Adults and juveniles of some forest breeding birds shift habitat use during the post breeding season from late to early successional forest. Juveniles of smaller passerine species are difficult to radio-track, and there is limited information on their habitat preferences, especially once they become older and independent. We determined if independent hatch-year birds captured in early-successional habitat remained there for extended periods, or if these habitats were only occupied infrequently during foraging activities. We determined habitat use for Ovenbirds (Seiurus aurocapilla), Worm-eating Warblers (Helmitheros vermivorum) and Red-eyed Vireos (Vireo olivaceus) during the independent post-fledging period in the Missouri Ozarks. We placed radio transmitters on 29 hatch-year birds captured in clearcuts and attempted to relocate them for 24 days in the summer of 2012. All three species had a greater relative probability of use of clearcut forest stands with small trees than older forests. Ovenbirds and Worm-eating Warblers remained in the early-successional habitat where initially captured, whereas Red-eyed Vireos used both late and early-successional habitat. Management efforts have primarily focused on breeding habitat for migratory songbirds, but the post-breeding period could be equally important given that hatch-year birds can spend an equal or greater amount of time in this stage. More information is needed to determine how widespread this habitat shift is for mature forest-breeding birds.

Over the last two centuries, a large and increasing number of non-native phytophagous insect species have become established in North America. In addition to the direct effects these insects have on their new host plants, indirect effects such as changes in community composition, community structure, and resource abundance have been reported. We investigated the indirect effects of viburnum leaf beetle (Pyrrhalta viburni), a Eurasian native, on a landbird community using shrubland habitat during spring migration. We compared avian community composition and bird mass before and after viburnum leaf beetles invaded our site. Before invasion, southern arrowwoods (Viburnum dentatum) were a prominent native component of the vegetation community. Not only was the avian community more diverse prior to infestation, our estimates from this period also suggest seven of nine species examined gained mass, and most did so at high rates. The avian community was less diverse after beetle infestation, and capture rates for seven of 69 species dropped significantly while capture rate of one species increased significantly. Finally, after infestation we found that no bird species showed evidence of mass gain. Given the decline of early successional habitats in eastern North America and the significance of early successional habitats to both birds that breed in these habitats as well as forest breeding birds during nonbreeding phases of the annual cycle, degradation of these habitats by invasive insects may have a larger effect than previously realized.

Many species of songbirds in the United States have shown widespread declines in population numbers during the last five decades. To understand ongoing declines and plan for conservation, researchers need reliable estimates of adult survival and site fidelity. However, variation in adult survival and site fidelity within and among species is substantial and could have consequences for management. Estimates of adult survival are lacking for many bird species and ecoregions, including the Great Plains. In this field study, we used Cormack-Jolly-Seber mark-recapture models to analyze encounter histories of 17 species of birds captured with a 13-year systematic mist-netting effort in northeast Kansas. We estimated annual rates of apparent adult survival (φ) and corrected for the probability of capture (p), and tested for effects of sex and breeding habitat guild. We present the first estimates of apparent survival for six species of songbirds, and the first estimates from the Great Plains for 13 species. Apparent survival tended to be higher for males than for females, and we found a sex effect on the probability of capture for one species. Unexpectedly, grassland- and shrubland-breeding species had higher estimates of apparent survival than forest-breeding species. Our results did not support the prevailing viewpoint that birds breeding in dynamic landscapes, such as frequently burned grasslands, should show lower apparent survival than species that breed in woody habitats. We demonstrate that habitat plays an important role in the survival and site fidelity of songbirds, and that regional differences in habitat structure could drive variation in demography. Understanding the drivers of true survival and site fidelity of songbirds will allow region-specific management for species of conservation concern.

Throughout North America, organized groups of citizens and scientists have collected climate and bird phenology records since the 1880s. Most studies utilizing these data sets have compared mean first arrival dates but have not compared trends between historical and more contemporary data sets. We analyzed spring first arrival dates and fall last departure dates for 39 migrant bird species across three different data sets spanning a historical period when there was little climate change (1888–1939) and a contemporary period during which significant climate warming occurred (1967–2012). During the historical period, there was little change in first arrival dates through time. In contrast during the contemporary period, there was a significant advance in first arrival date from early years to later years. During both the historical and contemporary periods, short-distance migrants reached the breeding grounds earlier than long-distance migrants, and the magnitude of this difference was consistent between periods. During the contemporary period, we found evidence for an increase in breeding season length among 4 of the 39 species studied. Our results suggest that changes in the phenology of migratory bird species in New York are a recent phenomenon associated with a period of climate warming beginning in the mid 1970s and extending through today, but earlier arrival does not appear to be leading to an increase in breeding season length for the majority of species.

Mechanisms underlying habitat use in most species are poorly understood. Therefore, we integrated behavioral and forest cover type data to test hypotheses underlying the choice of two key cover types used by male Ruffed Grouse (Bonasa umbellus) in northern Minnesota, USA. Forests of aspen (Populus spp.) are the presumptive highest quality cover type for Ruffed Grouse because this bird species achieves its highest breeding densities in this cover type. Yet, males select cover types of conifer even when nearby cover types of aspen remain vacant. We examined this conundrum – selection of inferior cover types when presumed better types are available – by randomly selecting 23 male Ruffed Grouse from among a contiguous population of territorial males and used automated video systems to monitor their breeding display behavior. We predicted that if conifer cover types were indeed inferior habitat for Ruffed Grouse, males that established territories in these cover types would either drum (auditory display) more frequently to attract mates or have fewer conspecific interactions, detected by observing visual display rates, than males which established territories in aspen cover types. We used drumming rates and visual display rates as two separate response variables, and used generalized linear models to evaluate each of these response variables as a function of several predictors in a priori models including cover type, male density on the study area, distance to the nearest neighbor, cover type of the nearest neighbor, and distance to the nearest neighbor in aspen cover. Information-theoretic model selection was used to rank these models with Akaike's Information Criterion adjusted for small sample sizes. The best predictor (top model) of drumming rates among our model set, was cover type, but our null model was competitive, which suggested uncertainty in our result. We were unable to explain visual display rates given our model set and predictor variables, because our intercept only [null] model was the top model, which suggested visual display behavior was not correlated with either cover type or the other factors we included in models. We conclude the reason grouse select display sites likely has more to do with suitable protective cover (i.e., predator avoidance) than with the general classification (aspen vs. conifer) of the cover type. Thus, the link between relative fitness and habitat selection of specific cover types is more likely to be revealed by studying the habitat requirements and survival probabilities of females visiting males which occupy these two prominent breeding-display covers.

In order to understand evolution in life history strategies, it is useful to compare breeding parameters among closely related species and/or different habitats within the same species. The Paridae family, known as tits and chickadees, are suitable for such studies since they are distributed worldwide and use a variety of habitats. However, previous studies are mostly limited to populations in Europe and North America. Few studies have compared breeding biology in sympatric Paridae species. In this study, we investigated the breeding biology of Japanese Tits (Parus minor), Coal Tits (Periparus ater), Marsh Tits (Poecile palustris), and Varied Tits (Sittiparus varius) in a cool temperate forest of northern Japan. A previous study has shown that Japanese Tits have higher annual production (i.e., clutch size, rate of multiple brooding) compared to a European sister species, the Great Tit (Parus major), possibly because of greater diversity and abundance of prey items. Therefore, we predicted that annual breeding productivity should also be high in the other sympatric species. Contrary to the expectation, annual productivities were not high for the other species with few or no second clutches, indicating the lack of a general rule of high food availability in this region. Some ecological or physiological constraints may exist for other species, such as trade-offs involving survival versus fecundity or resident versus migrant. This study provides basic but important information on breeding biology of Paridae in understudied Asian populations.

Juvenile birds are generally less efficient foragers than adults, and this can lead to reduced survival or delayed reproduction. Feeding on hard-shelled nuts and mollusks after breaking them open by dropping is particularly challenging. To determine whether juvenile birds are as proficient as adults at this complex foraging task, we compared juvenile and adult Herring Gulls (Larus argentatus) feeding at low tide by dropping clams (Rangia cuneata) at a coastal estuary in Virginia, USA. Juvenile (first-winter) gulls were less successful than adult (2 years old) birds at finding clams to drop. Moreover, the clams they selected were of a wider range of sizes, more often being difficult to handle or of lower nutritional value. Juveniles did, however, drop clams with the same degree of success as adult birds. Together these results suggest that learning to find and recognize profitable clams is the developmental bottleneck in this complex behavior.

The Black-headed Duck (Heteronetta atricapilla) is a unique interspecific brood parasite among birds where the host species provides parental care for incubation only. Despite this unique system, there are few studies on this species biology and the list of hosts remains incomplete. We present information about breeding phenology of the Black-headed Duck and an updated list of hosts obtained from a comprehensive review of egg collections deposited in the most important natural science museums of Argentina. We include five new hosts to the list: Great Grebe (Podiceps major), Maguari Stork (Ciconia maguari), White-cheeked Pintail (Anas bahamensis), South American Stilt (Himantopus mexicanus), and Long-winged Harrier (Circus buffoni). We found that solitary nesting host species were more likely to be parasitized earlier during the breeding season than colonial nesting species. The Black-headed Duck has an extended breeding season in central Argentina (Aug–Feb) as it is able to use a variety of hosts that breed in different times during the breeding season. With this contribution, the new list rises to 23 documented hosts of the Black-headed Duck belonging to eight different waterfowl orders.

Sexual dimorphism in birds may express itself as differences in body size, plumage, color and/or behavior. Many species are monomorphic in color, which makes sex determination difficult in the field. In order to develop a tool to distinguish between male and female specimens of the White-faced Ibis, Plegadis chihi, by using external body measurements, the objective of this work was to quantify morphometric differences between sexes in adults of this species. The following variables were measured: culmen length, bill height and width, tarsus length, middle toe (with claw) length, wing chord, tail length and body mass. Males were larger than females in all of these variables, and presented statistically significant differences for six out of eight parameters. Three discriminant classification functions were obtained with an accurate total classification rate in >85% of the cases. The length of the culmen, tarsus, middle toe with claw, and wing chord, were among the most useful variables to discriminate between sexes. The classification functions are useful for the discrimination of sexes in the White-faced Ibis, with easy-to-take measurements. This information may be used by avian ecologists in future behavioral ecology, conservation biology, or evolutionary biology studies. The use of external morphometrics to sex monomorphic birds is of great value, being an inexpensive, less invasive and more immediate method.

Cranes usually roost in shallow water, while large numbers of cranes roosting in a waterless environment are rarely reported. We document novel upland roosts used by the Black-necked Crane (Grus nigricollis) wintering at Yongshan in northeast Yunnan, China. A total of 45 upland roost sites were recorded in the winters of 2012–2013 and 2013–2014. The roost sites were on upper slope positions (0.74 ± 0.17, 0.34–1.00) of steep mountain slopes (28 ± 5°, 20–40°) above stream valleys, with the roost at 95 ± 30 m, 32–175 m from the foot of its hill, and often had a platform or flat space (21 out of 45). The roost sites occurred in three habitats: shrub forest, grassy terrace, and natural grassland-bare land. We found that the pattern of roost site use is different from that of Black-necked Cranes in other wintering areas, as well as that of other species in the family Gruidae. This discovery suggests Black-necked Cranes may be more flexible and less reliant on wetlands for nocturnal roost use than we previously perceived. Further research on roost selection is needed to more thoroughly understand the behavior of the Black-necked Crane and for the conservation and management of this species.

We review 147 incidents of the capture of small birds by mantids (order Mantodea, family Mantidae). This has been documented in 13 different countries, on all continents except Antarctica. We found records of predation on birds by 12 mantid species (in the genera Coptopteryx, Hierodula, Mantis, Miomantis, Polyspilota, Sphodromantis, Stagmatoptera, Stagmomantis, and Tenodera). Small birds in the orders Apodiformes and Passeriformes, representing 24 identified species from 14 families (Acanthizidae, Acrocephalidae, Certhiidae, Estrildidae, Maluridae, Meliphagidae, Muscicapidae, Nectariniidae, Parulidae, Phylloscopidae, Scotocercidae, Trochilidae, Tyrannidae, and Vireonidae), were found as prey. Most reports (>70% of observed incidents) are from the USA, where mantids have often been seen capturing hummingbirds attracted to food sources in gardens, i.e., hummingbird feeders or hummingbird-pollinated plants. The Ruby-throated Hummingbird (Archilochus colubris) was the species most frequently reported to be captured by mantids. Captures were reported also from Canada, Central America, and South America. In Africa, Asia, Australia, and Europe, we found 29 records of small passerine birds captured by mantids. Of the birds captured, 78% were killed and eaten by the mantids, 2% succeeded in escaping on their own, and 18% were freed by humans. In North America, native and non-native mantids were engaged in bird predation. Our compilation suggests that praying mantises frequently prey on hummingbirds in gardens in North America; therefore, we suggest caution in use of large-sized mantids, particularly non-native mantids, in gardens for insect pest control.

The Vegetarian Finch, Platyspiza crassirostris, is a relatively unstudied Darwin's finch that appears to be in decline in the Galapagos Islands. We monitored 11 nests of Vegetarian Finches during 2013 and 2014 on Santa Cruz Island, Galapagos, and found that 10 of these were infested with an invasive parasitic fly, Philornis downsi. This is the first report of P. downsi attacking this bird species. The number of P. downsi in nests of Vegetarian Finches was higher than for other Darwin's finch species, but nestling mortality was relatively low. We hypothesize that both of these trends may be related to fact that the Vegetarian Finch is one of the largest-bodied species of Darwin's finches. We also consider the conservation implications of P. downsi parasitism for populations of vegetarian finches and other Darwin's finch species in the Galapagos Islands.

Ornithologists have observed migratory landbirds from offshore ships for over a century. These birds are often in poor condition and thrown off course by storms. We report observations of migratory landbirds on a research vessel that was 320 km offshore in the western North Atlantic Ocean, shortly after Hurricane Gonzalo moved through the area. Between 19 and 25 October 2014, we observed nine passerine species and one falcon species. Two of these passerine species have not previously been observed on offshore ships. We also describe passerine and falcon foraging behaviors that have not been reported before. We examined six passerine birds found dead on the ship and concluded that they likely died of starvation and exhaustion. The passerines we observed may have been disturbed by Hurricane Gonzalo, forcing birds in poor condition to land on the ship. We encourage ornithologists to publish offshore accounts of migratory landbirds to improve our understanding of avian migration.

Nest tenacity, defined as the persistence of an individual to continue nesting during and/or following a disturbance, can be an important behavior to influence reproductive potential of individuals and species. Anthropogenic disturbance is a known cause of nest abandonment or destruction, and nest tenacity may be a coping mechanism in response to this source of disturbance. We observed nest tenacity behavior in a female Scaled Quail (Callipepla squamata) that initiated a nest on 3 July 2013 near Beaver River Wildlife Management Area, Beaver County, Oklahoma, USA. Ten days into nest incubation, roadside mowing occurred that removed all overhead protective vegetation. Ambient temperatures exceeded 35 °C (the ambient temperature in which Scaled Quail become hyperthermic) on 8 days following the disturbance. However, the female continued to incubate the exposed nest for another 15 days, despite potential thermal stress and being located 7.5 m from a county road with moderate vehicle traffic. This observation indicates that Scaled Quail, a species for which we have limited information on breeding behavior, can exhibit strong nest tenacity.

Global change can affect several aspects of bird biology, including population size and migration timing. We used count data collected during 25 years (1990–2014) at Hawk Mountain Sanctuary, a raptor migration watch-site in eastern Pennsylvania, to investigate population changes in Ruby-throated Hummingbirds (Archilochus colubris) and the timing of their autumn migration, in light of ongoing climate change. Hummingbird numbers increased significantly from 1990–2014. The first 5%-, 50%-, 95%- and average passage dates of hummingbirds over this time indicated an earlier passage, with the first 5% passage-date shifting earlier significantly. Passage duration (number of days between 5% and 95% of the flight) remained relatively constant from 1990–2014. In light of similar shifts in timing of spring passage of this species, our results suggest that Ruby-throated Hummingbirds may be shifting the timing of their migratory cycle.

Harris's Hawks (Parabuteo unicinctus) are cooperative breeders, and groups of more than a pair have been reported from Arizona (49% to 83%) and New Mexico (51%). However, two studies (Griffin 1976, Brannon 1980) suggested that they breed in groups infrequently in Texas (5% and 13%). During a banding study from 2004–2014, I occasionally captured three or more adults at the same time and place, and I regularly observed groups of three or more adults. I undertook a study to determine sizes of breeding groups in south Texas in 2014 and 2015 in a mix of breeding habitats, primarily thorn scrub forest, but also parks, agriculture with forest and grassy plots, industrial areas, and urban areas. I determined that more than half (56%) of the 73 breeding groups I observed in south Texas were composed of three or more individuals, contrary to the results of the two earlier Texas studies, which may have underestimated group size because of fewer short visits compared to longer visits spent determining group size in this study.

I observed male Red-winged Blackbirds (Agelaius phoeniceus) defend and provision nests, and I documented survival of pair-fed and female-fed broods to determine whether male parental behavior affects nestling survival and nest success. Broods provisioned by both males and females (n = 208) had significantly higher daily survival and were significantly more likely to produce fledglings than those fed only by females (n = 268). Examination of male responses to a crow model during incubation (n = 114) showed that males were more aggressive towards the simulated predator at nests they would later provision than at nests fed only by females. These results show that male provisioning is associated with more aggressive nest defense and increased nestling and nest survival, and suggest that parental behavior of male Red-winged Blackbirds is both plastic and adaptive.

In spite of its relevance, data on nest architecture and egg morphology are lacking for several bird species, especially in the Neotropics. We provide the first egg and standardized nest description of the Southern Bristle-Tyrant (Phylloscartes eximius), a species considered in the genus Pogonotriccus by some authors. Similarly to two other studies, the nest was a closed/globular/lateral structure built mostly with moss and spider web. The only egg we found was clean white and measured 17.1 mm length x 13.5 mm width. Given the plasticity of nest building and the low sample size, more nests should be described to infer relatedness among Phylloscartes and Pogonotriccus using nest architecture. Similarly, more eggs of these species should be described.

The Choco Screech-Owl (Megascops guatemalae centralis) is one of the rarest birds in Ecuador and its taxonomy remains poorly understood. Here, we describe the nest, owlet morphology, prey items, defensive behaviors, a newly discovered locality for the species, and the occurrence of parasitism, caused by Philornis sp. of the owlets.

The Wedge-billed Woodcreeper (Glyphorynchus spirurus) is a common suboscine passerine of lowland forests of the Neotropics. While nest sites and incubation behavior for the species have been described, information about courtship and fledgling care are absent. As part of a separate study on the movement patterns of Wedge-billed Woodcreepers in eastern Ecuador, we observed a previously undescribed display behavior and collected data on fledgling feeding rates. We observed a neck-extension behavior performed synchronously by two interacting individuals that appears to play a role in courtship, but is also performed in aggressive contexts. Given that only 5 of 23 tracked adults were known to be breeding during the study period (Jan–Apr 2012), it is likely that the breeding season in this area extends well before and after this time period. Molt and breeding activities coincided for two individuals. Fledgling feeding rates ranged from 0.47–2.0 feeds/hr for adults from three nests; observation of only one fledgling (whereas two nestlings are typical) with each tracked adult might indicate brood splitting soon after fledging.

We recently reported observations of Common Ravens (Corvus corax) eating eggs, juveniles, and possibly adult Rhinoceros Auklets (Cerorhinca monocerata) on Protection Island National Wildlife Refuge, Jefferson County, Washington. In this new report from 2015, we found 32 eggs presumably eaten by ravens, which represents a 16-fold increase during the same time window of the breeding season of 2014. In addition, we report on one attempted and one observed kleptoparasitism (food piracy) event by Bald Eagles (Haliaeetus leucocephalus). An adult eagle was observed chasing a raven carrying a recently caught egg in its mandibles. In a second instance, an immature eagle stole and ate an egg that was being eaten by a raven. It is currently unknown if the combination of increased feeding by Common Ravens on Rhinoceros Auklets, and kleptoparasitism by Bald Eagles stealing recently captured auklet eggs from ravens influences predation pressure on the auklet colony at Protection Island.

During 2011, four separate instances of indirect filial cannibalism, whereby adults consumed their young that died from unknown causes, were observed using video-monitoring techniques in a nesting colony of Black-crowned Night-Herons (Nycticorax nycticorax) on Alcatraz Island. Though they were not observed actively killing their young, in all four observations adult Black-crowned Night-Herons consumed their young following death (i.e., indirect filial cannibalism). We could not determine cause of chick mortality, but parental neglect was likely a contributing factor in at least two instances. Indirect filial cannibalism is not commonly documented among birds, and understanding how cannibalism contributes to nest failure can help researchers better understand factors that limit nesting populations.

I report predation by American Crows (Corvus brachyrhynchos) on little brown bats (Myotis lucifugus) near the entrance to an abandoned mine and below ground within the mine in the Upper Peninsula of Michigan. This appears to be the first report of a corvid repeatedly entering a cave or mine to pursue prey and provides additional evidence for the remarkable behavioral plasticity of this species and family.

The Brown Dipper (Cinclus pallasi) was discovered to be a regular winter resident in the mountains of Verkhoyansk Range in Northeastern Siberia. This area is one of the coldest in the Northern Hemisphere, with winter temperatures normally staying around −50 °C and occasionally dropping below −65 °C. Despite the extreme cold, the birds exhibited normal foraging behavior. Precise breeding locations of these dippers, wintering almost 200 km NW from the species' known range, remain unknown.

We describe the isolation of 10 microsatellite loci with tetranucleotide repeat motifs from the Orange-crowned Warbler (Oreothlypis celata) by using an enrichment protocol. All 10 loci were variable across two sampled populations (Alaska, California Channel Islands); the number of alleles ranged from 2–23, and observed heterozygosity ranged from 0.333–1.000. We tested the utility of these loci across an additional 13 parulid species, spanning the evolutionary and ecological diversity of the Parulidae. Nine of our 10 primer pairs were successfully PCR-amplified across at least 12 species, with the remaining locus being amplified across 9 parulid species. We expect the identified loci to be of particular use in studies of phylogeography, determination of cryptic species boundaries, hybrid zone dynamics, and paternity assignment across New World warblers.

Fourteen microsatellite loci were characterized for the Rufous-throated Antbird (Thamnophilidae: Gymnopithys rufigula), an Amazonian obligate ant-following bird. Eight novel polymorphic microsatellite loci were isolated using next-generation sequencing and six additional loci were cross-amplified using primers previously designed for other bird species. All 14 loci were screened using 40 samples from central Amazon. The number of alleles per locus ranged from 3 to 20, whilst the observed and expected heterozygosities varied from 0.200 to 0.975, and 0.186 to 0.928, respectively. No linkage disequilibrium was found among the loci. Only one locus deviated from Hardy-Weinberg equilibrium. Among the eight novel loci, six were cross-amplified in at least one additional Thamnophilidae species, whilst three loci cross-amplified in two other Dendrocolaptidae species. This set of markers will be useful for future population genetic structure and parentage analysis of Amazonian forest birds.

A carcass of a House Swift (Apus nipalensis) found in Ladner, British Columbia on 18 May 2012 appears to be the first documented record of this species in the Americas. Identification is based on DNA sequencing and morphometric characters. University of British Columbia Beaty Biodiversity Museum Cowan Tetrapod Collection catalogue number B017056 has been assigned to this specimen (round study skin, spread wing, partial skeleton, and tissue samples).

On 10 April 2016, I observed a Pied-billed Grebe engage in a terrestrial foraging bout to capture a large earthworm. All members of the grebe order (Podicipediformes) are aquatic foraging species with lobate toes on feet positioned towards the posterior portion of the body. Grebes are accomplished divers and typically consume prey captured underwater. There had been no recorded instances of any grebe foraging on land prior to this observational account.