The publication of a U.S. estimate of bird–window collisions by Loss et al. is an example of the somewhat contentious approach of using extrapolations to obtain large-scale estimates from small-scale studies. We review the approach by Loss et al. and other authors who have published papers on human-induced avian mortality and describe the drawbacks and advantages to publishing what could be considered imperfect science. The main drawback is the inherent and somewhat unquantifiable bias of using small-scale studies to scale up to a national estimate. The direct benefits include development of new methodologies for creating the estimates, an explicit treatment of known biases with acknowledged uncertainty in the final estimate, and the novel results. Other overarching benefits are that these types of papers are catalysts for improving all aspects of the science of estimates and for policies that must respond to the new information.

Building collisions, and particularly collisions with windows, are a major anthropogenic threat to birds, with rough estimates of between 100 million and 1 billion birds killed annually in the United States. However, no current U.S. estimates are based on systematic analysis of multiple data sources. We reviewed the published literature and acquired unpublished datasets to systematically quantify bird–building collision mortality and species-specific vulnerability. Based on 23 studies, we estimate that between 365 and 988 million birds (median = 599 million) are killed annually by building collisions in the U.S., with roughly 56% of mortality at low-rises, 44% at residences, and <1% at high-rises. Based on >92,000 fatality records, and after controlling for population abundance and range overlap with study sites, we identified several species that are disproportionately vulnerable to collisions at all building types. In addition, several species listed as national Birds of Conservation Concern due to their declining populations were identified to be highly vulnerable to building collisions, including Golden-winged Warbler (Vermivora chrysoptera), Painted Bunting (Passerina ciris), Canada Warbler (Cardellina canadensis), Wood Thrush (Hylocichla mustelina), Kentucky Warbler (Geothlypis formosa), and Worm-eating Warbler (Helmitheros vermivorum). The identification of these five migratory species with geographic ranges limited to eastern and central North America reflects seasonal and regional biases in the currently available building-collision data. Most sampling has occurred during migration and in the eastern U.S. Further research across seasons and in underrepresented regions is needed to reduce this bias. Nonetheless, we provide quantitative evidence to support the conclusion that building collisions are second only to feral and free-ranging pet cats, which are estimated to kill roughly four times as many birds each year, as the largest source of direct human-caused mortality for U.S. birds.

The Kittlitz's Murrelet (Brachyramphus brevirostris) has been proposed for listing under the U.S. Endangered Species Act, and is classified as critically endangered by the International Union for the Conservation of Nature (IUCN). A significant portion of the global population occurs in Glacier Bay, Alaska, where steep population declines have been previously reported. To further examine Kittlitz's Murrelet population trends we replicated a 1993 survey in 2009 and 2010 using the same lead observer, the same transect lines, and similar methods. We found the number of Kittlitz's Murrelets unchanged since 1993. Other seabird surveys were conducted in Glacier Bay between 1991 and 2008 by federal agencies, using a variety of sampling designs. We added our surveys to previously published surveys, correcting for percentage of murrelets identified to species to enable comparison. When all surveys were analyzed collectively, the Kittlitz's Murrelet population showed no significant trend between 1991 and 2010 (P = 0.51). A power analysis showed high power (>0.99) to detect a decline had the population truly been declining at a rate of −11% per year, allowing us to reject the prior published conclusion of decline rates of −10.7% to −14.4% per year in Glacier Bay. The prior result of murrelet population decline was driven by a high population estimate from an isolated, nonstandard survey in 1991. Our three surveys in 1993, 2009, and 2010 provide a direct long-term comparison of standardized surveys, and show a more comprehensive picture of the Kittlitz's Murrelet population trend in Glacier Bay. We suggest the previous conclusion of a declining trend was influenced by anchoring bias, which attached undue certainty to the initial observation. The revised population trend in Glacier Bay indicates Kittlitz's Murrelets are not at imminent risk of extinction.

Common Raven (Corvus corax) numbers and distribution are increasing throughout the sagebrush steppe, influencing avian communities in complex ways. Anthropogenic structures are thought to increase raven populations by providing food and nesting subsidies, which is cause for concern because ravens are important nest predators of sensitive species, including Greater Sage-Grouse (Centrocercus urophasianus). During 2007–2009, we located raven nests in southeastern Idaho and conducted a resource selection analysis. We measured variables at multiple spatial scales for 72 unique nest locations, including landscape-level vegetation characteristics and anthropogenic structures. Using generalized linear mixed models and an information-theoretic approach, we found a 31% decrease in the odds of nesting by ravens for every 1 km increase in distance away from a transmission line. Furthermore, a 100-m increase in distance away from the edge of two different land cover types decreased the odds of nesting by 20%, and an increase in the amount of edge by 1 km within an area of 102.1 ha centered on the nest increased the odds of nesting by 49%. A post hoc analysis revealed that ravens were most likely to nest near edges of adjoining big sagebrush (Artemisia tridentata) and land cover types that were associated with direct human disturbance or fire. These findings contribute to our understanding of raven expansion into rural environments and could be used to make better-informed conservation decisions, especially in the face of increasing renewable energy development.

Effective conservation of migratory species requires comprehensive knowledge of annual movement patterns. Such information is sparse for the Long-billed Curlew (Numenius americanus), a North American endemic shorebird of conservation concern. To test hypotheses about individual and area differences in migratory patterns across western North America, we tagged 29 curlews with satellite transmitters at breeding sites in Oregon, Nevada, and Montana. Transmissions from 28 birds for up to 4 years demonstrated that all wintered within the species' known winter range, including 9 from Oregon tracked to agricultural areas of California's Central Valley; 5 from Nevada tracked to the Central Valley, northern Gulf of California, or west coast of Baja California, Mexico; and 14 from Montana that wintered inland, from the Texas Panhandle south to the Mexican Plateau, or near the Gulf of Mexico. Montana breeders migrated east of the Rocky Mountains and traveled more than twice the distance of Oregon and Nevada breeders. Montana birds also stopped more often and longer during most passages. As a group, curlews arrived on their Oregon breeding grounds earlier than in Montana, while males preceded females in Montana and possibly Oregon. No consistent pattern emerged between sexes in departure from breeding areas, although within pairs males departed later than their mates. Individuals exhibited strong fidelity to breeding and wintering sites, and many birds showed a strong propensity for agricultural regions during winter. Our results underscore the importance of studying migration behavior across the breeding range to adequately capture variation in migratory patterns of a species.

Cannibalism occurs regularly across a broad range of taxa with a variety of ecological and evolutionary consequences. Rises in sea surface temperature (SST) have been linked to increased cannibalism in some species, including polar bears (Ursus maritimus), Peruvian anchovy (Engraulis ringens), and Peruvian hake (Merluccius gayi peruanus), and might be expected in birds that depend on marine food webs for sustenance. Increased SSTs are associated with lowered ocean thermoclines and weakened upwellings. These changes, in turn, lead to decreased productivity in surface water and movement of surviving forage fish to deeper water, thereby food-stressing surface feeders such as gulls, diminishing energy intake and lengthening foraging bouts. While controlling for a suite of other environmental factors, we tested whether egg cannibalism and hatching success were independent of rises in local SST at a colony of Glaucous-winged Gulls (Larus glaucescens) and Glaucous-winged × Western Gull (L. glaucescens × occidentalis) hybrids during 2006–2011 on Protection Island, Washington, USA. Cannibalism increased and hatching success decreased with rises in SST. It is unclear if rises in SST impact overall population trends. Gulls are multiyear breeders; if they experience reproductive failure during one or several El Niño-Southern Oscillation–related events, they typically have other opportunities to breed. With rising SSTs associated with climate change, however, increasing levels of cannibalism could lead to declining populations in the absence of compensatory adaptive modifications or range shifts.

Birds are expected to select nest sites that maximize their reproductive success. In some settings, particularly in human-modified landscapes, birds may make maladaptive choices based on unreliable cues. We studied nest-site selection and the factors that influence reproductive success of Common Yellowthroats (Geothlypis trichas) in managed switchgrass (Panicum virgatum) grasslands in Iowa. We compared vegetation variables at 115 nest sites and corresponding random points. Conditional logistic regression was used to relate nest success, brood parasitism, and number of young fledged per successful nest to vegetation characteristics. Common Yellowthroats selected nest sites with denser and more senescent vegetation, and more forb cover compared with random points. Nest success, however, was negatively related to forb cover. Brood parasitism was not well-explained by any variables. Number of young fledged was positively related to the proportion of senescent vegetation. Selection of nest sites with denser vegetation and more senescent vegetation is consistent with variables reported in the literature and emphasizes the importance of nonharvested areas for Common Yellowthroats in switchgrass fields. Maladaptive preference for nest sites with more forbs could have negative consequences for Common Yellowthroat populations if the pattern we saw persists or applies to other settings.

Two hundred years of Neotropical ornithology have resulted in comprehensive monographic guides and thousands of scientific papers. Nonetheless, information is not evenly distributed across the region. Replicating previous assessments of Neotropical ornithology, we performed searches at Zoological Record of publications on birds of Neotropical countries (1996–2011) using number of publications as an indication of current knowledge. We calculated the ratio of papers per species richness for each country and compared number of publications in different subjects during the 1979–1995 and 1996–2011 periods. Further, we quantified publications in two Neotropical journals: Cotinga and Ornitología Neotropical. As in previous assessments, Mexico, Argentina, and Brazil were the best-represented countries, accounting for 54% of all references. Most Central American and Caribbean countries, as well as Guianan states, Paraguay, and Uruguay, remain poorly represented. All top-12 better-documented countries experienced significant increases in publication numbers. However, only the four better-documented countries have a ratio per species higher than 1.00. Numbers of papers published in Cotinga were led by Brazil and Ecuador, whereas Brazil and Argentina are the better-represented countries in Ornitología Neotropical. Poorly documented countries in these journals from the entire Neotropics are similar to those in Zoological Record. Neotropical residents authored 74% of papers published in Ornitología Neotropical. Ornithologists are currently contributing an unprecedented wealth of data on systematics and taxonomy, biogeography, evolution, natural history, and conservation of Neotropical birds. Current, unprecedented technological advancements (Internet, powerful bioinformatics, open-source algorithms, DNA sequencing) provide promising perspectives for the further development of Neotropical ornithology.

Freed and Cann (2013) criticized our use of linear models to assess trends in the status of Hawaiian forest birds through time (Camp et al. 2009a, 2009b, 2010) by questioning our sampling scheme, whether we met model assumptions, and whether we ignored short-term changes in the population time series. In the present paper, we address these concerns and reiterate that our results do not support the position of Freed and Cann (2013) that the forest birds in the Hakalau Forest National Wildlife Refuge (NWR) are declining, or that the federally listed endangered birds are showing signs of imminent collapse. On the contrary, our data indicate that the 21-year long-term trends for native birds in Hakalau Forest NWR are stable to increasing, especially in areas that have received active management.

Several studies have emphasized the importance of postfledging survival when estimating avian population growth rates, yet high variation exists in reported estimates. Mechanisms influencing postfledging survival also remain poorly understood. The influences of local habitat quality and landscape context on postfledging movements also remain largely undocumented. We measured daily postfledging survival and movements in Ovenbirds (Seiurus aurocapilla) in selection cut plots (30–40% basal area removal) and controls. Specifically, we tested predictions from the “concealment” hypothesis (higher survival/shorter movements with increased fledgling concealment), “body condition” hypothesis (higher survival/longer movements with increased body mass), and “predator abundance” hypothesis (higher survival/shorter movements when predator abundance is low) by monitoring fledgling survival (n = 55) and movements (n = 41) during the first 2 weeks postfledging. Fledglings were monitored over 2 breeding seasons in 5 pairs of experimental plots, 25 ha each (1 control and 1 treated plot per pair), located in mature hardwood stands. We found support for an effect of predator abundance on survival (i.e. effects of plot-level abundance of red squirrels and year). Models including habitat variables or body mass received weak support. A positive trend for effect of body mass on movement between successive locations was found but no evidence for an effect of predator abundance or habitat variables. These findings indicate that spatiotemporal variation in predator abundance was a key factor determining daily postfledging survival rate in this Ovenbird population; however, predator abundance did not influence movement rate, suggesting that fledgling Ovenbirds were unable to respond to predation risk.

Estuarine intertidal habitats are heterogeneous, therefore migratory shorebirds are expected to forage in microhabitats where they can maximize their energy intake. Identifying proximate factors that migratory shorebirds use to accept or reject a particular habitat patch will help land managers make conservation and restoration decisions that provide the greatest benefits to shorebird populations during migration, a period of intense energy usage. We examined whether small semipermanent tidal channels were preferentially used by foraging Western Sandpipers (Calidris mauri) and Dunlins (C. alpina) during a spring migratory stopover in Bandon Marsh, an Oregon, USA, estuary. Further, we tested alternative hypotheses about how channels might be beneficial to shorebirds by examining infauna abundance, composition, and depth alongside channels compared with that in open mudflats. The densities of Western Sandpipers and Dunlins were at least 4 times higher along channels than in open mudflat habitats. Infauna along channels were twice as abundant as those in the surrounding mudflats, and infauna were generally found closer to the surface. Furthermore, sediment alongside channels required less than half the force to probe, probably increasing shorebirds' overall access to prey. We conclude that shorebirds selected microhabitats near channels because of the greater food abundance and availability. Additional evidence suggested that another microhabitat, patches of red algae (Gracilaria sp.), may also have conferred advantages on foraging shorebirds. Channels may be a valuable microhabitat to consider when selecting conservation areas for shorebirds, and maintaining channels (e.g., through maintaining natural hydrology and sedimentation patterns) should be considered in management practices.

The Rusty Blackbird (Euphagus carolinus), an uncommon songbird often associated with northern coniferous wetlands, has experienced a precipitous population decline since at least the early 20th century. Here, we provide the first analysis of breeding-habitat occupancy at the wetland scale and make recommendations for streamlined monitoring. We modeled occupancy and detectability as a function of site (i.e. habitat-based) and sampling (i.e. visit-specific) variables collected at 546 wetlands in northern New England, USA. Wetland occupancy (mean ± SE = 0.07 ± 0.02 in randomly selected wetlands, and 0.12 ± 0.02 in all wetlands surveyed) was best explained by variables describing Rusty Blackbird foraging habitat (PUDDLES: a proxy for shallow water), nesting habitat (coniferous adjacent uplands), and evidence of beavers. In contrast to Rusty Blackbirds' selection of pole-stage conifers at the nest-site scale, stand age did not affect occupancy at the wetland scale. It appears that most wetlands in northern coniferous forest landscapes, regardless of stand age, offer dense conifer patches nearby and provide suitable breeding habitat if quality foraging sites (e.g., areas of shallow water) also are available. Detectability (0.29 ± 0.04) decreased with increasing wind speed, and decreased about fourfold over the course of the breeding season. Rusty Blackbirds responded to broadcast of conspecific vocalizations by flying toward the observer and perching more often than prior to broadcast, demonstrating that broadcasts can be a useful tool to enhance visual detectability. Given our results, observers can now focus site selection on wetlands and sampling conditions most likely to maximize detections of Rusty Blackbirds.

Continuing human population growth and urbanization in Florida may impact the survival of native birds, including the Florida Mottled Duck (Anas fulvigula fulvigula). Survival of adult females is an important vital rate that affects population growth rates, thus estimates of female survival as well as sources of variation affecting survival rates are needed for the development of a more informed conservation plan for Florida Mottled Ducks. In this study, we estimated annual and seasonal survival rates of radio-tagged adult female Mottled Ducks (n = 236) using urban and rural areas in southern Florida from 2008 to 2011. Additionally, we tested for differences in survival among ducks using different geographic areas during the breeding season and that were exposed to different hunting regimes during the hunting season. Identifying the geographic areas where higher rates of mortality occur may allow for more effective habitat and harvest management of the Florida subspecies of Mottled Duck. Annual survival was higher for ducks that used urban areas (74%) than for ducks that did not (47%). Daily survival rates were lowest during the breeding season. Females that used Everglades-type habitat during the breeding season had higher seasonal survival rates (78–85%) than those that did not (37–47%). We found evidence of density-dependent mortality during and after the hunting season. Differences in hunting season survival for ducks that used unhunted rural areas (88%) when compared with survival of ducks that used areas with open (87%) or quota hunting systems (85%) were not significant. Differences in survival among study years were negligible. Our results indicate that Florida Mottled Ducks survive at high rates in urbanized areas, but may benefit from increases in the quantity and quality of breeding habitats.