Hawaii's only 2 endemic seabirds, Newell's Shearwater (Puffinus auricularis newelli) and Hawaiian Petrel (Pterodroma sandwichensis), are listed under the United States Endangered Species Act. Threats to both species include light attraction and fallout, collisions with power lines and other structures, predation by invasive animals, and habitat degradation. Both species were assumed to be extirpated from the island of Oahu despite limited survey effort. We used survey data from Kauai (both species) and Maui (Hawaiian Petrel only) to model suitable habitat and light conditions. We then projected this model onto Oahu to identify potential survey sites. From April to September of 2016–2017, we deployed automated acoustic recording units at 13 potentially suitable sites across Oahu. We detected Newell's Shearwaters at 2 sites; one on the leeward slopes of Mount Kaala in the Waianae Mountains and another at Poamoho in the Koolau Mountains. We detected Hawaiian Petrels at one location on the windward slope of Mount Kaala. All 3 sites were in nearly intact native forest with steep slopes. The frequency of detections at these sites suggests that both species are regularly prospecting on Oahu and potentially could be breeding there. If they are breeding, these individuals could represent missing links in the population connectivity of both species among islands. Protecting any remnant breeding populations would be of high conservation value given their recent population declines.

Occupancy models rely on logistic regression approaches that use the logit link function for model fitting. Parameter estimates fitted on the logit scale are frequently back-transformed to the probability scale for interpretation. However, caution is necessary, because back-transformation from the linear logit scale to the bounded probability scale can yield statistical artifacts that could lead to spurious inferences. We discuss one such artifact that we term “phantom interactions”—that is, apparent but false interactions—where the effect size of an additive model parameter, when interpreted on the probability scale, appears to vary depending on the value of other model covariates. A recent paper published in The Condor: Ornithological Applications provides an example of this issue (Lee and Bond 2015). The paper's title and central conclusion state that estimated negative effects of fire and salvage logging on Spotted Owl (Strix occidentalis) site occupancy were large at sites where reproduction did not occur the previous year, but small (or “negligible”) at sites where reproduction did occur the previous year, suggesting breeding owls were resistant to disturbances. This implies the explicit modeling of a breeding state × disturbance interaction, but no interactive effects were present in the model used by the authors. A simple calculation of odds ratios (ORs) using data from the paper shows the modeled effects of fire and salvage logging on owls were, in fact, equivalent regardless of the previous year's reproductive state. Lee and Bond (2015) incorrectly concluded differential effects of fire and salvage logging on breeding versus nonbreeding owls because the effect for breeding owls occurred near a boundary on the probability scale, where a change on the logit corresponded to very small changes in probability. To avoid problematic inference, researchers should use ORs to interpret logistic regression and occupancy models.

Understanding a lspecies' diet can be critical for effective conservation. While several traditional methods for assessing raptor diet exist, many pose inherit biases and often require extensive fieldwork that can limit sample sizes and the geographic scope of studies. This is especially true for species that nest at low densities (e.g., large eagles). Recently, several studies have demonstrated the value of web-sourced photographs in tackling ecological and evolutionary questions. Specialized software (e.g., MORPHIC) has been developed to systematically extract Google Images for this purpose. We used this approach to explore the diet of Martial Eagles (Polemaetus bellicosus). A shortage of prey is one of the proposed hypotheses for recent population declines across their range. Of the 4,872 photographs selected by MORPHIC, 254 were usable (5%). Birds, mammals, and reptiles each contributed similarly to overall identified prey. Helmeted Guineafowl (Numida meleagris) were the most important bird prey identified (12% of overall prey). The 4 most important mammalian prey species were Thompson's gazelle (Eudorcas thomsonii; 5%), impala (Aepyceros melampus; 4%), common duiker (Sylvicapra grimmia; 4%), and banded mongoose (Mungos mungo; 4%). Reptile prey was dominated by monitor lizards (Varanus spp.; 21%). Prey class proportions differed significantly by regions with mammalian prey being more common in eastern Africa and reptile prey being more common in southern Africa. Within South Africa, reptile prey proportion was greater in the east than in the west. These corroborate existing prey composition studies. Prey composition differed between age classes, with adult eagles preying on more birds than non-adults. There was no significant difference in the average estimated prey weight by eagle age or feeding position (ground, perched, or flying). Our results suggest that this approach may offer a useful method to explore the diet for raptor species that are well photographed across their range, at minimal cost and research effort.

Ring-billed Gull (Larus delawarensis) populations have dramatically increased throughout their geographic range with the largest concentrations in the Great Lakes region of Canada and the United States. Large populations of gulls cause conflict with humans at recreational beaches, where their effects on human health and safety include bacteria contamination from gull feces. We used border collies to harass and exclude gulls from beaches in summer 2012 and 2013, then measured gull numbers and Escherichia coli. Dogs were effective at reducing gull numbers by 56–76% during continuous and noncontinuous dog treatment periods. Levels of E. coli were lower on dog-treated beaches, but only during the first half of the summer. Mixed modeling analysis showed presence of dogs was a strong predictor of gull numbers and E. coli levels, with variation among dogs, possibly related to age. Noncontinuous use of dogs, applied within an integrated beach management framework, can provide a nonlethal method for reducing gull use and E. coli levels at recreational beaches.

Woodpeckers (Picidae) are broadly associated with forests but vary in sensitivity to habitat alteration, with some species restricted to mature and old-growth forests, usually because of their foraging or nesting requirements. Roosting sites have rarely been considered a critical resource for woodpecker conservation because nearly all woodpecker species roost year-round in excavated cavities similar to their nest sites. A possible exception is the globally vulnerable Helmeted Woodpecker (Celeus galeatus) of the Atlantic Forest of South America. To determine whether roosting ecology may explain their association with mature forest, we radio-tracked 12 Helmeted Woodpeckers in old-growth and selectively logged forests in Argentina, monitored roost cavities, and provided 9 roost boxes. Unlike other woodpeckers, Helmeted Woodpeckers roosted year-round in decay-formed cavities (n = 21), with perching space above the entrance, in the living trunks of large trees. Adults usually roosted alone, but after nesting (in excavated cavities), each adult roosted with one juvenile in a shared, decay-formed cavity for up to 67 days, implying that cavities need enough space for 2 birds. We did not observe use of roost boxes. Helmeted Woodpeckers travelled up to 1,482 m between nests and roosts, reused roost cavities over multiple years (sometimes changing ownership), and interacted aggressively with other cavity-nesting birds at roost cavities, indicating that suitable cavities are a scarce resource. Because logging is likely to have a strong negative impact on the availability of this resource, we urge managers in the Atlantic Forest region to retain large living trees with decay-formed cavities and to allow more selectively logged areas to become old growth.

Artificial incubation of avian eggs is used in scientific research, conservation, zoo husbandry, and the commercial poultry industry. However, whether artificial incubation negatively impacts post-hatch nestling phenotypes and survival compared to naturally incubated young has not been explicitly tested. Here, we assess whether nestlings artificially incubated as eggs and returned to their natal nest after hatching experienced negative impacts in development, health, and survival. From 2007 to 2017, we measured mass, mass growth rate, tarsus length, tarsus growth rate, external lesions, ejection from the nest, fledging success, and recruitment of Lance-tailed Manakin (Chiroxiphia lanceolata) nestlings from 209 nests where 1 of 2 eggs was artificially incubated, along with 230 unmanipulated nests. We found no statistically significant difference in the development, health, and survival among nestlings artificially incubated as eggs, their naturally incubated nestmates, and nestlings from unmanipulated nests. Our results indicate that artificial incubation can be a safe and effective tool in the study of free-living birds.

The multiscale nature of habitat selection during the breeding season for migratory birds means that core-use areas (e.g., breeding territories) are selected based on their local habitat features, but these may also be influenced in some way by features within a larger-scale landscape. We conducted a reciprocal transplant experiment to test the hypothesis that habitat selection and movements of male American Woodcock (Scolopax minor) in core-use areas during the breeding season depend on the perceived quality of the surrounding landscape. We captured second-year male woodcocks (n = 19) at high- or low-likelihood of use landscapes in Rhode Island, USA, affixed each with a radio transmitter, relocated them to the opposite type of landscape, and then determined if they returned to their original site of capture or remained in the landscape to which they were relocated. Birds captured in high-likelihood landscapes and moved to low-likelihood landscapes generally returned to their original high-likelihood landscape (5/7, 71%), but birds captured in low-likelihood landscapes and moved to high-likelihood landscapes rarely returned to their original low-likelihood landscape (1/12, 8%). These results support the hypothesis that woodcock assess their surroundings relatively rapidly and subsequently make critical settlement decisions based on landscape composition. Given that woodcock choice is predicted by the woodcock-specific resource selection function, these results also provide support for the use of this tool to guide forest management for woodcock.

Adult birds may use the production of offspring as a measure of habitat quality when prospecting for territories, increasing competition for productive territories. We evaluated the impact of breeding success on territory retention of Pacific (Gavia pacifica) and Yellow-billed (G. adamsii) loons in the National Petroleum Reserve-Alaska on the Arctic Coastal Plain of northern Alaska using mark–resight data and multi-state modeling. We also used behavioral observations of brood-rearing adult loons to quantify the frequency of visits by prospecting loons. We hypothesized that increased competition for productive territories would result in a decrease in territory retention rates. Territory retention rates the year following successful breeding attempts were only slightly lower (0.90) than after failed breeding attempts (0.93), and few territories were consistently successful across years. Overall territory retention rates were high (0.92) and similar for both species, suggesting that adults were able to defend their territories successfully. Males had higher territory retention rates than females, but we found no influence of mass (a possible proxy for fighting ability) on territory retention. These observations, coupled with the high frequency of visits by prospecting loons, provide additional evidence that site familiarity may provide advantages to territory holders. Quantifying territory retention behaviors may also inform land management decisions for oil and gas development in areas where loons are present. High territory retention rates, frequency of visits by prospectors, and limited habitat where new territories can be established suggest that breeding habitat in northern Alaska is saturated and may be limiting Yellow-billed Loon populations. In contrast, Pacific Loons attempting to acquire a territory may be able to form new territories on smaller, unoccupied lakes.

Growth and survival of juvenile birds is nutritionally demanding, making the availability of major foods critical to population productivity. Access to nutritious foods for juveniles has important implications because poor foraging conditions during development could result in mortality, or reduced fitness in adulthood. Selection of brood-rearing habitats by female Greater Sage-Grouse (Centrocercus urophasianus) thus has broad implications to survival of juveniles and persistence of populations. Previous research using crop contents demonstrated that invertebrates and forbs comprise the major portion of sage-grouse chick diets for the first few months post-hatch. We coupled stable isotope analysis of feathers and field measurements to quantify chick diet and then correlated that with measures of chick body condition. We sought to reconstruct sage-grouse chick dietary history (2013–2015) using nitrogen stable isotopes to (1) evaluate whether selection of brood-rearing habitats by female sage-grouse was related to chick diet, and (2) assess the relationship between dietary consumption and body condition. Brood-rearing females selected habitats in areas where diet resources occurred in proportion to their availability, with the exception that females selected areas with greater forb abundance 4 weeks after hatch. Diet assimilation by chicks at brood-rearing locations was unrelated to the availability of forbs and invertebrates, but consumption of forbs increased with chick age. Chicks that assimilated proportionally greater amounts of plant-derived nitrogen in their feathers during their first week of life tended to weigh more and have longer wing chords. This relationship was similar between male and female chicks. The importance of quality foods for sage-grouse is well recognized and conservation efforts should aim to maintain functioning sagebrush ecosystems containing adequate brood-rearing habitats for juvenile sage-grouse; there remains a need to identify whether desirable effects are achievable when attempting to improve big sagebrush (Artemisia tridentata) habitats to benefit sage-grouse populations.

For most shorebird species, our understanding of the basic limiting factors and when or where they operate during the annual cycle is currently inadequate to either understand ongoing declines or effectively allocate conservation resources for recovery. Whimbrels (Numenius phaeopus) exhibit delayed recruitment and have low fecundity, and populations with such life-history traits are often vulnerable to increases in adult mortality. We tracked 33 adult Whimbrels with satellite transmitters for 12,802 bird-days to investigate patterns in survival and recorded 16 probable and 5 confirmed mortalities. We used Cox's proportional hazards model to estimate daily hazard rates by season and a Kaplan-Meier product limit estimator to estimate monthly survival. Daily hazard rates varied by season and were 5 times higher during migratory periods (fall and spring migration) compared to stationary periods (winter and breeding). Estimated annualized survivorship was 0.54 ± 0.21 (SE) and on the lower end of the range of 0.8–0.9 believed to be required to maintain a stable population. More than half of the mortality recorded during the study occurred during the fall hunting season and within the last remaining area throughout the Western Hemisphere where significant legal and illegal hunting occurs. One-third of mortality occurred during spring migration either within terminal staging sites or as birds made final movements to breeding grounds. Survival during the migratory periods may have been influenced by the use of transmitters.

All ecological measurements are subject to error; the effects of missed detection (false negatives) are well known, but the effects of mistaken detection (false positives) are less understood. Long-term capture–recapture datasets provide valuable ecological insights and baselines for conservation and management, but where such studies rely on noninvasive re-encounters, such as field-readable color bands, there is the potential to accumulate detection errors as the length of the study and number of tags deployed increases. We investigated the prevalence and effects of misreads in a 10-yr dataset of Red Knots (Calidris canutus rufa) marked with field-readable leg flags in Delaware, USA. We quantified the effects of misreads on survival estimation via a simulation study and evaluated whether removal of individuals only reported once in a year (potential misreads) influenced survival estimation from both simulated datasets and our case study data. We found overall apparent error rates of 0.31% (minimum) to 6.6% (maximum). Observer-specific error rates and the variation among observers both decreased with the number of flags an observer recorded. Our simulation study showed that misreads lead to spurious negative trends in survival over time, particularly for long-term studies. Removing all records in which a flag was only recorded once in a sampling occasion reduced bias and eliminated spurious negative trends in survival but also reduced precision in survival estimates. Without data filtering, we found a slight decrease in Red Knot annual survival probability from 2008 to 2018 (β = -0.043 ± 0.03), but removing all single-observation records resulted in no apparent trend (β = -0.0074 ± 0.02). Spurious trends in demographic rates could influence inference about population trajectories and resultant conservation decision-making. Data filtering could eliminate errors, but researchers should carefully consider the tradeoff between precision obtained by larger sample sizes and potential bias due to misreads in their data.

Throughout western North America, longer, hotter fire seasons and dense fuels are yielding more frequent, larger, and higher-severity wildfires, including uncharacteristically large “megafires.” Wildlife species associated with late-seral forest characteristics may be particularly vulnerable to habitat loss stemming from changing fire regimes. The Great Gray Owl (Strix nebulosa) is a state-listed endangered species in California that typically nests in large snags in well-shaded forests adjacent to montane meadows. The 2013 Rim Fire burned 104,000 ha in Yosemite National Park and Stanislaus National Forest, making it the largest recorded fire in California's Sierra Nevada. The fire perimeter contained 23 meadows known to be occupied by Great Gray Owls during the decade prior to the fire, representing nearly a quarter of all known or suspected territories in California at the time. We analyzed 13 yr (2004–2016) of Great Gray Owl detection/non-detection data from 144 meadows in the central Sierra Nevada, including meadows inside and outside the Rim Fire perimeter in Yosemite National Park and on Stanislaus National Forest. During 3 yr of surveys after the fire, Great Gray Owls were detected at 21 of 22 meadows surveyed within the fire perimeter that were occupied during the decade prior to the fire. Bayesian hierarchical modeling revealed that, rather than decreasing after the fire, persistence of owls at meadows actually increased on both National Park Service (NPS) and non-NPS lands, while colonization rates exhibited no significant change. Within the burned area, these dynamics were unrelated to forest structure variables describing post-fire stands around individual meadows. Notably, post-fire increases in owl persistence occurred both inside and outside the fire perimeter, suggesting factors other than the fire were likely favorable to Great Gray Owls during the post-fire years. Great Gray Owls appear to have been largely resilient to effects of the Rim Fire during the 3 yr after it burned.

Maintenance of genetic diversity is important for conserving species, especially those with fragmented habitats or ranges. In the absence of natural dispersal, translocation can be used to achieve this goal, although the success of translocation can be difficult to measure. Here we evaluate genetic change following translocation in Gunnison Sage-Grouse (Centrocercus minimus), a species reduced to 7 discrete populations with low levels of gene flow and high levels of genetic differentiation. Between 2000 and 2014, 306 birds from the largest and most genetically diverse population (Gunnison Basin) were translocated to 5 much smaller satellite populations to augment local population size and increase genetic diversity. Although the magnitude of the effect varied by population, we found evidence of increased genetic variation, decreased genetic differentiation from Gunnison Basin, and reproduction between translocated individuals and resident birds. These results suggest that translocations are impacting satellite populations, with current data providing a new baseline for genetic diversity among populations of this imperiled species.

Globally limited to 45,000 km², salt marshes and their endemic species are threatened by numerous anthropogenic influences, including sea-level rise and predator pressure on survival and nesting success. Along the Atlantic coast of North America, Seaside (Ammospiza maritima) and Saltmarsh (A. caudacuta) sparrows are endemic to salt marshes, with Saltmarsh Sparrows declining by 9% annually. Because vital rates and factors affecting population persistence vary for both species, local estimates are necessary to best predict population persistence in response to management actions. We used a metapopulation model to estimate the population viability of the breeding Seaside and Saltmarsh sparrow populations in coastal New Jersey over a 42-yr period. We incorporated empirical data on the vital rates and abundances of these populations and simulated the effect of low (0.35 m) and high (0.75 m) levels of sea-level rise. We found that the Seaside Sparrow population persisted under both sea-level rise scenarios; however, the Saltmarsh Sparrow population reached a quasi-extinction threshold within 20 yr. Using the same framework, we modeled potential management scenarios that could increase the persistence probability of Saltmarsh Sparrows and found that fecundity and juvenile survival rates will require at least a 15% concurrent increase for the local population to persist beyond 2050. Future field research should evaluate the feasibility and effectiveness of management actions, such as predator control, for increasing Saltmarsh Sparrow vital rates in order to maintain the species in coastal New Jersey.

Road edges in the temperate zone often negatively affect reproductive success, post-fledging survival, and dispersal of forest birds through processes associated with edge habitats. This pattern is less clear in the tropics due to a lack of studies using natural nests and radio-tagged fledglings as well as an almost complete absence of information on nest and fledgling predators. We investigated the influence of road edge on nest success, post-fledging survival, and dispersal of White-rumped Shama (Copsychus malabaricus) in a dry evergreen forest in northeastern Thailand. One hundred nest boxes were placed in forest interior (≥1,000 m from edge of a 5-lane highway) and 100 near forest edge (≤200 m) to assess nesting success. We radio-tracked 50 fledglings from these boxes, 25 each for edge and interior, for 7 weeks after fledging. Nest success and post-fledging survival were 11.6% and 23.6% higher at the edge versus the interior. Predation had the strongest influence on survival, accounting for 100% of nest and 94% of fledgling mortality. Fledglings used locations with denser understory vegetation cover relative to the available habitat, probably to reduce predation risk. Green cat snake (Boiga cyanea) and northern pig-tailed macaque (Macaca leonina), which likely prefer forest interiors over edges, were the primary predators of nests and fledglings in this landscape. There were no significant differences in timing of dispersal and dispersal distance or dispersal direction in relation to proximity to edge. Our results suggest that the impacts of edge effects on the reproductive success of birds appear to be strongly dependent on the habitat preferences of locally dominant predators. Further research will be needed to identify key predators and broadly assess their foraging behaviors in individual landscapes.

Natural resource managers are increasingly applying tree reduction treatments to piñon–juniper woodlands to meet a range of ecological, social, and economic goals. However, treatment effects on woodland-obligate bird species are not well understood. We measured multiscale avian occupancy on 29 paired (control/treatment) sites in piñon–juniper woodlands in central Colorado, USA. We conducted point counts at 232 stations, 3 times each season in 2014 and 2015. We used hierarchical multiscale modeling to obtain unbiased estimates of landscape and local occupancy (i.e. probability of use) in treated and untreated sites for 31 species. Treatments reduced the occupancy of conifer obligates, including Mountain Chickadee (Poecile gambeli), Clark's Nutcracker (Nucifraga columbiana), and White-breasted Nuthatch (Sitta carolinensis), and increased occupancy of Lark Sparrow (Chondestes grammacus) and Mountain Bluebird (Sialia currucoides). Occupancy of Virginia's Warbler (Oreothylpis virginiae) and Gray Flycatcher (Empidonax wrightii), two piñon–juniper specialists, decreased at the landscape scale in treated sites, and Pinyon Jay (Gymnorhinus cyanocephalus) occupancy decreased at the local scale. Tree reduction treatments in piñon–juniper woodlands have the potential to reduce habitat quality for a suite of bird species of conservation concern. We suggest that treatments designed to retain higher tree density and basal area will benefit conifer-obligate and piñon–juniper specialist bird species.

Southern New England provides key wintering habitat for White-winged Scoters (Melanitta fusca). This area has also pioneered the development of offshore wind energy in North America. The U.S. Bureau of Ocean Energy Management (BOEM) has established 9 Wind Energy Area (WEA) lease blocks along the Atlantic Outer Continental Shelf in areas that may provide important staging and wintering habitat for scoters and other species of sea ducks. Concern over the potential impact of offshore wind energy on sea duck populations has led to efforts to develop models to understand their distribution, habitat use, and site fidelity. We used satellite telemetry to document winter phenology and site fidelity, as well as fine-scale resource selection and habitat use, of 40 White-winged Scoters along the southern New England continental shelf. Scoters spent over half of the annual cycle on the wintering grounds and demonstrated a high degree of interannual site fidelity to composite core-use areas. Sizes of individual 50% core-use home ranges were variable ( = 868 km²; range: 32–4,220 km²) and individual 95% utilization distributions ranged widely ( = 4,388 km²; range: 272–18,235 km²). More than half of all tagged birds occupied 2 or more discrete core-use areas that were up to 400 km apart. Throughout the study area, scoters selected areas with lower salinity, lower sea surface temperature, higher chlorophyll-a concentrations, and higher hard-bottom substrate probability. Resource selection function models classified 18,649 km² (23%) of the study area as high probability of use, which included or immediately bordered ∼420 km² of proposed WEA lease blocks. Future offshore wind energy developments in the region should avoid key habitats highlighted by this study and carefully consider the environmental characteristics selected by sea ducks when planning and siting future WEAs.

Many North American birds associated with forest disturbances such as wildfire and mountain pine beetle (Dendroctonus ponderosae) outbreaks are declining in abundance. More information on relationships between avian abundance and forest structure and disturbance is needed to guide conservation and management. Our objective was to determine densities of American Three-toed Woodpecker (Picoides dorsalis), Black-backed Woodpecker (Picoides arcticus), Red-breasted Nuthatch (Sitta canadensis), Brown Creeper (Certhia americana), and White-winged Junco (Junco hyemalis aikeni) in relation to vegetation characteristics and disturbance at the point and landscape level in the Black Hills and Bear Lodge Mountains of South Dakota and Wyoming. We conducted 3 point counts from late March to late June 2015 and 2016 at more than 2,300 locations distributed across a gradient of forest structure and disturbance types. We estimated densities using 3-level hierarchical time-removal models that simultaneously estimated abundance, availability, and detection probability. Black-backed Woodpeckers were positively related to percent area in 1- to 3-year-old wildfires and Brown Creepers were positively associated with percent area in 4- to 5-year-old wildfires; however, Red-breasted Nuthatches were negatively related to percent area in 3- to 5-year-old wildfires. With the exception of American Three-toed Woodpeckers, species were positively related to percent cover of beetle-killed trees. Brown Creepers, White-winged Juncos, and Red-breasted Nuthatches had mixed responses to percent overstory canopy cover. White-winged Juncos also had a positive association with percent ground vegetation at the point and landscape level. Brown Creepers were strongly linked with spruce vegetation type. American Three-toed Woodpeckers, which are thought to occupy spruce forest in the Black Hills, did not show a strong relationship with any covariates. Maintaining some areas of natural disturbances along with heterogeneity of vegetation characteristics within stands and at the landscape scale will benefit the needs of a diverse bird community in the Black Hills.