Anthropogenic developments in marine coastal zones potentially overlap with areas of conservation interest, including important areas for birds. Ideally, spatial patterns of species abundance should be considered at ecologically relevant spatial resolutions (high resolutions) to inform spatial planning and environmental assessments. Most planning so far, however, has relied on coarse-resolution distribution maps from atlas projects or models often based on limited datasets (few surveys), and relationships with environmental variables have rarely been taken into account, leaving many studies and recommendations vulnerable to criticism. We therefore combined the strengths of a detailed database of spatially explicit aerial and ship surveys with high-resolution environmental predictors and species distribution models to predict detailed density patterns for 3 sea duck species, as part of an environmental impact assessment (EIA) in the southern Baltic Sea. We also compared the results from 2 different survey platforms to assess potential differences. We related survey data for Common Eiders (Somateria mollissima), Long-tailed Ducks (Clangula hyemalis), and Common Scoters (Melanitta nigra) to topographic variables, food resources, and anthropogenic pressures using 2-step generalized additive models accounting for zero inflation, nonnormality, and nonlinearity. We accurately predicted distribution patterns (the area under the receiver operating characteristic curve [AUC]: 0.79–0.84) and abundances (Spearman's correlation: 0.36–0.62) at a resolution of 750 m. However, abundance predictions based on aerial survey data differed in magnitude in comparison with predictions from ship survey data, particularly for the frequently diving Long-tailed Duck. We suggest that the main source of the differing abundance estimates was differences in the input data collected using different survey platforms, rather than the modeling approach. A correction factor for birds missed during surveys due to diving activity would therefore increase the accuracy of abundance estimates. Our results show that it is possible to fit ecologically interpretable relationships between species and environmental variables, allowing for the creation of high-resolution predictions useful for management and conservation.

Monitoring animal populations can be difficult. Limited resources often force monitoring programs to rely on unadjusted or smoothed counts as an index of abundance. Smoothing counts is commonly done using a moving-average estimator to dampen sampling variation. These indices are commonly used to inform management decisions, although their reliability is often unknown. We outline a process to evaluate the biological plausibility of annual changes in population counts and indices from a typical monitoring scenario and compare results with a hierarchical Bayesian time series (HBTS) model. We evaluated spring and fall counts, fall indices, and model-based predictions for the Rocky Mountain population (RMP) of Sandhill Cranes (Antigone canadensis) by integrating juvenile recruitment, harvest, and survival into a stochastic stage-based population model. We used simulation to evaluate population indices from the HBTS model and the commonly used 3-yr moving average estimator. We found counts of the RMP to exhibit biologically unrealistic annual change, while the fall population index was largely biologically realistic. HBTS model predictions suggested that the RMP changed little over 31 yr of monitoring, but the pattern depended on assumptions about the observational process. The HBTS model fall population predictions were biologically plausible if observed crane harvest mortality was compensatory up to natural mortality, as empirical evidence suggests. Simulations indicated that the predicted mean of the HBTS model was generally a more reliable estimate of the true population than population indices derived using a moving 3-yr average estimator. Practitioners could gain considerable advantages from modeling population counts using a hierarchical Bayesian autoregressive approach. Advantages would include: (1) obtaining measures of uncertainty; (2) incorporating direct knowledge of the observational and population processes; (3) accommodating missing years of data; and (4) forecasting population size.

Semipalmated Sandpiper (Calidris pusilla) populations have undergone significant declines at core nonbreeding sites in northeastern South America. Breeding populations have also declined in the eastern North American Arctic, but appear to be stable or increasing in the central and western Arctic. To identify vulnerable populations and sites, we documented the migratory connectivity of Semipalmated Sandpipers using light-level geolocators, deploying 250 at 8 Arctic sites across the species' breeding range from 2011 to 2015, plus 87 at a single wintering site in northeastern Brazil in 2013 and 2014. We recovered 59 units and resighted 7 more (26% return rate) on the breeding grounds, but none at the nonbreeding site. We recovered only ∼3% of units deployed in 2013 at eastern Arctic breeding sites, but recovered 33% of those deployed in 2015. Overall, birds with geolocators were 57% as likely to return as those carrying alphanumeric flags. Stopover durations at prairie sites (mean: 8.7 days southbound, 6.7 days northbound) were comparable with durations estimated by local banding studies, but geolocator-tagged birds had longer stopovers than previously estimated at James and Hudson Bay, the Bay of Fundy, and the Gulf of Mexico. Migration routes confirmed an eastern Arctic connection with northeastern South America. Birds from eastern Alaska, USA, and far western Canada wintered from Venezuela to French Guiana. Central Alaskan breeders wintered across a wider range from Ecuador to French Guiana. Birds that bred in western Alaska wintered mainly on the west coasts of Central America and northwestern South America, outside the nonbreeding region in which population declines have been observed. Birds that bred in the eastern Arctic and used the Atlantic Flyway wintered in the areas in South America where declines have been reported, whereas central Arctic–breeding populations were apparently stable. This suggests that declines may be occurring on the Atlantic Flyway and in the eastern Arctic region.

Fecundity, an important demographic variable for wildlife populations, is time consuming and expensive to measure. For seabirds, reproductive success is often estimated from 2 surveys of the colony, 1 during incubation and 1 during chick rearing. Using 33 yr of data on Magellanic Penguins (Spheniscus magellanicus), we compared reproductive success estimated from 2 surveys per season, from infrequent nest checks, and from daily nest checks to answer 4 questions: (1) Is reproductive success estimated from 2 surveys per season accurate enough for population models (within 15% of the ‘true' value)? We found that the answer was yes, if surveys were done on optimal dates and chick counts were adjusted by the percentage of chicks that were heavy enough to fledge. Optimal dates depended on the synchrony and phenology of the species. If penguins bred particularly late or early in a given year, estimates were wrong even if counts were done on the average optimal date. (2) Can counts of occupied nests be adjusted based solely on date? We determined no, not without additional information on egg dates and egg and chick losses. (3) Can long-term trends in reproductive success be detected from 2 surveys per season? Our answer was yes; even using biased data from counts on suboptimal dates, trends with similar slopes were detected using both methods (2 surveys vs. nest checks). (4) How often must nests be checked to get reproductive success estimates comparable with those calculated from daily nest checks? We discovered that checking nests every 2 days was as good as doing daily checks. Reproductive success was overestimated by <5% when checks were conducted every 3–8 days and by <15% (in 90% of years) when checks were done every 9–30 days. The degree of overestimation depended on the timing of nest checks relative to egg laying, loss, and hatching. We conclude that reproductive success can be estimated from 2 surveys, but only if timing, synchrony, and variability of breeding are also known.

Knowledge about interactions between habitat quality and individual condition is vital for understanding ecological processes. We examined variation in commonly used hematological indices and body mass in incubating and chick-rearing Red-necked Grebes (Podiceps grisegena) in Poland breeding under contrasting foraging conditions in ponds used for aquaculture. Grebes used either ponds with low prey availability in the early breeding period and abundant food in the brood-rearing stage (high-quality habitat), or ponds stocked with fish attractive as prey to spring-arriving adults yet later unavailable to chicks due to size constraints (low-quality habitat acting as an ecological trap). Parental effort, measured as the proportion of time allocated to food acquisition and provisioning of chicks, was greater in the low-quality habitat, although adult grebes spent less time foraging there than in the high-quality habitat early in the season. Scaled body mass was higher in incubating grebes than in brood-rearing grebes, regardless of habitat quality. Breeding stage by habitat interactions were significant for hemoglobin, erythrocyte count (RBC), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH), with greater MCV and MCH values (by 20–34%, on average) during brood-rearing than during incubation in the low-quality habitat, and the opposite pattern (by 15–16%) in the high-quality habitat. These hematological responses signify changes in physiological stress associated with parental workloads. Higher MCV and MCH levels (by 22–31%) during the chick-rearing stage in the low-quality compared with the high-quality habitat indicate that parents incurred physiological costs of breeding under ecological trap conditions. No significant effects were found on leucocyte indices (total leucocyte count and heterophil/lymphocyte ratio). We consider the hemoglobin- and RBC-related parameters to be promising indicators of habitat-driven stress associated with prolonged physical exertion, especially when multiple metrics are employed.

Seabirds are of considerable conservation significance due to their key role in ecosystems and their generally high level of threat, especially from invasive species in breeding sites and as a result of bycatch during commercial fishing activities. We examined the genetic diversity, evidence for a bottleneck, and effective population size (N_e) of Red-billed Tropicbirds (Phaethon aethereus) from the Abrolhos Archipelago and White-tailed Tropicbirds (P. lepturus) from Fernando de Noronha Archipelago, both in the southwestern Atlantic Ocean. In addition, intraspecific genetic distance was assessed between 2 Red-billed Tropicbirds breeding on Fernando de Noronha and the larger population on Abrolhos, and between 5 White-tailed Tropicbird individuals breeding on Abrolhos and the breeding population on Fernando de Noronha, to identify relict populations. From 11 microsatellite loci, observed heterozygosity was 0.471 for White-tailed Tropicbirds and 0.267 for Red-billed Tropicbirds. Additionally, N_e was estimated to be as low as 100–200 individuals for each species, ∼25–50% of recent census estimates for the largest population of each species. No deviation from mutation-drift equilibrium was detected, but both species had M-ratios indicative of populations that had experienced a bottleneck or been recently established, and seem to have persisted as small populations over the past few centuries on both archipelagos. Small population size coupled with low evolutionary potential make these populations vulnerable to extinction. In our study sites and worldwide, tropicbirds show slow population growth and vulnerability to introduced predators. These species would benefit from both colony-based management and a better understanding of patterns of genetic diversity within and among populations.

Understanding the catchment areas of key stopover sites for migratory birds is important for their management and conservation. The Saskatchewan River Delta (SRD) in central Canada is North America's largest inland delta and an important spring and fall stopover site for migratory waterfowl, but there is little information on the origins of waterfowl that use the SRD. We used stable isotope analyses of hydrogen (δ²H) and sulfur (δ³⁴S) in feathers of hunter-killed waterfowl on the SRD to infer natal or molt origins of 5 duck species, using spatially explicit assignment to a δ²H feather isoscape developed for waterfowl in North America. Initial classification with δ²H estimated that 50% were migrants from the north and 10% were assigned to regions south of the SRD, leaving only 39% of the sample with origins in the SRD. Using thresholds in feather δ³⁴S values associated with prairie and forest biomes, we further reassigned 64% of SRD birds as having originated from nearby agricultural and forested areas that have similar δ²H values as the delta. Together, these results suggest that >80% of all waterfowl sampled were recent arrivals that were using the SRD as a stopover site. This demonstrates that stable isotope analyses of hunter-killed birds can be used to monitor changes in origins and recruitment into the fall waterfowl population of key stopover sites.

Biotic homogenization—the erosion of biological differences between ecosystems owing to human perturbation—is a trait of the global biodiversity crisis that can affect tropical dry forest biodiversity. We tested whether biotic homogenization was occurring in resident forest bird communities in west-central Mexico. We conducted point-count surveys to assess biotic dissimilarity between resident bird communities in tropical deciduous and oak forests in the upper Balsas River basin across 3 levels of anthropogenic perturbation: primary forest, second-growth forest, and human settlements. We detected a reduction in species richness and taxonomic dissimilarity with increasing anthropogenic effects, due to a directional pattern in which lowland species expanded their elevational distributions up into oak forests. These results point to a need to change agricultural strategies to mitigate impacts on natural vegetation cover and biodiversity.

Light-level geolocators, miniature devices used for tracking avian migration over the full annual cycle, are being widely deployed on small migratory passerines. However, the effects of carrying geolocators on the breeding biology of songbirds are unclear, and variable species- and guild-specific conclusions have been drawn regarding their effects on return rates (apparent annual survival). In particular, there is a lack of published information on the effects of geolocators on Nearctic–Neotropical migrant warblers and canopy-dwelling bird species, which limits our ability to determine whether this technology is appropriate for use on species within these groups. During 2014 and 2015, we deployed geolocators on 49 adult male Cerulean Warblers (Setophaga cerulea) in Pennsylvania, Missouri, and Arkansas, USA. We monitored the effects of geolocators across the full annual cycle by comparing apparent within-breeding-season survival (within-season φ), nestling provisioning rates, nest survival, and return rates between geolocator-tagged adult males and color-banded controls. We found no negative effects of geolocators during the breeding season of geolocator deployment, but the return rate of geolocator-tagged birds was lower than that of control birds (16% ± 5% vs. 35% ± 7%). We found no strong evidence that the differential return rate between the 2 groups was influenced by breeding region, body mass, bird age, year of geolocator deployment, or method of attachment. Although finding no effect of geolocators during the breeding season is encouraging, the lower return rate of geolocator-tagged birds warrants further investigation in the field. If further improvements in the design or attachment methods of geolocators are not technologically possible, the potential for increased mortality (or dispersal) of geolocator-tagged birds should be weighed against the potential conservation gains that could be made by identification of critical stopover, wintering, and breeding habitats for populations of interest.

Identifying sources of annual variation in the reproductive success of a species may provide valuable insights into how the species may be affected by future environmental or climatic conditions. We examined annual variation in the nesting phenology, productivity, and apparent nest success of Mississippi Kites (Ictinia mississippiensis), a species common in urban areas in the southern Great Plains, from May through August. We monitored 498 Mississippi Kite nesting attempts in Lubbock, Texas, USA, between 2004 and 2015, from which we modeled daily survival rate as a function of local weather conditions, drought severity, and the state of the El Niño Southern Oscillation. We observed significant annual variation in median incubation initiation date (range = May 20 to June 5), the probability of nest success (range = 0.31–0.90), and productivity (range = 0.25–1.00 fledglings per nest). Our models of daily survival rate suggested that higher daily temperatures, severe storm events, extreme drought conditions, and La Niña events negatively influenced nest survival. These results suggest that increasing storm frequency and higher temperatures associated with climate change are likely to decrease the nesting success of Mississippi Kites in the southern Great Plains.

Duckling survival is an important influence on recruitment in several North American Anas species. White-cheeked Pintail (Anas bahamensis) breeding in Puerto Rico encounter a variety of wetland types that may influence duckling survival. We monitored fates of 92 radio-tagged ducklings in 31 broods in 5 wetland habitat types at Humacao Nature Reserve in southeastern Puerto Rico from 2000 to 2002. Wetlands included 2 separate coastal lagoon complexes, mangrove forest, and managed and unmanaged wetland impoundments containing herbaceous vegetation. We used known-fate models to estimate daily and interval survival rates of ducklings and broods. We conducted conservative and liberal analyses of survival because of uncertain fates of 36 ducklings. In the conservative analysis, the most parsimonious model for duckling survival contained wetland type and a positive influence of daily precipitation. In the liberal analysis, duckling survival also varied among wetlands, was positively influenced by daily precipitation, but negatively influenced by hatch date. Brood survival was also positively influenced by precipitation and female body mass. Managed wetland impoundments and shallowly flooded lagoon habitats containing ferns, interspersed cattail (Typha dominguensis), and other herbaceous cover promoted up to 3 times higher survival of ducklings over the course of a 30-day duckling period than we found in mangroves, more deeply flooded lagoons with predominately restricted shoreline cover, or unmanaged impoundments overgrown with vegetation. Broad confidence intervals for survival estimates among wetlands preclude unequivocal interpretation, but our results suggest that White-cheeked Pintail ducklings survive poorly in mangroves but benefit from appropriate management.

Effective communication with other scientists is an essential component of the scientific process, underlying success in publishing papers, building collaborations, securing grants and jobs, and stimulating further research. Oral presentations at professional meetings provide an opportunity to share research findings with a relatively broad scientific audience. However, many scientists give talks that are crowded with methods and data, accompanied by poor visuals, and, most unfortunately, lacking in narrative arc. Here, I provide strategies for distilling research findings into a short-format talk, capturing the audience's attention, and delivering a compelling and visually engaging story. I argue that the material should be designed to interest a wide range of meeting attendees, not just experts in a narrow field. I also advocate principles of good storytelling, with the aim of leading the audience through a compelling journey of discovery that concludes with a memorable takeaway message.

Habitats around the Gulf of Mexico (GOM) provide critical resources for Nearctic–Neotropical migratory landbirds, the majority of which travel across or around the GOM every spring and fall as they migrate between temperate breeding grounds in North America and tropical wintering grounds in the Caribbean and Central and South America. At the same time, ecosystems in the GOM are changing rapidly, with unknown consequences for migratory landbird populations, many of which are experiencing population declines. In general, the extent to which events encountered en route limit migratory bird populations is not well understood. At the same time, information from weather surveillance radar, stable isotopes, tracking, eBird, and genetic datasets is increasingly available to address many of the unanswered questions about bird populations that migrate through stopover and airspace habitats in the GOM. We review the state of the science and identify key research needs to understand the impacts of en route events around the GOM region on populations of intercontinental landbird migrants that breed in North America, including: (1) distribution, timing, and habitat associations; (2) habitat characteristics and quality; (3) migratory connectivity; and (4) threats to and current conservation status of airspace and stopover habitats. Finally, we also call for the development of unified and comprehensive long-term monitoring guidelines and international partnerships to advance our understanding of the role of habitats around the GOM in supporting migratory landbird populations moving between temperate breeding grounds and wintering grounds in Mexico, Central and South America, and the Caribbean.