Showing papers in "Journal of Field Ornithology in 2016"

Post-fledging survival of altricial birds: ecological determinants and adaptation

Abstract: For altricial young, fledging is an abrupt step into an unknown environment. Despite increasing numbers of studies addressing the post-fledging period, our current knowledge of the causes and consequences of post-fledging survival remains fragmentary. Here, we review the literature on post-fledging survival of juvenile altricial birds, addressing the following main questions: Is low post-fledging survival a bottleneck in the altricial reproductive cycle? What is known of proximate and ultimate causal factors such as trophic relations (food and predation), habitat conditions, or abiotic factors acting in the post-fledging period? We analyzed weekly survival estimates from 123 data series based on studies of 65 species, covering weeks 1–13 post-fledging. As a general pattern, survival of fledglings was low during the first week post-fledging (median rate = 0.83), and improved rapidly with time post-fledging (week 4 median rate = 0.96). For ground-nesting species, survival immediately after leaving nests was similar to egg-to-fledging survival. For species breeding above-ground, survival during the first week post-fledging was substantially lower than during both the nestling period and later post-fledging stages. Thus, the early post-fledging period is a bottleneck of markedly elevated mortality for most altricial species. Predation was the main proximate cause of mortality. Various factors such as habitat, annual and seasonal variation in the environment, and the physical condition of fledglings have been found to affect post-fledging survival. Individual survival depended strongly on physical traits such as mass and wing length, which likely influence the ability of fledglings to escape predation. Trophic relationships at various levels are the main ultimate driver of adaptation of traits relevant to survival during the pre- and post-fledging periods. Spatiotemporal dynamics of food resources determine the physical development of juveniles and, in turn, their performance after fledging. However, predators can cause quick and efficient selection for fledgling traits and adult breeding decisions. Parental strategies related to clutch size and timing of breeding, and the age and developmental stage at which young fledge have substantial effects on post-fledging survival. The intensity and duration of post-fledging parental investment also influences fledgling survival. Post-fledging mortality is therefore not a random and inevitable loss. Traits and strategies related to fledging and the post-fledging stage create large fitness differentials and, therefore, are integral, yet poorly understood, parts of the altricial reproductive strategy.

Computer‐automated bird detection and counts in high‐resolution aerial images: a review

Abstract: Bird surveys conducted using aerial images can be more accurate than those using airborne observers, but can also be more time-consuming if images must be analyzed manually. Recent advances in digital cameras and image-analysis software offer unprecedented potential for computer-automated bird detection and counts in high-resolution aerial images. We review the literature on this subject and provide an overview of the main image-analysis techniques. Birds that contrast sharply with image backgrounds (e.g., bright birds on dark ground) are generally the most amenable to automated detection, in some cases requiring only basic image-analysis software. However, the sophisticated analysis capabilities of modern object-based image analysis software provide ways to detect birds in more challenging situations based on a variety of attributes including color, size, shape, texture, and spatial context. Some techniques developed to detect mammals may also be applicable to birds, although the prevalent use of aerial thermal-infrared images for detecting large mammals is of limited applicability to birds because of the low pixel resolution of thermal cameras and the smaller size of birds. However, the increasingly high resolution of true-color cameras and availability of small unmanned aircraft systems (drones) that can fly at very low altitude now make it feasible to detect even small shorebirds in aerial images. Continued advances in camera and drone technology, in combination with increasingly sophisticated image analysis software, now make it possible for investigators involved in monitoring bird populations to save time and resources by increasing their use of automated bird detection and counts in aerial images. We recommend close collaboration between wildlife-monitoring practitioners and experts in the fields of remote sensing and computer science to help generate relevant, accessible, and readily applicable computer-automated aerial photographic census techniques.

A classification scheme for avian diet types

Abstract: Descriptions of avian diets currently lack consistent terminology and standardized methods. As a consequence, most available classifications, especially for tropical birds, are inconsistent and often misleading. We identified 23 food categories most commonly eaten by birds (e.g., seeds, fruits, and insects) and proposed standard names that accurately describe the diet type associated with each food category (e.g., granivore, frugivore, and insectivore). We also propose a classification scheme for avian diet types that takes into account the number of food categories consumed and the volumetric proportion (based on stomach content analysis) of each category eaten to indicate the diet type of a species, using a binomial terminology. Given that bird diets encompass a continuum between some extremes commonly treated as distinct categories, we adopted arbitrary breaking points to delimit distinct diet types. For example, species with different proportions of insects and fruits in their diets can be classified as insectivores (IN), insectivores secondarily frugivores (INFR), frugivores-insectivores (FR-IN), frugivore secondarily insectivores (FRIN), and frugivores (FR). Because many factors can influence avian diets, the diet types of species can also be classified based on age-related, sexual, seasonal, and/or geographic variation, e.g., young are insectivores and adults are frugivores, we believe that our classification scheme provides a standardized terminology that can contribute to a more consistent and effective exchange of information about avian diets.

Dietary opportunism, resource partitioning, and consumption of coffee berry borers by five species of migratory wood warblers (Parulidae) wintering in Jamaican shade coffee plantations

Abstract: Diets reflect important ecological interactions, but are challenging to quantify for foliage-gleaning birds. We used regurgitated stomach samples from five primarily insectivorous species of long-distance migrant warblers (Parulidae) wintering in two moderate-elevation shade coffee farms in Jamaica to assess both foraging opportunism and prey resource partitioning. Our results, based primarily on 6120 prey items in 80 stomach samples collected during a one-week period in March 2000, confirm opportunism. The diets of all five warblers, including American Redstarts (Setophaga ruticilla), Black-and-White Warblers (Mniotilta varia), Black-throated Blue Warblers (S. caerulescens), Northern Parulas (S. americana), and Prairie Warblers (S. discolor), overlapped strongly based on consumption of the same prey types, even many of the same prey species (4 of 10 interspecific overlaps >0.9, range = 0.74–0.97). Moreover, all five species fed on similarly small, often patchily distributed prey, including coffee berry borers (Hypothenemus hampei; Coleoptera, Curculionidae). Nonetheless, permutational multivariate analysis of variance also revealed that the diets of these species differed significantly, primarily with respect to prey mobility (winged vs. sessile); American Redstarts fed on the most mobile prey, and Northern Parulas on the least mobile prey and a relatively restricted set of prey taxa compared to the other four species of warblers. Overall, our results suggest both dietary opportunism consistent with a migratory life-history, and interspecific resource partitioning consistent with differences in morphology and foraging behavior during a food-limited season. Having provided evidence of the three necessary conditions, namely intraspecific competition, resource limitation, and interspecific overlap in resource use, the results of our study, in combination with those of other studies, also provide evidence of interspecific competition among wintering migrant insectivores. We thus argue that diffuse interspecific exploitative food competition may be more important than previously recognized.

Dichotomous strategies? The migration of Whimbrels breeding in the eastern Canadian sub‐Arctic

Abstract: The conservation of migratory birds requires internationally coordinated efforts that, in turn, demand an understanding of population dynamics and connectivity throughout a species' range Whimbrels (Numenius phaeopus) are a widespread long-distance migratory shorebird with two disparate North American breeding populations Monitoring efforts suggest that at least one of these populations is declining, but the level of migratory connectivity linking the two populations to specific non-breeding sites or identifiable conservation threats remains unclear We deployed light-level geolocators in 2012 to track the migration of Whimbrels breeding near Churchill, Manitoba, Canada In 2013, we recovered 11 of these geolocators, yielding complete migration tracks for nine individuals During southbound migration, six of the nine Whimbrels stopped at two staging sites on the mid-Atlantic seaboard of the United States for an average of 22 days, whereas three individuals made nonstop flights of ~8000 km from Churchill to South America All individuals subsequently spent the entire non-breeding season along the northern coasts of Brazil and Suriname On their way north, all birds stopped at the same two staging sites used during southbound migration Individuals staged at these sites for an average of 34 days, significantly longer than during southbound migration, and all departed within a 5-day period to undertake nonstop flights ranging from 2600 to 3100 km to the breeding grounds These extended spring stopovers suggest that female Whimbrels likely employ a mixed breeding strategy, drawing on both endogenous and exogenous reserves to produce their eggs Our results also demonstrate that this breeding population exhibits a high degree of connectivity among breeding, staging, and wintering sites As with other long-distance migratory shorebirds, conservation efforts for this population of Whimbrels must therefore focus on a small, but widely spaced, suite of sites that support a large proportion of the population

Evidence for longitudinal migration by a “sedentary” Brazilian flycatcher, the Ash-throated Casiornis

Abstract: The digitalization of museum collections and concurrent increase in citizen-scienceinitiatives is ushering in an era of unprecedented availability of primary biodiversity data. These changespermit a reappraisal of phenological patterns of tropical species. I examined spatio-temporal variation in thedistribution patterns of an ostensibly sedentary endemic Brazilian flycatcher, the Ash-throated Casiornis(Casiornis fuscus), using both specimen data from museums and sighting records and rich media data fromcitizen-science initiatives. I found compelling evidence for partial intratropical longitudinal migration toAmazonia and the Cerrado biomes from the species’ core range in the semi-desert Caatinga biome andadjacent ecotones. These records from outside of the Caatinga were distributed during the height of the dryseason from April to October, although the Caatinga is not entirely vacated at this time. This pattern ofpartial migration leads to a doubling of the distributional range of Ash-throated Casiornises and stronglysuggests that the species is a breeding near-endemic of the Caatinga biome. This pattern was potentiallypreviously not apparent because of significant biases in specimen collection between biomes, giving a falsesense of abundance in the Brazilian Amazon.

GPS‐tracking reveals non‐breeding locations and apparent molt migration of a Black‐headed Grosbeak

Abstract: Black-headed Grosbeaks (Pheucticus melanocephalus) have been observed to undergo prebasic molt during fall in the North American Monsoon region of the southwestern United States and northwestern Mexico, but it is unknown whether molt migration is pervasive across populations of the species. During the 2014 breeding season, we GPS-tagged (where GPS is global positioning system) nine adult Black-headed Grosbeaks in Yosemite National Park with archival GPS tags to determine specific locations where grosbeaks breeding in Yosemite spent portions of the non-breeding season, and to assess whether those locations were consistent with molt migration. On 2 June 2015, one of these birds, a male GPS-tagged on 19 June 2014, was recaptured with its GPS unit still attached. Data downloaded from the unit revealed that, by 20 August 2014, the bird had moved 1300 km from Yosemite National Park to Sonora, Mexico, where it remained until at least 15 October 2014. By 24 November 2014, the grosbeak had moved >1300 m from Sonora to the Michoacan-Jalisco border region, where it remained until the last GPS-determined location was obtained on 24 March 2015. The seasonal timing of these movements and the length of stay in Sonora are consistent with the expected behavior of a molt-migrating bird. Remote-sensed enhanced vegetation index (EVI) data indicated that the grosbeak arrived in the monsoon region near the area's annual peak in EVI, and then, as the index was declining sharply, departed for the Michoacan-Jalisco region, where the index also declined during the same period, but substantially less so than in Sonora. Climate change in the coming decades is expected to delay the annual onset of the monsoon while also accelerating the initiation of arid, summer-like conditions throughout much of western North America, possibly yielding a temporal mismatch between fall migration and the monsoon-driven conditions that may be critical for molt-migrating birds.

A novel nest‐monitoring camera system using a Raspberry Pi micro‐computer

Abstract: The utility, availability, cost-effectiveness, and reliability of prefabricated video systems designed to monitor wildlife have lagged behind the unique and varied needs of many researchers. Many systems are limited by inflexible video settings, lack of adequate data storage, and cannot be programmed by the user. More sophisticated systems can be cost prohibitive, and the literature describing remote wildlife video monitoring has, for the most part, not incorporated advances in camera and computer technology. Here, we present details of a pilot study to design and construct a lower cost (US $340) nest camera system to record the behavior of Acorn Woodpeckers (Melanerpes formicivorus) in artificial tree cavity nests. This system incorporates a Raspberry Pi micro-computer, Pi NoIR infrared camera, a wireless adapter to transmit video over the Internet, and Deka rechargeable gel batteries for power. We programmed the system to motion-sense, to record exclusively during daylight hours, and to automatically upload videos to the cloud over wireless Internet. The Raspberry Pi micro-computer does not require advanced programming or electrical engineering skills to build and configure and, because it is programmable, provides unprecedented flexibility for field researchers who wish to configure the system to the specific needs of their study. RESUMEN. Un sistema de monitoreo de nidos novedoso usando micro computadoras Raspberry Pi La utilidad, disponibilidad, la relaci on eficiencia costo y la confiabilidad de sistemas de video prefabricados dise~ nados para el monitoreo de vida salvaje han estado atrasado de las necesidades unicas y variadas de muchos investigadores. Muchos sistemas est an limitados por los ajustes de video inflexibles que no tienen la capacidad adecuada para guardar datos y no pueden ser programados por el usuario. Sistemas m as sofisticados pueden ser prohibitivos por su costo y la literatura describiendo monitoreo de vida salvaje con videos, ha estado mayormente, desacoplada de los avances tecnol ogicos en c amaras y computadores. Aqu ı presentamos los detalles de un estudio piloto para dise~ nar y construir una c amara para nidos de bajo costo (US $340) para grabar el comportamiento de Melanerpes formicivorus en nidos en cavidades artificiales. Este sistema incorpora microcomputadoras Raspberry Pi, c amara infrarrojo Pi NoIR, un adaptador inal ambrico para transmitir video a trav es de internet y bater ıas recargables Deka de gel. Programamos el sistema con sensores de movimiento para grabar exclusivamente durante horas del d ıa y para que autom aticamente subiera los videos a la nube a trav es de internet inal ambrico. La micro computadora Raspberry Pi no requiere de programaci on avanzada o habilidades en ingenier ıa el ectrica para su construcci on y configuraci on. Debido a que es programable provee flexibilidad sin precedentes para investigadores en el campo que desean configurar el sistema para las necesidades espec ıficas de su estudio.

Breeding sites and winter site fidelity of Piping Plovers wintering in The Bahamas, a previously unknown major wintering area

Abstract: Most of the known wintering areas of Piping Plovers (Charadrius melodus) are along the Atlantic and Gulf coasts of the United States and into Mexico, and in the Caribbean. However, 1066 threatened/endangered Piping Plovers were recently found wintering in The Bahamas, an area not previously known to be important for the species. Although representing about 27% of the birds counted during the 2011 International Piping Plover Winter Census, the location of their breeding site(s) was unknown. Thus, our objectives were to determine the location(s) of their breeding site(s) using molecular markers and by tracking banded individuals, identify spring and fall staging sites, and examine site fidelity and survival. We captured and color-banded 57 birds in January and February 2010 in The Bahamas. Blood samples were also collected for genetic evaluation of the likely subspecies wintering in The Bahamas. Band re-sightings and DNA analysis revealed that at least 95% of the Piping Plovers wintering in The Bahamas originated on the Atlantic coast of the United States and Canada. Re-sightings of birds banded in The Bahamas spanned the breeding distribution of the species along the Atlantic coast from Newfoundland to North Carolina. Site fidelity to breeding and wintering sites was high (88–100%). Spring and fall staging sites were located along the Atlantic coast of the United States, with marked birds concentrating in the Carolinas. Our estimate of true survival for the marked birds was 0.71 (95% CI: 0.61–0.80). Our results indicate that more than one third of the Piping Plover population that breeds along the Atlantic coast winters in The Bahamas. By determining the importance of The Bahamas to the Atlantic subspecies of Piping Plovers, future conservation efforts for these populations can be better focused on where they are most needed.

New insights from an attempt to reintroduce Red‐cockaded Woodpeckers in northern Florida

Abstract: Red-cockaded Woodpeckers (Leuconotopicus borealis) were extirpated from Tall Timbers Research Station in the early 1980s. To help meet conservation goals established for this imperiled species in north Florida, we attempted to reintroduce the woodpecker to the research station by constructing artificial cavities and translocating 27 subadult woodpeckers from 2006 to 2010. Successful nesting occurred during the breeding season following the initial translocation of four male–female pairs. Translocations were suspended in 2011 when breeding groups occupied 6 of 12 available clusters of cavity trees. The population increased steadily after 2011 and, in 2015, totaled 28 adults distributed among nine breeding groups plus a single territorial male. The 2015 population included 22 individuals produced at Tall Timbers, an immigrant female, and five birds originally translocated as subadults. Seven breeding groups in 2015 also had non-breeding helpers. New milestones documented during this reintroduction attempt included recruitment of locally produced birds into the breeding population, excavation of natural cavities, two immigration events, and natural expansion into an unoccupied area. We also documented the threat that heavy rains may pose to small populations. Expenses totaled $211,000 during the first 5 yr when translocations and cavity construction were the primary activities. After translocations were suspended, recurring management expenses were ~ $6500 annually. Because our founding population was small (N = 12), intermittent translocations will likely be needed in the future to offset the deleterious effects of inbreeding.

Bird conservation and biodiversity research in Mexico: status and priorities

Abstract: This is the peer reviewed version of the following article: Peterson, A. T. and Navarro-Siguenza, A. G. (2016), Bird conservation and biodiversity research in Mexico: status and priorities. J. Field Ornithol.. doi:10.1111/jofo.12146, which has been published in final form at doi:10.1111/jofo.12146. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

Use of time-lapse photography and digital image analysis to estimate breeding success of a cliff-nesting seabird

Abstract: Development of new methods for obtaining basic demographic data from difficult-to-access breeding colonies and easily disturbed species is an important challenge in studies of seabirds. We describe a method that can generate data concerning annual breeding success of cliff-nesting seabirds or other colonial birds with open nests. Our method requires only a single visit to a colony every second or third year, and is based on the use of automated time-lapse photography. To test our method, we used time-lapse photos to examine the breeding success of Thick-billed Murres (Uria lomvia) in two breeding colonies in Greenland during the years 2011, 2012, and 2014. Based on the analysis of time-lapse photos, we found that hatching success during the 3 yr of our study ranged from 60% to 81%, fledging success from 89% to 95%, and breeding success from 53% to 74% (Table 1). Use of digital image analysis made it possible to differentiate between breeding and non-breeding birds and determine if and when breeding attempts failed or succeeded. The key to making our method a realistic long-term monitoring technique is the use of an automated, formal image analysis to process the thousands of photos from the time-lapse cameras and, more specifically, to reduce a large number of photos to a manageable number. Using our method, we needed 12–22 h per study plot, depending on the number of breeding sites per plot (range = 47–127) and whether it was the first or the second time the plot was analyzed, to obtain our estimates of hatching, fledging, and breeding success. This included time for data preparation, image analyses, visual inspections, and summarizing data in a spreadsheet. We found that our estimates of breeding success were comparable to those obtained by direct observation in the field. An important aspect of using time-lapse technology is to foresee potential reasons why time-lapse cameras might stop taking pictures, for example, equipment failure (camera, timer, or battery) or interference by visitors (e.g., vandalism or theft). As such, thorough testing of time-lapse systems and selecting camera locations less likely to be disturbed are most important. We believe that use of time-lapse photography in combination with digital image analysis to estimate breeding success can be useful for determining the breeding success of other cliff-nesting seabirds and, more generally, other birds that breed in colonies, especially those located in remote areas and where direct observation may disturb birds.

Year-round spatial movements and trophic ecology of Trindade Petrels (Pterodroma arminjoniana)

Abstract: Trindade Petrels (Pterodroma arminjoniana) are vulnerable gadfly petrels that breed on the remote Trindade Island, located ~1100 km off the Brazilian coast. Little is known about their spatial ecology, and their trophic ecology has only been described for the breeding season. We tagged four Trindade Petrels with global location sensing loggers (GLS) from October 2013 to November 2014 and sampled the blood and feathers (innermost primary and the eighth secondary) of 14 individuals to evaluate their year-round spatial and isotopic ecology. We examined individual distributions, habitat use and suitability, activity, and isotopic values during the breeding, migration, and non-breeding periods. Trindade Petrels used areas in the southwest Atlantic Ocean (between 10°N and 50°S in latitude) during the breeding season. They migrated through pelagic waters of the tropical Atlantic to the northwest Atlantic, where they spent the non-breeding season. Trindade Petrels used mostly tropical to subtropical waters in areas of intermediate to high wind speeds and low marine productivity. Individuals spent more time foraging at night than during the day. During the breeding season, birds in northerly areas had higher carbon-13 values, and birds that used more pelagic areas foraged on prey at a higher trophic level (higher nitrogen-15 values) than those in more southern and coastal areas. Isotopic values during the breeding, migration, and non-breeding periods differed, possibly due to differences among individuals in their at-sea distribution throughout the year. We confirmed the non-breeding distribution of Trindade Petrels, which was previously known only from vessel sightings and stranded birds. Our results also suggest a strong temporal segregation in the at-sea distribution and trophic ecology between two groups of individuals, which might indicate the existence of two separate breeding populations.

Comparison of removal‐based methods for estimating abundance of five species of prairie songbirds

Abstract: Estimating species abundance is important for land managers, especially for monitoring conservation efforts. The two main survey methods for estimating avian abundance are point counts and transects. Previous comparisons of these two methods have either been limited to a single species or have not included detection probability. During the 2012 breeding season, we compared and assessed the efficiency (precision for amount of effort) of point count time of detection (PCTD) and dependent double-observer transect (TRMO) methods based on detection probabilities and abundance estimates of five species of songbirds that use a range of habitats in a prairie system in Montana dominated by sagebrush and grassland vegetation. Our focal species included Vesper Sparrows (Pooecetes gramineus), a generalist species found in both shrub and grassland habitat, shrub-obligate Brewer's Sparrows (Spizella breweri), and McCown's Longspurs (Rhynchophanes mccownii), Horned Larks (Eremophila alpestris), and Western Meadowlarks (Sturnella neglecta), three species of grassland obligates that prefer different grass heights. Detection probabilities were significantly higher for TRMO surveys, with less variation for all five species and differences most pronounced for Brewer's Sparrows and Horned Larks. PCTD surveys required less field effort (~8–20 fewer people minutes per plot) than TRMO surveys because the TRMO surveys required two people. However, time spent on TRMO surveys provided between 0.38 and 87 times more precision per people minute than PCTD surveys. Our results suggest that TRMO surveys provide a more efficient (measured as time spent per unit of standard error) field-based technique in sagebrush prairie systems for the species we investigated, resulting in more precise detection and abundance estimates.

A non-lethal biopsy technique for sampling subcutaneous adipose tissue of small and medium-sized birds: Sampling Subcutaneous Adipose Tissue

Abstract: Analysis of fatty acids from adipose tissue can provide important information about the physiological and nutritional condition of birds. However, non-lethal biopsy procedures and their potential negative effects on small and medium-sized birds have not been adequately assessed. We developed a biopsy procedure for collecting small amounts of adipose tissue from the furcular area of small and medium-sized birds (13–62 g) without adverse effects. The biopsy procedure was performed on Dunlins (Calidris alpina), a medium-sized migratory shorebird, and small hybrid songbirds (European Goldfinch [Carduelis carduelis] × Atlantic Canary [Serinus canaria]). The biopsy involved making a skin incision 2–3 mm long on one side of the furcular region to collect 2–16 mg of adipose tissue. All birds were monitored for 2 weeks after biopsies to examine potential effects of the procedure on body mass, visible fat deposition, time for wound healing, hematocrit levels, total white blood cell counts, and heterophil:lymphocyte ratios. Visible scars were apparent for 10 d for hybrids and 6 d for Dunlins, with no evidence of infection or abnormal scar tissue formation. Body mass of songbirds did not differ before and after the biopsy, but Dunlins increased body mass and visible fat deposition after biopsy. The collection of adipose tissue in the furcular region was performed only for birds with fat scores ≥2, and the tissue collected never represented more than 0.07% of a bird's body mass; we recommend both these values to avoid any possible unknown negative effects. Our non-lethal biopsy technique is relatively simple to perform, and we recommend it as an alternative to lethal methods for sampling adipose tissue in studies of wild and captive birds.

Effects of migration distance on life history strategies of Western and Semipalmated sandpipers in Perú

Abstract: Migration distances of shorebird species correlate with life history strategies. To assess age-specific migratory preparation and adult wing-molt strategies, we studied Western Sandpipers (Calidris mauri) and Semipalmated Sandpipers (C. pusilla) with different migration routes at the Paracas National Reserve in Peru, one of the most austral non-breeding areas for these sandpipers, from 2012 to 2015. Western Sandpipers breed near the Bering Sea, ~11,000 km from Paracas. Semipalmated Sandpiper populations at Paracas are a mixture of short-billed birds from western Arctic breeding sites, plus long-billed birds from eastern sites, ~8000 km distant. Adults of both species arrive in October with primary feathers already partially renewed so wing molt starts at sites further north. Semipalmated Sandpipers with longer bills completed wing molt later than shorter billed birds. Adults of both species prepared for migration in February and March. No juvenile Western Sandpipers prepared for migration, confirming the “slow” over-summering life history strategy of more southerly non-breeding populations. Juvenile Semipalmated Sandpipers showed bimodality in strategies. Most showed no migratory preparation, but, during three non-breeding periods, from 27% to 31% fattened, molted, and partially replaced outer primaries during the pre-migratory period. Juveniles with longer culmens were heavier and tended to have more alternate plumage. Juveniles that were partially molting primaries had longer culmens and more alternate plumage. Juvenile Semipalmated Sandpipers from eastern-breeding populations thus have a higher propensity for a fast life history strategy, and western birds a slow one, at this non-breeding site in Peru. Western-breeding Semipalmated Sandpiper populations thus resemble Western Sandpipers, suggesting a common, possibly distance-related, effect on life history strategy.

Toward a scoring system for species delimitation: a response to Remsen

Abstract: BirdLife International, Girton Road, Cambridge CB3 0NA, United Kingdom Lynx Edicions, Montseny 8, E-08193 Bellaterra, Spain The Biodiversity Consultancy, 3E King’s Parade, Cambridge CB2 1SJ, United Kingdom Department of Zoology, Oxford University, Oxford OX1 3PS, United Kingdom Department of Zoology, Cambridge University, Cambridge CB2 3EJ, United Kingdom Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, United Kingdom

Demographic variation in timing and intensity of feather molt in migratory Fork-tailed Flycatchers (Tyrannus s. savana)

Abstract: Understanding the annual cycle of migratory birds is imperative for evaluating the evolution of life-history strategies and developing effective conservation strategies. Yet, we still know little about the annual cycle of migratory birds that breed at south-temperate latitudes of South America. We aged, sexed, and determined the progression and intensity of body, remige, and rectrix molt of migratory Fork-tailed Flycatchers (Tyrannus s. savana) at breeding sites in southern South America and at wintering sites in northern South America. Molt of both body and flight feathers occurred primarily during the winter. In early winter, a similar proportion of young and adult flycatchers molted remiges and rectrices, but remige molt intensity (number of remiges molting) was greater and primary molt progression (mean primary feather molting) more advanced in adults. In late winter, remige molt intensity and primary molt progression did not differ between age groups. We found no difference between males and females either in the proportion of individuals molting in winter or in the intensity or progress of remige molt. Our results suggest that the nominate subspecies of Fork-tailed Flycatcher undergoes one complete, annual molt on the wintering grounds, and represents the first comprehensive evaluation of molt timing of a migratory New World flycatcher that overwinters in the tropics. Given that breeding, molt, and migration represent three key events in the annual cycle of migratory birds, knowledge of the timing of these events is the first step toward understanding the possible tradeoffs migratory birds face throughout the year. © 2016 Association of Field Ornithologists.

Inter-annual site fidelity and breeding origins of Gray-cheeked Thrushes in white sand forests of the Peruvian Amazon

Abstract: White sand terra firme forests are unusual ecosystems scattered across Amazonia, covering just 3% of the basin. These forests differ from surrounding forests in their scleromorphic vegetation, low nutrient content, and propensity to harbor endemics. We report the capture of 62 Gray-cheeked Thrushes (Catharus minimus) during a study of the understory avifauna of Amazonian white sand forests near Iquitos, Peru, conducted from 20 June to 8 December 2010–2012. We captured and banded Gray-cheeked Thrushes in white sand (N = 57) and adjacent weathered clay (N = 5) terra firme forests. Sampling for three consecutive days at 19 different sites each year, the inter-annual site fidelity rate of Gray-cheeked Thrushes was 4.8% (N = 3). One bird banded in 2010 was recaptured in 2012. Of the 62 birds, 19.3% (N = 12) were recaptured on subsequent days. All recaptures were in white sand forests. The 19.3% recapture rate of Gray-cheeked Thrushes from sites re-sampled no more than 2 d in a given year suggests the presence of settled and perhaps territorial birds. Using rectrices from 12 Gray-cheeked Thrushes, stable-hydrogen isotope analyses (δ2H) suggest that the geographic breeding or natal origin of all sampled birds was likely northwestern North America. Our results suggest that Gray-cheeked Thrushes exhibit site fidelity and may concentrate in white sand forests—an uncommon and scattered ecosystem type in western Amazonia. However, annual tracking of individual Gray-cheeked Thrushes is needed to fully assess regional patterns of settlement and movement, and the connectivity between breeding and wintering areas.

Extra‐pair paternity in a population of Chilean Swallows breeding at 54 degrees south

Abstract: Fil: Ferretti, Valentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentina. Cornell University; Estados Unidos

Abundance and habitat relationships of breeding birds in the Sky Islands and adjacent Sierra Madre Occidental of northwest Mexico

Abstract: National Park Service; Desert Southwest Cooperative Ecosystem Studies Unit; U.S. Fish and Wildlife Service; Sky Island Alliance; Veolia Environment Foundation; University of Montana Graduate School

Sex, growth rate, rank order after brood reduction, and hatching date affect first-year survival of long-lived Herring Gulls

Abstract: Among most species of birds, survival from hatching throughout the first year of life is generally lower than subsequent survival rates. Survival of young birds during their first year may depend on a combination of selection, learning, unpredictable resources, and environmental events (i.e., post-fledging factors). However, knowledge about post-fledging development in long-lived species is usually limited due to a lengthy immature stage when individuals are generally unobservable. Therefore, pre-fledging characteristics are often used to predict the survival of young birds. We assessed effects of nestling growth rates, hatching date, hatching asynchrony, brood size and rank order after brood reduction, and sex on first-year survival of 137 fledglings using a mark-resighting analysis. We found that the survival probability (Phi(1yr) = 0.39) of first-year Herring Gulls (Larus argentatus) in our study colony located at the outer port of Zeebrugge (Belgium) was lower than that of older individuals (Phi(>1yr) = 0.75). All 10 models best supported by our data included nestling growth rate, suggesting that variability in first-year survival may be linked primarily to individual variation in growth. First-year survival was negatively correlated with hatching date and rank order after brood reduction. Hence, carry-over effects of breeding season events such as timing of breeding, early development, and social status had an influence on survival of Herring Gulls after fledging. Furthermore, we found sex-biased mortality in first-year Herring Gulls, with females (Phi(1yr) = 0.45) surviving better than males (Phi(1yr) = 0.38). Although adult survival is generally regarded as the key parameter driving population trajectories in long-lived species, juvenile survival has recently been acknowledged as an important source of variability in population growth rates. Thus, increasing our knowledge of factors affecting age-specific survival rates is necessary to improve our understanding of population dynamics and ultimately life-history variation.

Cooperative breeding among Chinese passerines: inference from social behavior, diet, and migratory status

Abstract: Recent estimates suggest that 9% of bird species are cooperative breeders. However, little is known about the breeding behavior of many species, particularly those in the Indomalayan and Neotropical regions. Our objective was to provide an overview of the prevalence of cooperative breeding among Chinese songbirds. Examination of the social behavior, diet, and migratory status of 55 known cooperative-breeding species of songbirds in China revealed that 90.9% live in small groups, 89.1% are residents in at least one or all their subspecies, 81.8% are insectivores, and 14.5% are omnivores. In contrast, 58.2% of the 55 species are resident insectivores that live in small groups, 10.9% are resident omnivores that live in small groups, and 12.7% include subspecies that are resident insectivores. We used these combinations of traits of known cooperative breeders and phylogenetic relationships to infer that an additional 106 species of songbirds in China are probable cooperative breeders and 22 species are possible cooperative breeders. Our analysis suggests that a maximum of 27.2% (183 of 674 species) of Chinese passerines are cooperative breeders, with more occurring in subtropical southern China than in temperate northern China. Cooperative breeding is the main breeding system of species in the families Corvidae, Pycnonotidae, and, especially, Timaliidae (105 of 183 species, 57%). Based on our analyses, cooperative breeding might be more common than previously assumed, particularly among species in the families Timaliidae, Corvidae, and Sturnidae, and species in southern, subtropical China. Because most cooperative-breeding species in our study were either inferred cooperative breeders or possible cooperative breeders, additional study of these species is needed to confirm our results. A better understanding of the prevalence of cooperative breeding in birds will improve our insight into the evolutionary and ecological factors that select for cooperative breeding.

Nesting behavior of male and female Undulated Antshrikes (Frederickena unduliger)

Abstract: Comportamineto de anidamiento del macho y la hembra en el Batara Undulado (Frederickena unduliger) El Batara Undulado (Frederickena unduliger) habita en el sotobosque denso del bosque humedo en tierras bajas, y al igual que otras especies de hormigueros, algunos aspectos de su comportamiento y ecologia son pobremente conocidos, especialmente su biologia reproductiva. Nosotros proveemos la primera informacion detallada acerca de su biologia reproductiva, basados en tres nidos monitoreados entre Agosto a Diciembre durante los anos 2012 y 2013, dentro de la zona de amortiguacion del Parque nacional Manu, Madre de Dios, Peru. Los nidos (N = 3) fueron copas grandes entretejidas entre dos ramas horizontales. Los huevos eran blancos con lineas y manchas color purpura, y el tamano de nidada en los tres nidos fue dos huevos. Tanto la hembra como el macho participaron en la incubacion, calentamiento y alimentacion de los polluelos, pero unicamente la hembra incubo los huevos durante la noche. La tasa de alimentacion y el tiempo destinado al calentamiento de los polluelos no vario entre sexos.

Migration timing and routes, and wintering areas of Flammulated Owls

Abstract: Determining patterns in annual movements of animals is an important component of population ecology, particularly for migratory birds where migration timing and routes, and wintering habitats have key bearing on population dynamics. From 2009 to 2011, we used light-level geolocators to document the migratory movements of Flammulated Owls (Psiloscops flammeolus). Four males departed from breeding areas in Colorado for fall migration between ≤5 and 21 October, arrived in wintering areas in Mexico between 11 October and 3 November, departed from wintering areas from ≤6 to 21 April, and returned to Colorado between 15 and 21 May. Core wintering areas for three males were located in the Trans-Mexican Volcanic Belt Mountains in the states of Jalisco, Michoacan, and Puebla in central and east-central Mexico, and the core area for the other male was in the Sierra Madre Oriental Mountains in Tamaulipas. The mean distance from breeding to wintering centroids was 2057 ± 128 km (SE). During fall migration, two males took a southeastern path to eastern Mexico, and two males took a path due south to central Mexico. In contrast, during spring migration, all four males traveled north from Mexico along the Sierra Madre Oriental Mountains to the Rio Grande Valley and north through New Mexico. The first stopovers in fall and last stopovers in spring were the longest in duration for all males and located 300–400 km from breeding areas. Final spring stopovers may have allowed male Flammulated Owls to fine tune the timing of their return to high-elevation breeding areas where late snows are not uncommon. One male tracked in both years had similar migration routes, timing, and wintering areas each year. Core wintering and final stopover areas were located primarily in coniferous forests and woodlands, particularly pine-oak forests, suggesting that these are important habitats for Flammulated Owls throughout their annual cycle.