline scenario, a scenario with a 600 m restrictive buffer around the nest, and a scenario where we closed all but the most popular trails to human recreation. We also conducted a trail-swapping simulation with trail configurations of each territory placed into the land cover of the other territories under current and increased levels of human recreation. This allowed us to isolate the effects of trail density and configuration from land cover configuration on flushing frequency of eagles. We found that for current levels of human recreation, the restrictive buffer was best at reducing flushing of incubating eagles, while closing all but the popular trails was best for foraging eagles. However, management did not mitigate disturbance for trail-swapping simulations, indicating that trail density was the main factor influencing eagle flushing frequency when human recreation was increased. Our results suggest that managers should consider both trail density and the level of human recreation before deciding on mitigation strategies, as approaches that work at lower human activity levels may be ineffective when activity levels increase.