Clytoctantes atrogularis Lanyon, Stotz and Willard, 1990 (Thamnophilidae) is one of the most mysterious and poorly known birds of the Neotropics. Endemic to Amazonian Brazil, it was known only from the holotype and two sight records at the type locality in Rondônia, and a sighting of a pair with a recording on the Sucunduri River in Amazonas. Here we review the distribution and report five new records in the states of Mato Grosso, Amazonas, and Rondônia, considerably increasing the known range of the species. We present the first detailed descriptions of males, for which the plumage was previously unknown. The records presented herein were made in terra firme forest with understories dominated by Lepidocaryum palms and also with sparse Guadua spp. of bamboo, demonstrating that the bird species occurs in habitats other than those previously described. Stomach contents of six individuals included mostly ants and their eggs, possibly obtained by opening stems of Guadua spp. The high rate of deforestation that characterizes a large part of the range of C. atrogularis could be causing declines in local populations.

Phylogeographic analyses have hypothesized that Sclerurus (Furnariidae) populations of the rufous-throated clade (S. rufigularis and S. mexicanus sensu lato) have a long history of evolutionary isolation, particularly within the S. mexicanus complex (Tawny-throated Leaftosser). Although it has long been recognized that S. mexicanus should be split into two or more species, choosing between alternative species-delimitation schemes is much less clear due to minimal understanding of phenotypic variation and distributional range limits. We explored the extent of vocal variation between all described subspecies of S. mexicanus by analyzing spectral and temporal traits of songs and calls. We found five distinct vocal groups within S. mexicanus that differ primarily in their songs' maximum frequency, pace, and note shape. Specifically, we found that mexicanus, pullus, andinus, and obscurior each are vocally distinct from one another and from a group composed of macconnelli, peruvianus, and bahiae. Song traits of S. rufigularis overlapped with those of sympatric macconnelli and peruvianus and allopatric obscurior. The vocal distinctiveness patterns paralleled phylogeographic patterns and support a taxonomic scheme of treating S. mexicanus as five different species: S. mexicanus, S. pullus, S. obscurior, S. andinus, and S. macconnelli (including peruvianus and bahiae).

The critically endangered Hawaiian Crow or ′Alalā (Corvus hawaiiensis) is currently extinct in the wild and the remaining 115 individuals are being captively managed on Hawai′i and Maui Islands by the Zoological Society of San Diego. Here we provide the first comprehensive analysis of the vocal repertoire of this species. We documented the vocal repertoire of three male-female pairs of ′Alalā during the 2012 breeding season at the Keauhou Bird Conservation Center (KBCC) on Hawai'i Island. Vocalizations were recorded using an automated acoustic recorder placed outside each of three aviaries housing each pair of ′Alalā. A total of 44 hours of recordings were analyzed to describe the structure of vocalizations, call characteristics, and vocal repertoire of this species. We identified 24 different call type categories with fundamental frequencies between 500 Hz–2 kHz. Variation within each call type was observed, as well as variation of similar call types among ′Alalā breeding pairs. Many calls contained a variety of nonlinear dynamical states, including deterministic chaos, frequency jumps, bifurcation, and varying harmonics and subharmonics. These findings provide important baseline information on ′Alalā vocal behavior that may assist future efforts to release these birds back into the wild.

We present the first description of the breeding biology for the Fruithunter (Chlamydochaera jefferyi), a member of the cosmopolitan family Turdidae, and a montane endemic to the tropical Asian island of Borneo. We also compile breeding biology traits from the literature to make comparisons between the Fruithunter and the thrush genus Turdus. Our comparisons indicate that Fruithunters exhibit a slower life history strategy than both tropical and north temperate Turdus. We located and monitored 42 nests in 7 years in Kinabalu Park, Sabah, Malaysia. The mean clutch size was 1.89 ± 0.08 eggs, and the modal clutch size was 2 eggs. Mean fresh egg mass was 6.15 ± 0.13 g, representing 9.5% of adult female body mass. Average lengths of incubation and nestling periods were 14.56 ± 0.24 and 17.83 ± 0.31 days respectively. Only the female incubated and brooded the eggs and nestlings, but both the male and female fed nestlings. Female attentiveness during incubation was high throughout, reaching an asymptote around 85% with average on-bouts of 39.0 ± 2.5 mins. The daily nest survival probability was 0.951 ± 0.025, and the daily predation rate was 0.045 ± 0.024. Female feeding rate increased as brooding effort decreased, suggesting that female feeding rate may be constrained by the need to provide heat while nestlings are unable to thermoregulate. This contrasts with the feeding behavior of males, which showed much less of an increase across the nestling period. Furthermore, we describe a new vocalization which expands the vocal repertoire for Fruithunters, and we provide a brief audio clip and spectrogram.

Between 2013–2015, we conducted a study on the breeding biology of the Wren-like Rushbird (Phleocryptes melanops) in wetlands of the Pampas region, Argentina. The search for rushbird nests was conducted by several researchers walking into the wetlands, in three ways: by observing adults carrying material, through singing adults next to the nest or from the active search for nests in the vegetation. Nests were visited at intervals of 3–5 days. Of the 245 nests that we encountered (153 nests in 2013–2014 and 92 nests in 2014–2015), we found eggs in 97. The egg-laying period lasted almost 3 months (late Sept–late Dec). The mean clutch size was 2.7 ± 0.5 eggs (mean ± SD) (range = 1–3; n = 63), and the total nesting period was 34 ± 2.5 days (mean ± SD), with incubation and chick-rearing periods of 18 ± 1.63 days and 16 ± 0.50 days, respectively. From the total number of nests found, 43% of them were abandoned during building, 38% of nests were depredated, 14% of nests (n = 33) were successful, while 5% of nests were destroyed. Nest predation was higher during the incubation (80%) than during chick-rearing period (20%). The nesting success was on average of 23% (25% for the 2013–14 and 21% for the 2014–2015) for the entire nesting period. We also observed relatively higher plasticity than previously reported in relationship to vegetation used to fix nests (80% rushes, 20% other plants). Finally, we observed an abrupt termination of the reproductive period after desiccation of the wetlands; 90% of active nests failed (75% depredated and 25% abandoned) when the wetland was dried.

Manakins are small frugivorous birds found in the understory of humid Neotropical forests. Although aspects of their complex sexual displays have been addressed in various studies, their nesting biology is poorly documented. The Blue Manakin (Chiroxiphia caudata) is characterized by a cooperative courtship display but knowledge about its reproduction is limited to descriptions of the nest and eggs. We investigated 36 active nests during two breeding seasons in a well-preserved stretch of Atlantic Forest in southeastern Brazil. Nests were shallow cups attached at their rim to horizontal forks in bushes or saplings with slender branches and were usually built over or close to forest streams. Reproductive activities were recorded from October to February and clutches were invariably consisted of two eggs. The incubation period was 18 days; nestling periods varied from 15 to 16 days, and estimated overall nesting success was 34%. Comparisons of nest architecture, egg color, and nestling characteristics revealed important variations among the Pipridae, suggesting that these traits may not be diagnostic of genera and may not be informative in the phylogenetic reconstruction of the group. The duration of the breeding season is shorter than in manakin populations distributed near the equator and provides one of a few pieces of evidence of this tendency in the Neotropics. Our data support the findings that only females provide parental care in the Pipridae, which is hypothesized to be the result of a frugivorous diet.

Habitat modifications have led many bird species to occupy areas with different characteristics, including human-altered landscapes. In this study, we analyzed how land use influences the nest-site selection at the microscale level by Burrowing Owls (Athene cunicularia) breeding in vegetated sand dunes, periurban areas, and agroecosystems in the Pampas of Argentina. We compared the characteristics of the nest site (percentage of open space) and the nest patch (distance to conspecific nests, tall vegetation and perches and number of perches) within and among the three land-cover types. In addition, we evaluated the breeding performance (nesting success and productivity) of owls nesting in these land-cover types. We found that nest microsite variables did not vary between owl-occupied and owl-unoccupied sites within nest patches, but they differed among land-cover types. Although nest patches differed in their availability of perches at each land-cover type, distance from the nest to the nearest perch did not vary between them. Distances to tall vegetation and to conspecific nests were highly variable and did not differ among land-cover types. Our results indicate that Burrowing Owls that inhabit the Pampas used a variety of land-cover types for nesting and showed little selectivity of nest sites and nest patches, thus reinforcing the idea that they are habitat generalists.

The purpose of this study was to assess how bird communities are grouped in vegetation types between the breeding and non-breeding seasons in two consecutive years as well as the relationship between bird species' distribution and the main plant communities, all in a desert wetland in northern Mexico. We used transects to determine the bird species' abundances and the height and cover of vegetation to obtain three main variables: foliage height diversity, life form diversity, and total foliage density. Cluster analyses using the bird species' relative abundances grouped similar vegetation types, regardless of the geographic distance between them, during the breeding season but not in the non-reproductive season. This result suggests that birds occupy the various habitats in a random way during the non-reproductive season. Most of the bird species were closely related to the vegetation volume and foliage height diversity in both seasons, while the diversity of plant growth forms was of little importance.

Large-scale land-use change driven by residential development has degraded native ecosystems and altered the composition of species communities. Concern over the loss of habitat for human-sensitive species has led to questions about how housing impacts bird communities along the urban to rural gradient. Yet most studies of birds in residential ecosystems are limited to the breeding season, thus the effects of housing on avian habitat use in winter are not well understood. We surveyed winter resident birds, vegetation cover and structure, and human activity along a housing gradient in a Colorado landscape undergoing exurban development. Using an occupancy-based approach, we evaluated models for species with sufficient detections (n = 8). We found that habitat use by six species [American Robin (Turdus migratorius), Black-billed Magpie (Pica hudsonia), Dark-eyed Junco (Junco hyemalis), Downy Woodpecker (Picoides pubescens), Pygmy Nuthatch (Sitta pygmaea), Townsend's Solitaire (Myadestes townsendi)] was positively associated with housing density at scales ranging from 100–1,000 m. In contrast, habitat use by two species [Mountain Chickadee (Poecile gambeli) and Steller's Jay (Cyanocitta stelleri)] was negatively associated with housing proximity, and human activity had no effect on habitat use for any species. Canopy cover or understory vegetation cover and structure were important covariates for predicting habitat use of all species modeled. Our results suggest that to maximize the value of residential areas for a diverse wintering bird community, areas with natural vegetation should be incorporated into development planning. Overall, we found that the resident winter birds evaluated in our study were resilient to development in exurban areas. Indeed, these species may be opportunistic in occupying residential habitats that allow them to exploit anthropogenic resources during an energetically expensive time of year.

Great Salt Lake (GSL) is a critical migratory stopover location for Eared Grebes (Podiceps nigricollis), but the factors influencing the timing of their fall migration have not previously been investigated. We used archived Doppler radar data to visualize the nocturnal departures of Eared Grebes from GSL over 16 years, from 1999–2015. We used generalized linear models (GLMs) to examine interannual variability in the timing of migration of Eared Grebes in relation to prey availability and lake temperature, as well as variation in the nightly departure likelihoods of Eared Grebes in relation to weather. On average, Eared Grebes departed from GSL over a period of 31 days each year, with departures occurring on 17 of those days. We did not find any trend toward earlier departures over the years of the study. Departures typically began earlier in the year when densities of brine shrimp adults (Artemia franciscana) were higher than average, densities of brine shrimp cysts were lower than average, and lake temperatures were warmer than average. The span of migration departures was most strongly related to the day of first departure, with longer spans occurring in years with an earlier migration initiation day. We also found that likelihood of departure from GSL was greater on nights with high barometric pressure and low lake temperature. High barometric pressure was related to low wind speeds and low incidence of precipitation. We concluded that Eared Grebes depart when they have gained sufficient mass to successfully migrate rather than lingering at GSL for as long as possible, and that migration departure is most likely on nights with fair weather.

At the nest guild level, nest predation is a major cause of failure for many passerines. Species differ in behaviors that influence nest predation risk, presenting a challenge to nest survival analyses at the nest guild level. At our study site in southeastern New York, previous findings have suggested rodent nest predator abundance strongly drives daily nest survival of the Veery (Catharus fuscescens), a ground or low shrub-nesting songbird. In cue playback experiments, the sympatric ground-nesting Ovenbird (Seiurus aurocapilla) shows a greater aversion to chipmunk vocalizations than Veeries. These behavioral differences suggest these two sympatric ground-nesters may be driven by different ecological mechanisms despite similarity in their nesting niche. We examined how nest predator abundance, regional songbird abundance, and timing of nest activity during the breeding season influence nest survival in two songbirds from the same nest guild by building competitive models for determining the extrinsic drivers of daily nest survival. Ovenbird nest survival was best described by nest activity date, where nest survival decreased later in the breeding season, and was positively influenced by conspecific density. Nest survival of Veeries was strongly and negatively influenced by both nest predator abundance and regional abundance of Veeries. Thus, the strong relationship between nest predator abundance and nest survival observed in Veeries does not extend to Ovenbirds. These sympatric ground-nesting songbirds differ in how nest predators influence nest survival, therefore highlighting the importance of considering species-specific differences within nesting guilds to better understand nest survival at multiple ecological levels.

The detrimental effects of nest ectoparasites on breeding birds have been well documented, but interactions between birds' parasites and their environment are less well understood. The Saltmarsh Sparrow, Ammodramus caudacutus is a ground-nesting bird endemic to tidal wetlands in the eastern USA, where the majority of nests are lost to tidal flooding. This study examined evidence that Saltmarsh Sparrows face a trade-off between flood-risk and ectoparasite exposure in nest-site selection and nest initiation. We monitored nesting attempts during the breeding season, and collected 23 nests from which we extracted, described and analyzed the invertebrate communities. Many invertebrate taxa were present in nests, especially Acari, Amphipoda and Isopoda. Flooding-failure was by far the best predictor of nest parasite load (specifically Acari), superior to the investigated characteristics of habitat, nest construction, phenology and research methods. Nests that failed because of flooding had 15% fewer ectoparasites per gram of material. Nests made of smooth cordgrass, Spartina alterniflora had parasite loads 16% lower than those made of other materials, but this variable was confounded with flooding-failure. These results suggest that selecting flood-prone sites has benefits, by reducing exposure to ectoparasites, in addition to the often severe costs of flooding. This study improves understanding of bird nest-parasite interactions in a habitat in which they have been little studied.

In 2000, a resident population of Texas Seaside Sparrows (Ammodramus maritimus) was identified at Laguna Atascosa National Wildlife Refuge on the lower Texas coast, extending its known breeding distribution farther south than previously described. We studied this breeding population of Texas Seaside Sparrows from April 2012–January 2013 on the Laguna Atascosa National Wildlife Refuge to obtain population density estimates and describe habitat associations. We estimated seasonal density during one year using a distance sampling approach. We described plant community characteristics and estimated percent ground cover. Density estimates of Seaside Sparrows by season were 3.49/ha (CV = 8.27) for spring, 3.59/ha (CV = 18.16) for summer, 4.07/ha (CV = 9.69) for fall, and 1.91/ha (CV = 21.92) for winter. The dominant plant species along the intertidal zone transect where Seaside Sparrows were detected included turtleweed (aka saltwort; Batis maritima), saltgrass (Distichlis spicata), and bushy seaside tansy (aka sea oxeye daisy; Borrichia frutescens). Previous studies indicated cordgrasses (Spartina spp.) to be a dominant plant species strongly associated with Seaside Sparrows and a predictor of nest success. However, cordgrasses were absent from the intertidal zone where Seaside Sparrows were detected during our study. Habitat associations and conservation plans for Seaside Sparrows should be revised to include the plant community found in this study.

Sex differences in foraging behavior are typically studied in size-dimorphic taxa. Data on sex-specific behavior in monomorphic taxa are needed to test theories of reproductive investment. It has been suggested that in seabirds foraging niche separation may be related to decreased intersexual competition for food between cooperating pair-bonded individuals. Alternatively, sex differences in foraging niches may be driven by different nutritional requirements of females associated with the reproductive costs of egg production and oviposition. To assess these possibilities, we studied a size-monomorphic colonial seabird, the Australasian Gannet (Morus serrator) at the Cape Kidnappers gannetry, New Zealand. We recorded maximum dive depths, and distinct diet composition of incubating females as indicated by stable isotopic signatures. Results suggested greater female foraging effort during early times of incubation, indicated by significantly deeper maximum dives. Sex-specific foraging patterns across other breeding stages were more variable. Nitrogen stable isotopic values showed that incubating females occupied a different trophic position compared to males at the same breeding stage, and also from those of gannets of both sexes at later stages of parental care. Overall, the data are consistent with cost-of-oviposition compensation in females necessitating male-bias in parental care in biparental breeders. Further research is needed to unravel the implications of nutritional needs for the evolution of sex differences in behavior in this and other monomorphic taxa.

Bald Eagles (Haliaeetus leucocephalus) were rare only a few decades ago but have undergone a spectacular recovery range-wide. While their numbers have increased, there is concern about exposure of Bald Eagles to environmental contaminants. We collected excrement from nesting and wintering Bald Eagles in Iowa to examine their exposure to several contaminants and tested for differences as a function of space, time, and breeding status. We detected aluminum, copper, manganese, and zinc at levels above the quantitation limit (QL) in most excrement samples. These elements are all essential micronutrients normally found in living organisms. Arsenic and selenium are essential micronutrients for which fewer samples had levels above the QL. We also detected non-essential elements barium, cadmium, lead, and mercury in excrement samples, although only one sample had a cadmium level above the QL and only 26% of samples had lead levels above the QL. Geometric mean contaminant levels in excrement samples collected from nesting eagles during the spring were higher than for samples collected in the winter for aluminum, barium, copper, manganese, and zinc. The only difference we detected in contaminant levels in excrement samples was in manganese (higher for nest sites along the Mississippi River) and selenium (lower for nest sites along the Mississippi River) versus nest sites not associated with the Mississippi River. We also found that non-breeding eagles had higher levels of barium and manganese than nesting eagles. Our results can serve as a baseline for comparison with future studies investigating exposure of Bald Eagles to environmental contaminants.

We examined the fluorescence of ornaments among three auklet species: Least Auklets (Aethia pusilla), Crested Auklets (Aethia cristatella), and Parakeet Auklets (Aethia psittacula) on Gareloi Island, Alaska during the 2015 breeding season. We found that the ornamental bill plates of Crested Auklets fluoresced, but bill ornaments of Least Auklets and bills of Parakeet Auklets did not. We also found that none of the feathers in these three species exhibited fluorescence. We suggest that differences in ornamentation and fluorescence may be related to life-history strategies associated with sexual selection and predator avoidance.

Bird plumage coloration is an important signal used in communication and may indicate individual fitness. We tested the hypothesis that coloration is related to body condition in male Helmeted Manakins (Antilophia galeata). Fourteen adult males were captured in a forest fragment in Brazilian Cerrado from November 2007 to June 2008. Crown feather coloration (brightness, hue, and saturation) was evaluated through spectrophotometry, and body condition was measured via the Relative Mass Index (RMI). Coloration characteristics were positively correlated with body condition, indicating that individuals with higher body conditions have brighter and more saturated feathers, and therefore, can use these traits to signal their good body condition.

Soft-part coloration can be a useful method for determining the age of a bird. For example, hatch-year and early second-year Mangrove Cuckoos (Coccyzus minor) are supposedly distinguishable from older birds based on the presence of a dusky gray eye-ring; individuals gain a vivid yellow eye-ring in their second year of life that they retain for the rest of adulthood. However, observational data collected on banded Mangrove Cuckoos throughout the year indicate that eye-ring coloration varies seasonally rather than with age. We captured and banded two individuals in early spring, each with a yellow eye-ring. Re-sightings of these individuals later in the spring and early summer revealed that the eye-ring had changed to a dusky gray color. Subsequent re-sightings of these individuals again in the fall and winter revealed that both once again had a yellow eye ring. In reviewing photographs and notes taken during observation of marked and unmarked individuals, we determined that this pattern—a yellow eye-ring during late summer, fall, and winter (nonbreeding) and a dusky-gray eye-ring during spring and early summer (breeding)—was consistent across individuals in the population in Florida that we studied.

Bird ornaments, such as plumage and song, can reflect the age of individuals. Knowledge of an individual's age and potential past breeding experience is important to future mates and to scientists studying mate-choice decisions, levels of parental investment, and reproductive performance. The iridescent length of hackles (throat feathers) has been used to sex and age adult European Starlings (Sturnus vulgaris). We confirmed that males have longer portions of hackle iridescence and overall longer hackles than females. Although After Second Year (ASY) adults have longer hackle iridescence than Second Year (SY) adults, only two other studies that we know of have examined the iridescent length of hackles in the same individuals over time. We measured hackle iridescent length of returning adults over 8 years, and discovered that it continues to increase with age in both females (25/26) and males (21/21). It had the greatest increase over the 1-year period when breeding adults switched from the SY to the ASY age category. Total hackle length also continued to increase with age, albeit more reliably for males (18/21) than females (13/26). These results demonstrate that hackle iridescence is a potential signal of age throughout the lifespan of a European Starling.

The geographic distribution of the non-migratory Gray-headed Chickadee (Poecile cinctus) straddles the continents of North America and Eurasia. Morphological variation in this species has been poorly studied, particularly regarding differences between Nearctic and adjacent Palearctic populations (subspecies lathami and cinctus, respectively). To evaluate geographic patterns of morphological variation between lathami and cinctus, we measured 24 variables related to coloration and structure on 24 museum specimens. We found statistically significant average differences between specimens of lathami and cinctus in three plumage areas and three measures of bill size. Genetic analysis is needed to further quantify divergence in lathami.

The hormones prolactin (PRL) and testosterone (T) are linked to breeding behaviors such as territory defense, incubation, and brood-rearing in birds. The Mountain Plover (Charadrius montanus) is a shorebird with an uncommon parental care system in which males and females tend separate nests. We collected blood from incubating male (n = 38) and female (n = 33) Mountain Plovers in Montana to determine how circulating plasma PRL and T varied by sex, day of incubation, and across the nesting season. PRL levels were similar in males and females. There was no relationship between day of incubation or Julian day and circulating PRL for either sex. T concentrations were higher in males than in females and tended to decrease across the incubation season for both sexes.

Wild Amazonian parrots likely consume soil to supplement sodium-deficient diets. However, it remains uncertain whether parrots can detect sodium at the concentrations found in mineral licks. During 3–8 day trials, we presented 20 captive Hispaniolan Amazon Parrots (Amazona ventralis) two foods with experimentally manipulated sodium concentrations. Parrots consumed more of the lower sodium food, confirming that they could distinguish between 891 ppm and 1,644 ppm available sodium—values well within the range of concentrations found in mineral licks in the wild. This study strongly suggests that wild parrots can use taste to detect salty soil horizons in the Amazon.

Until recently, species from all but three families of seabirds were known to give extended parental care, provisioning young after fledging. The exceptions were shearwaters, storm-petrels, and penguins. The Gentoo Penguin (Pygoscelis papua) is now known to feed its young after fledging. This paper adds the Galapagos Penguin (Spheniscus mendiculus) to the list, describing five instances of adult provisioning of recently fledged Galapagos Penguin chicks. All feedings were on land and in the afternoon or early evening. Extended parental care is rare in penguins and should occur only if 1) provisioning does not harm adult body condition or conflict with molting, 2) food is available close to the colony, and 3) adults and fledglings return to the nest area after the chicks fledge and before their dispersal from the colony. These requirements suggest it is unlikely that other penguin species commonly feed chicks after they fledge.

We studied the diet of Crested Guans (Penelope purpurascens; Galliformes: Cracidae) in lowland tropical forest on Barro Colorado Island, Panama. From June-August 2015 we collected observations of foraging adults using five-minute focal follows of randomly chosen individuals. A total of 141 food items were recorded over 565 minutes of observations. Although Crested Guans are believed to be primarily frugivorous, we found that they consumed a high proportion of leaves (61.7% of items) and insects (24.8%), with fruits comprising a minority of items (13.5%). Guans preferred to eat young leaves, which are more tender and contain higher levels of nitrogen than mature leaves; however, young leaves also contain higher levels of tannins and other secondary defensive compounds, raising new questions about the mechanisms by which arboreal birds digest leaves. Recent studies have found similarly high levels of leaf consumption in other species of guans and chachalacas, suggesting that folivory may be more widespread in the family Cracidae than previously realized.

The Common Raven (Corvus corax) is a ubiquitous species in the Mojave Desert of southern Nevada and California. From 5 to 24 May 2014, using remote trail cameras, we observed ravens repeatedly kleptoparasitizing food resources from the nest of a pair of Golden Eagles (Aquila chyrsaetos) in the Spring Mountains of southern Nevada. The ravens fed on nine (30%) of the 30 prey items delivered to the nest during the chick rearing period. Kleptoparasitic behavior by the ravens decreased as the eagle nestling matured to seven weeks of age, suggesting a narrow temporal window in which ravens can successfully engage in kleptoparasitic behavior at eagle nests. The observation of kleptoparasitism by Common Ravens at the nest suggests potential risks to young Golden Eagles from Common Ravens.

The Subtropical Doradito (Pseudocolopteryx acutipennis) is a small tyrannid that breeds in shrubby marshlands of South America. Post-breeding migration occurs in both mountain and lowland populations, but little is known of the destination(s) of these birds. Subtropical Doraditos have recently been found during the southern winter, or non-breeding season, in several localities in southern Amazonian Brazil and the Pantanal, with four reports from coastal Brazil. Our observations and censuses in coastal marshes of southeast and southern Brazil have produced eight records of Subtropical Doradito in the states of Paraná and São Paulo. In light of comparison with other Brazilian records compiled for this study, we suggest that coastal winterers are likely latitudinal migrants from geographically restricted breeding grounds in the Pampas of Argentina. In addition, we discuss conservation problems for the Subtropical Doradito in coastal wintering areas.

The genus Chlorochrysa, with three species: C. phoenicotis, C. calliparaea, and C. nitidissima, is distributed throughout the Andes from Colombia to northern Bolivia inhabiting mossy cloud forests between 900–2400 m. We describe for the first time the reproductive biology of the C. nitidissima and the use of different nesting sites. This study was conducted at three sites located on the eastern slope of the Western Cordillera in Colombia. The shallow cup nests were built with small thin sticks and dry bamboo leaves, placed inside hanging mossy clumps located on horizontal branches or inside abandoned dome-shaped songbird nests. We report a clutch size of one white, oval egg with brown spots, which measured 21.45 × 15.0 mm and weighted 2.3 g (n = 2). The average nestling period was 23 days, and the nestling growth rate (K) was, on average, 0.29. Finally, these results could be used to implement plans for the conservation of this endemic and critical endangered species.

Although polygyny is common and regular among a small proportion of North American songbirds, some socially monogamous passerines may also exhibit occasional polygyny. We present evidence for only the second documented case of polygyny within the Vireonidae and the first documentation for polygyny in the endangered songbird the Black-capped Vireo (Vireo atricapilla). We located two simultaneous nests being tended by the same color-banded male vireo in a territory adjacent to an unpaired male. We suspect that differences in territory quality, rather than male quality, unbalanced sex ratios, or asynchronous settlement, were drivers of polygyny in this example.

Nest collapse has been documented in many bird species, with little discussion of adult behavior following collapse. We present evidence of a partial collapse of a Gyrfalcon (Falco rusticolus) nest during the nestling period and the subsequent adult response. A nest camera captured the nest collapse and showed one adult Gyrfalcon holding a live nestling in its beak before leaving the nest. Later, we found the surviving nestling alive in an alternate nest 5 m from the original nest, presumably transported there by the adult. We believe this is the first report of an adult Gyrfalcon moving a nestling to a new location following nest disturbance. We place this observation into a context of Gyrfalcon nesting behavior described in published sources. The continued use of nest cameras may provide additional documentation and insight into this behavior and its prevalence in birds.