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Innovations in nest design are thought to be one potential factor in the evolutionary success of passerine birds (order: Passeriformes), which colonized new ecological niches as they diversified in the Oligocene and Miocene. In particular, tyrant flycatchers and their allies (parvorder: Tyrannida) are an extremely diverse group of New World suboscine passerines occupying a wide range of habitats and exhibiting substantial extant variation in nest design. To explore the evolution of nest architecture in this clade, we first described nest traits across the Tyrannida phylogeny and estimated ancestral nest conditions. We then quantified macroevolutionary transition rates between nest types, examined a potential coevolutionary relationship between nest type and habitat, and used phylogenetic mixed models to determine possible ecological and environmental correlates of nest design. The Tyrannida ancestor probably built a cup nest in a closed habitat, and dome nests independently evolved at least 15 times within this group. Both cup- and dome-nesting species diversified into semi-open and open habitats, and we did not detect a coevolutionary relationship between nest type and habitat. Furthermore, nest type was not significantly correlated with several key ecological, life-history and environmental traits, suggesting that broad variation in Tyrannida nest architecture may not easily be explained by a single factor. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'. [ABSTRACT FROM AUTHOR]

The Southern Streaked Flycatcher (Myiodynastesmaculatus solitarius) is a common Neotropical austral migrant that breeds in both rural and urban environments of southeastern Brazil, providing a model to understand how songbirds are responding to an increasingly urban landscape in this region of the continent. We evaluated whether breeding site fidelity is related to sex and habitat type (urban versus rural). Because the annual cycle of migratory birds provides context to breeding season processes, we also described their migration timing and routes, and location of the non-breeding sites. Between 2016 and 2021, we captured, banded, and deployed GPS archival tags on Southern Streaked Flycatchers, and conducted systematic monitoring of 61 individuals in rural and urban areas in southeastern Brazil. Our results revealed that this population migrates from the Atlantic Forest to Amazonia, spending 15-40 days on fall migration. Moreover, we found i) that overall return rates to breeding sites are high (>52%), ii) that return rates did not vary with sex, and iii) that return rates variedwith body condition and habitat, with birds in better condition having higher return rate in rural but not urban areas. More individual-level research on migratory birds in South American urban areas promises a novel perspective on how Neotropical austral migrants are responding to a rapidly changing landscape, and to inform future conservation initiatives in the increasingly expanding urban areas of southern Brazil. [ABSTRACT FROM AUTHOR]

The Yellow-rumped Flycatcher (Ficedula zanthopygia) is a secondary cavity nesting bird and widely distributed in China, Mongolia, Russia and Korea. In this study firstly sequenced the mitotic genome of the Yellow-rumped Flycatcher (Ficedula zanthopygia) gathered at Maorshan, China, using Illumina high-throughput sequencing technology, and then annotated the assembly. The total length of the complete mitochondrial genome is 16,730 bp and it consists of 13 protein-coding, 22 tRNA, 2 rRNA genes, and 1 control region (CR). The CR is 1148 bp in length. The nucleotide composition is 29.59% A, 14.75% T, 32.13% G, 23.54% C. The result of phylogenetic analysis showed that there is close genetic relationship among Ficedula zanthopygia and Ficedula hyperythra.

Acoustic signals mediate key animal interactions and can evolve through a variety of factors. Signal divergence can reinforce pre-zygotic barriers and minimize costly hybridizations among closely related species or partition acoustic space to avoid signal interference. To unravel the drivers of song evolution, it is critical to simultaneously test multiple evolutionary axes leading to heterospecific song variation (e.g., the role of morphology, ecology, and heterospecific recognition). Tyrannidae is the largest Passeriformes family and occurs across a broad environmental gradient. Tyrannids are suboscines, so song variation represents evolutionary differences that are not confounded by social learning. Several genera show conserved plumage coloration, but exhibit pronounced vocal differences. In the first of our two-part paper on signal ecology and evolution, we leveraged a large-scale song dataset to unravel song divergence in Tyrannidae (n = 282 species) by testing the relative influence of morphology (body and bill size), ecology (vegetation cover, diet, climate), and heterospecific proximity on song evolution. Based on phylogenetically controlled analyses, we found Tyrannidae song evolution was primarily driven by morphological adaptation, where larger-bodied birds with heftier bills sang lower frequency and slower paced songs. Pairwise song differences were weakly related to heterospecific proximity of some genera, lending support to the species recognition hypothesis or drift. Given that many flycatchers are habitat specialists, natural selection acting on bill morphology and body size in specific environmental-contexts may shape song among tyrannids. By simultaneously testing the relative roles of morphological, ecological, and geographical factors on song evolution, our study highlights the complexity of suboscine song evolution and the importance of large-scale comparative studies that test multiple evolutionary hypotheses.

Animal coloration is an important communication signal that varies among taxa and affects survival and reproduction. Species-specific color is influenced by a variety of factors including phylogeny, predation, sexual selection, light and resource availability, ecological context, and/or species recognition. Tyrant flycatchers are useful to study color evolution because they are the largest family of birds, occur across broad environmental gradients, and although many genera are monomorphic with drab plumage, some are very colorful. Given the complexity of factors involved, the mechanisms influencing plumage color evolution in Tyrant flycatchers likely involve multiple drivers. In the second of our two-part paper on signal evolution in this avian family, we harnessed a large plumage color database of female and male Tyrannidae species (n = 399) to test the relative importance of geography (climate, latitude), ecology (migration behavior, forest cover, diet), and heterospecific proximity on plumage color evolution. From phylogenetically controlled analyses, we found that female color was largely driven by climate and male color was more exaggerated in migratory species. Sexual dichromatism was also affected by climate and diet, and was more pronounced in migratory species, possibly as a result of color loss in females. Pairwise comparisons between heterospecific color differences and geographic distance were generally weak and consistent with expectations under drift, which contrasted our song results (presented in Part I), but analyses at finer taxonomic scales revealed color may be used for conspecific recognition in some genera. Together with our paper on Tyrannidae song evolution, the color results reflect the importance of testing multiple drivers of signal evolution at different taxonomic scales because flycatcher color variation may have arisen through genetic drift, from a loss of female color in migratory species, and for species recognition in some genera. Future work could formally test the correlation between song and color variation, and use stochastic character mapping to confirm if Tyrannidae dichromatism resulted from female color loss in migratory species.

Morphology is closely linked to locomotion and diet in animals. In animals that undertake long-distance migrations, limb morphology is under selection to maximize mobility and minimize energy expenditure. Migratory behaviours also interact with diet, such that migratory animals tend to be dietary generalists, whereas sedentary taxa tend to be dietary specialists. Despite a hypothesized link between migration status and morphology, phylogenetic comparative studies have yielded conflicting findings. We tested for evolutionary associations between migratory status and limb and bill morphology across kingbirds, a pan-American genus of birds with migratory, partially migratory and sedentary taxa. Migratory kingbirds had longer wings, in agreement with expectations that selection favours improved aerodynamics for long-distance migration. We also found an association between migratory status and bill shape, such that more migratory taxa had wider, deeper and shorter bills compared to sedentary taxa. However, there was no difference in intraspecific morphological variation among migrants, partial migrants and residents, suggesting that dietary specialization has evolved independently of migration strategy. The evolutionary links between migration, diet and morphology in kingbirds uncovered here further strengthen ecomorphological associations that underlie long-distance seasonal movements in animals. [ABSTRACT FROM AUTHOR]

Understanding how diet and life history strategies interact is important for exploring constraints of available nutrition on energetically expensive life history events in wild animals (i.e., reproduction, annual migration, molt). Previous research on migratory birds breeding in the Northern Hemisphere has demonstrated trophic niche shifts from invertebrates to fruit in order to fuel spring migration. We examined whether a trophic niche shift occurred in a Neotropical austral migrant, the Fork-tailed Flycatcher (Tyrannus savana savana), prior to spring migration by measuring stable nitrogen isotopes in feathers. We found that the austral migrant subspecies T. s. savana did appear to shift in diet from a higher to a lower trophic level (consistent in pattern with a shift from a higher to a lower ratio of invertebrates to fruit) but the shift occurred earlier than expected if it was preparation for migration. A sympatric sedentary subspecies occupying the same habitat (T. s. monachus) appeared to forage only at the lower trophic level during its annual molt and showed no evidence of a trophic niche shift; however, the molt of the 2 subspecies occurs at slightly different times of year. The timing of the trophic niche shift leads us to conclude that a higher trophic level diet early in molt is not related to preparation for spring migration but that it may be related to seasonal changes in food availability as the wet season concludes. A remaining challenge for understanding the ecological consequences of trophic niche shifts is to find ways to empirically measure trade-offs between different diets across energetically expensive life history events and compare these between taxa with differing life history strategies. [ABSTRACT FROM AUTHOR]

The Yellow-rumped Flycatcher (Ficedula zanthopygia) is a secondary cavity nesting bird and widely distributed in China, Mongolia, Russia and Korea. In this study firstly sequenced the mitotic genome of the Yellow-rumped Flycatcher (Ficedula zanthopygia) gathered at Maorshan, China, using Illumina high-throughput sequencing technology, and then annotated the assembly. The total length of the complete mitochondrial genome is 16,730 bp and it consists of 13 protein-coding, 22 tRNA, 2 rRNA genes, and 1 control region (CR). The CR is 1148 bp in length. The nucleotide composition is 29.59% A, 14.75% T, 32.13% G, 23.54% C. The result of phylogenetic analysis showed that there is close genetic relationship among Ficedula zanthopygia and Ficedula hyperythra. [ABSTRACT FROM AUTHOR]

During a patrolling duty in Jigme Singye Wangchuck National Park (JSWNP) in Bhutan, a lone male Blue-and-white Flycatcher Cyanoptila cyanomelan was observed and photographed. This is the first photographic evidence and confirmation on presence of the species in Bhutan. These new record confirm an extension of the species’ distribution in the North East Indian Sub Continent. As this is new record to Bhutan, there could be other undetected incidence of migrant species occurrence in the country. More observation must be carried out during bird migration seasons to discover such instances.

Food gathering strategies and their interactions contribute significantly to the knowledge of the ecological and evolutionary relationships of fauna. We report an observation of predatory behavior of Ochraceous Attila (Attila torridus) on the Buenaventura lizard (Anadia buenaventura), in the Buenaventura Reserve, El Oro province, Ecuador. On 12 November 2015, an adult of A. torridus was photographed carrying an adult A. buenaventura in its beak, after accommodating the lizard in its beak, the bird was lost in the vegetation, which was approximately 5 m in height. Although the consumption of its prey was not observed, it is assumed that it was devoured. The documentation of this event expands the knowledge of the natural history of this endemic species. [ABSTRACT FROM AUTHOR]

Taxa classified as subspecies may in fact be cryptic species. We assessed the taxonomic status of the Blue‐throated Flycatcher Cyornis rubeculoides complex in India, which consists of several forms with similar plumages and song. We used mitochondrial and nuclear DNA, plumage traits, and detailed song analysis to ascertain the taxonomic status of the different forms. The molecular data identified three primary clades: (1) in the west Himalayan foothills, (2) at higher elevations in the northeast hill states of Meghalaya, Nagaland and Mizoram, and (3) at lower elevations in the northeastern hills of Meghalaya and the east Himalayas of Arunachal Pradesh. The western clade represents nominate C. rubeculoides rubeculoides. The high‐elevation eastern clade was considered to be C. rubeculoides rogersi, because it included a sample from this subspecies from near the type locality in southwest Myanmar. These two sister clades had an estimated divergence time of 1.5 million years (my). The low‐elevation east clade has previously been assigned to C. rubeculoides, but we showed it is closely related to the Hainan Blue Flycatcher Cyornis hainanus, formerly thought to breed only further east, with an estimated divergence time of only ~0.8 my. This clade may represent a subspecies of C. hainanus or, given reports of widespread sympatry with C. hainanus in Thailand, a distinct species, Cyornis dialilaemus. However, more research is advocated, including molecular data, from the area of overlap. Songs were remarkably similar across all taxa. In playback experiments, C. r. rubeculoides in the west responded to all taxa. This is in agreement with recent work demonstrating that song differences and responses to songs are not always a good indicator of the progress of reproductive isolation. [ABSTRACT FROM AUTHOR]

Aggression is an important agonistic behavior in animals, with influence on the survival and reproductive success of the species. Flycatchers (Tyrannidae) exhibit highly visible social behaviors, but little has been documented on their agonistic behavior. We recorded an aggressive behavior of Hammond's Flycatcher (Empidonax hammondii) on Pine Toad (Incilius occidentalis) in a pine-oak forest of Omiltemi, Guerrero, Mexico. According to our observation and to what has been reported in the literature for other flycatchers, E. hammondii can present atypical behaviors related to the attack and/or predation of smallsized amphibians. [ABSTRACT FROM AUTHOR]

There is an increasing awareness that selection affecting linked neutral sites strongly influences on how diversity is distributed across the genome. In particular, linked selection is likely involved in the formation of heterogenous landscapes of genetic diversity, including genomic regions with locally reduced effective population sizes that manifest as dips in diversity, and “islands" of differentiation between closely related populations or species. Linked selection can be in the form of background selection or selective sweeps, and a long-standing quest in population genetics has been to unveil the relative importance of these processes. Here, we analyzed the theoretically expected reduction of diversity caused by linked selection in the collared flycatcher (Ficedula albicollis) genome and compared this with population genomic data on the distribution of diversity across the flycatcher genome. By incorporating data on recombination rate variation and the density of target sites for selection (including both protein-coding genes and conserved noncoding elements), we found that background selection can explain most of the observed baseline variation in genetic diversity. However, positive selection was necessary to explain the pronounced local diversity dips in the collared flycatcher genome. We confirmed our analytical findings by comprehensive simulations. Therefore, our study demonstrates that even though both background selection and selective sweeps contribute to the heterogeneous diversity landscape seen in this avian system, they play different roles in shaping it. [ABSTRACT FROM AUTHOR]

Bill deformities have been documented in many avian species across the globe and can be caused by environmental or genetic conditions that may also reflect ecosystem health. We describe the first case of bill deformity in the genus Tyrannus, in a young male Western Kingbird (Tyrannus verticalis) that fledged from a nest in an industrial park in Memphis, Tennessee, USA. The upper mandible of the bill was curved to the left and below the plane of the normal lower mandible making it unlikely that the individual would be able to forage normally and survive to adulthood. Genetic testing for evidence of hybridization with Scissor-tailed Flycatchers (T. forficatus) showed no sign of introgression, and it is unclear what caused the deformity. [ABSTRACT FROM AUTHOR]

Changes in habitat quality, including those caused by extreme events like droughts and floods, could alter costs and benefits of territoriality and thereby the prevalence and reproductive consequences for individuals capable of breeding that do not do so (floaters). We studied floating behavior in a population of Southwestern Willow Flycatchers (Empidonax traillii extimus) in central Arizona during one year of extreme drought, one year of lake inundation, and three years of near average precipitation. In all years, most floaters were second year (SY) males, and most subsequently settled outside of the patch where they were detected in the floating year, suggesting that floaters did not "queue" at high-quality territories in order to achieve higher reproductive success in subsequent years. Instead, cohorts that floated in non-drought years had lower apparent survival and lower reproductive success compared to territorial birds. In the extreme drought year, however, the number of floaters was 1.5 times greater than in all other years combined, more females floated, and apparent survival and mean annual productivity in subsequent years was higher for males that floated in that year than for those that were territorial. Inundation of habitat due to rising reservoir levels did not result in an increase in floaters because many birds nested in inundated areas where trees projected above the water so that the relative amount of available habitat was not reduced to the extent habitat models predicted. Overall, our results indicate that the prevalence and reproductive and demographic consequences of floating can change under extreme climatic events like severe drought. [ABSTRACT FROM AUTHOR]

The seasonal phenology of latitudinal movements is one of the key life-history traits of migratory birds. We used quantile regression to examine long-term changes in the timing of spring and autumn migration in 5 species of migratory passerine birds captured at a banding station in northern California, USA, over a 22 yr period from 1987 to 2008. Our 5 study species included 3 short-distance migrants, Pacific-slope Flycatcher [Empidonax difficilis), Orange-crowned Warbler [Oreothlypis celata), and Wilson's Warbler [Cardellina pusilla); and 2 long-distance migrants, Swainson's Thrush [Catharus ustulatus) and Yellow Warbler [Setophaga petechia). Median timing of migration advanced in spring for 2 of the 5 species (--2.5 days decade-1) but was delayed during autumn migration for 3 of the species (+2.9 days decade-1). The duration of the migration period also became compressed in some species but more protracted in others. We tested whether annual variation in migration timing was related to 3 indices of regional climatic conditions: the Pacific-North American index, multivariate El Niño-Southern Oscillation index, and North Atlantic Oscillation index. Climate indices explained relatively little of the variation in migration timing (r² < 0.35), but advances in spring migration and delays in autumn migration were associated with warm, wet conditions during positive phases of the climate indices. The strongest effects of climatic conditions on migration timing were found among short-distance migrants, with the largest changes in timing due to variation in the El Niño-Southern Oscillation and Pacific-North American indices. Linkages between the timing of movements and climatic conditions indicate that passerine birds on the Pacific coast exhibit phenotypic plasticity in their migration timing, but future studies based on experimental methods are needed to test alternative ecological mechanisms. [ABSTRACT FROM AUTHOR]

The seasonal phenology of latitudinal movements is one of the key life-history traits of migratory birds. We used quantile regression to examine long-term changes in the timing of spring and autumn migration in 5 species of migratory passerine birds captured at a banding station in northern California, USA, over a 22 yr period from 1987 to 2008. Our 5 study species included 3 short-distance migrants, Pacific-slope Flycatcher (Empidonax difficilis), Orangecrowned Warbler (Oreothlypis celata), and Wilson's Warbler (Cardellina pusilla); and 2 long-distance migrants, Swainson's Thrush (Catharus ustulatus) and Yellow Warbler (Setophaga petechia). Median timing of migration advanced in spring for 2 of the 5 species (-2.5 days decade-1) but was delayed during autumn migration for 3 of the species (þ2.9 days decade-1). The duration of the migration period also became compressed in some species but more protracted in others. We tested whether annual variation in migration timing was related to 3 indices of regional climatic conditions: the Pacific--North American index, multivariate El Niño--Southern Oscillation index, and North Atlantic Oscillation index. Climate indices explained relatively little of the variation in migration timing (r², 0.35), but advances in spring migration and delays in autumn migration were associated with warm, wet conditions during positive phases of the climate indices. The strongest effects of climatic conditions on migration timing were found among short-distance migrants, with the largest changes in timing due to variation in the El Niño--Southern Oscillation and Pacific--North American indices. Linkages between the timing of movements and climatic conditions indicate that passerine birds on the Pacific coast exhibit phenotypic plasticity in their migration timing, but future studies based on experimental methods are needed to test alternative ecological mechanisms. [ABSTRACT FROM AUTHOR]

Swallows are a unique group of songbirds because they are active-pursuit predators that execute all aspects of hunting prey in flight: search, detection, pursuit, and capture. We show that swallows have evolved a visual system that is unlike that of any other studied songbird. Swallows have a bifoveate retina that provides sharp lateral and frontal vision, an unusually long eye that enhances spatial resolution, a large posterior blind area, and a narrow binocular field. We also show that swallows and diurnal raptors (hawks and falcons) have converged on a similar visual configuration but that, interestingly, predatory songbirds that ambush prey (flycatchers) have not converged on the same suite of traits. Despite the commonly held belief that predators rely on binocular vision, the temporal (frontally projecting) fovea present in swallows—but not present in other songbirds—is likely not involved in binocular vision. Instead, swallows have four nonoverlapping foveae in a 1007 arc around the beak, which can improve the tracking of frontally located aerial prey that are engaging in evasive maneuvers. Overall, vision in pursuit predators reflects the complex sensory demands of hunting in the air at high speeds and emphasizes the importance of acute frontal vision in predators. [ABSTRACT FROM AUTHOR]

Nest predation is one of the most important mortality factors of birds. Field observations showed that tits (Paridae) produce hissing calls and, usually, have lower breeding losses than nesting Ficedula flycatchers, which do not make such calls. We hypothesise that differences in fledgling success can be directly attributed to the vocal reaction of tits. We tested experimentally whether the hissing calls can affect the behaviour of a potential predator, analysing the response of the Yellow-necked Mouse Apodemus flavicollis to playback of calls of three Parid species. The number of visits by mice to two types of cavities (with playback and control) was not significantly different, but the average time spent by mice in cavities with playback (3.9 s) was significantly shorter than in cavities without playback (26.3 s). This suggests that hissing behaviour of tits significantly changes the exploration activity of predators, which may ultimately increase the breeding success of this group of birds relative to the flycatchers. Significance statement: Nest predation is one of the most important mortality factors of small land birds, but some anti-predatory mechanisms are still poorly recognised. Numerous studies demonstrate that incubating tits make hissing sounds, when a predator is near, but despite almost a century of research, there is little evidence these calls indeed affect behaviour of predators. By using a simple laboratory experiment, we demonstrated that the hissing acoustic signals used by tits may change the behaviour of yellow-necked mice, which are an important predator of cavity-nesting birds in temperate forests. Intruding mice withdrew from cavities where hissing sounds were played back. Our results suggest that the hissing behaviour of tits can change the exploration activity of potential predators and may increase breeding success of this group of birds relative to the flycatchers, which stay silent when their nest is threatened. [ABSTRACT FROM AUTHOR]

Predator presence and shortage of food resources can alter behavior and cause chronic physiological stress, with long-term detrimental effects on the prey. Recently, it has been hypothesized that cellular damage via oxidative stress could be associated with such effects. Variation in food availability and predation risk could modify the oxidative/antioxidant status of prey. However, data from wild populations is scarce and, importantly, the interactive effects of these major ecological factors on oxidative/antioxidant status are poorly understood. We present the first study in a wild vertebrate, addressing the combined effects of experimental food supplementation and increased predation risk (cues of Mustela erminea) on antioxidant status of female pied flycatchers ( Ficedula hypoleuca). We tested the effects during breeding, assuming that such variation could modify the antioxidant cost of reproduction. Supplementary food increased female body mass, independently of predator treatment. However, timing of breeding and reproductive investment remained unaffected by the treatments. Principal component 1 (PC 1) of antioxidant levels [reflecting superoxidase dismutase (SOD), glutathione peroxidase (GPx), and glutathione (tGSH)] showed lower values in the food-supplemented than non-food-supplemented group. Neither PC 2 [reflecting catalase (CAT) and GSH/GSSG ratio] nor PC 1 was affected by predation risk, and further, predation risk did not alter the effect of supplementary food on either PC. These results suggest that food resources may have a stronger impact than predation risk on female antioxidant status during breeding. This is the first fully experimental study focusing on the interactive effects of key environmental variables on antioxidant status in wild vertebrates; more studies are however needed to understand the role of these factors in shaping the cost of reproduction. Significance statement: Predator presence and shortage of food resources may modify animal behavior and cause chronic physiological stress response with long-term detrimental effects on the prey. Recently, it has been hypothesized that cellular damage via oxidative stress (i.e., imbalance between pro-oxidants and antioxidant defenses) could be associated with such effects, but evidence from wild populations is scarce. Importantly, the interactive effects of food and predation are not well understood. For the first time in a vertebrate, we experimentally studied the combined effects of food availability and (simulated) predation risk on antioxidant status, using wild breeding passerines. Higher food availability, but not increased perceived predation risk, lowered the antioxidant defenses. Predation risk did not alter the effect of supplementary food. The role of such interactions in shaping the cost of reproduction (via antioxidant/oxidative status) should be further studied. [ABSTRACT FROM AUTHOR]

The breeding biology of approximately one third of all Fluvicolinae species is largely unknown and little is known about Streamer-tailed Tyrant ( Gubernetes yetapa). Despite being locally fairly common, only a brief description of its nest has been published. For the species, Chubb (1910) described gonadal state, nest building, and young seen, but no additional details have been published. Here, we describe the nest and eggs of Streamer-tailed Tyrant from Brazil and Paraguay and review nesting activity based on fledgling records from Brazil. The nest was an open cup in the center of a clump of Saccharum sp. grass within a marshy area. The outer portion was lined with thick grass stems. The inner portion of the cup was lined with fine roots, grass stems, and shed snake skins (Colubridae and Viperidae). The nest contained three totally white and oval shaped eggs. Egg mass ranged from 6.84-9.02 g. The period of nesting activity apparently lasted at least from October through January, similar to several other Fluvicolinae species from southeastern Brazil. [ABSTRACT FROM AUTHOR]

In some avian species, individuals spend most of their lives in complex social groups. A recent hypothesis argues that social complexity will drive complexity in signaling systems. According to this hypothesis, individuals living in more complex groups (larger and with greater diversity of interactions) require larger and more diverse repertoires of signals, compared to individuals living in groups that are relatively simple in social structure. Social complexity has also been argued to be an important driver of social cognition and cooperation. Although many of these arguments have been based on empirical findings with non-human primates, similar evidence is beginning to emerge from avian studies. Here, we discuss some of this avian evidence, with an emphasis on two model species: Carolina chickadees, Poecile carolinensis (Paridae), and pied flycatchers, Ficedula hypoleuca. In Carolina chickadees, variation in the structure of chick- a- dee calls influences behavior of receivers in pro-social and potentially cooperative ways in anti-predator and food detection contexts. In pied flycatchers, breeding individuals were much less likely to travel greater distances to assist in mobbing predators near their conspecific neighbors if those neighbors had failed to assist them in mobbing earlier. More research is needed to determine whether communicative complexity per se makes sophisticated social cognition possible, such as reconciliation and cooperation (and whether the latter might stem from reciprocal altruism or less cognitively demanding processes like conspecific by-product mutualism). [ABSTRACT FROM AUTHOR]

As urbanization transforms landscapes around the globe, we are challenged to find ways for urban habitats to contribute to ongoing wildlife conservation efforts. Yet aside from basic distributions and relative abundance, we know little about the population dynamics of most species occupying urban habitats and almost nothing about the extent to which local populations serve as source or sink habitats. We analyzed the spatial synchrony and persistence of local populations of 16 avian species breeding in 14 mature riparian forests in central Ohio, USA during 2005-2011. In addition, we examined demographic growth rates (λ) for 2 focal species (northern cardinal, Cardinalis cardinalis, and Acadian flycatcher, Empidonax virescens) to understand source-sink structure. Our results showed high rates of population turnover for the majority of species and negative growth rates for both focal species, indicating that most populations functioned as sinks. Local populations showed little evidence of population synchrony, as we found consistently low or negative spatial autocorrelation and relatively high rates of population turnover for both migratory and resident species. Collectively our results suggest that long-term persistence of regional populations of birds breeding in Midwestern riparian forest fragments may be facilitated by metapopulation dynamics. [ABSTRACT FROM AUTHOR]

The avian genus Ficedula has been a model system for studying speciation, genomics, biogeography, and the evolution of migratory behavior. However, no multi-locus molecular phylogenetic hypothesis exists for the genus. We expanded taxon and character sampling over previous studies and produced a robust hypothesis of relationships for the genus. Many previous findings, such as the inclusion of Muscicapella and exclusion of Ficedula monileger from the genus, were verified, but many relationships differed compared to previous work. Some of the differences were due to increased sampling, but others were due to problematic sequence data produced from DNA extracted from historical museum specimens. The new phylogenetic hypothesis resulted in a simpler biogeographic scenario with fewer transitions between regions and fewer transitions between seasonally migratory and resident character states. Notably, all species endemic to the Philippines and Wallacea formed a clade, which included Ficedula dumetoria of the Sunda Shelf and Lesser Sundas. In addition, Ficedula hyperythra was not monophyletic; samples from Philippine populations formed a clade distantly related to a clade that comprised all other sampled populations. [ABSTRACT FROM AUTHOR]

We studied the diet of nestling Spectacled Tyrants ( Hymenops perspicillatus) in the southeast Pampas region, Argentina. From November 2012 to January 2013, we used video footage to determine prey items that the parents fed to their chicks. We obtained 54 hrs of recording time to survey 18 nests. We identified a total of 125 prey items, representing 33 different taxa, grouped into four classes: Insecta, Arachnida, Chilopoda, and Amphibia. Insects accounted for 94% of total prey. The most frequent prey items were orthopterans (Caelifera), unidentified lepidopteran larvae, and odonats (Zygoptera). Lepidopterans were numerically the most important prey item in November, odonats in December, and orthopterans in January. Diet of the nestling birds was generalist in terms of the consumption of insects, and the changes in prey consumption during the course of the breeding season support an opportunistic feeding behavior by Spectacled Tyrants. [ABSTRACT FROM AUTHOR]