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Structural variation (SV) constitutes an important type of genetic mutations providing the raw material for evolution. Here, we uncover the genome-wide spectrum of intra- and interspecific SV segregating in natural populations of seven songbird species in the genus Corvus . Combining short-read ( N  = 127) and long-read re-sequencing ( N  = 31), as well as optical mapping ( N  = 16), we apply both assembly- and read mapping approaches to detect SV and characterize a total of 220,452 insertions, deletions and inversions. We exploit sampling across wide phylogenetic timescales to validate SV genotypes and assess the contribution of SV to evolutionary processes in an avian model of incipient speciation. We reveal an evolutionary young (~530,000 years) cis -acting 2.25-kb LTR retrotransposon insertion reducing expression of the NDP gene with consequences for premating isolation. Our results attest to the wealth and evolutionary significance of SV segregating in natural populations and highlight the need for reliable SV genotyping. Structural genomic variation can fuel evolution. Here, authors present genome data from seven Corvus species and unearth structural variants that vary between incipient crow species in Europe, with implications for premating isolation involving plumage patterning.

The frequency and extent of fires are increasing worldwide. Fires impact biodiversity, including bird communities. However, our knowledge is biased towards breeding bird communities, with fire impacts on birds during migration being poorly studied. Migratory birds rely on suitable stopover sites, and any changes at such sites could negatively affect their survival and population dynamics. We investigated the effects of an anthropogenic fire on birds captured at an autumn stopover site, comparing data from one year with fire to four years thereafter without. We found significant negative effects of fire on bird abundance and diversity, though species composition remained largely unchanged. We posit that reduced habitat and food availability after fire cause these effects. We also assessed variation in stopover duration and fuel deposition rate in two species, but found no overall significant fire-related effects in either case. Management strategies should aim at limiting the extent of fires to sustain suitable stopover habitat patches.

Sex- and age-specific differences in the timing of migration are widespread among animals. In birds, common patterns are protandry, the earlier arrival of males in spring, and age-differential migration during autumn. However, knowledge of these differences stems mainly from the Palearctic-African and Nearctic-Neotropical flyways, while detailed information about the phenology of migrant birds from the East Asian flyway is far scarcer. To help fill parts of this gap, we analyzed how migration distance, sex, age, and molt strategy affect the spring and autumn phenologies of 36 migrant songbirds (altogether 18,427 individuals) at a stopover site in the Russian Far East. Sex-differential migration was more pronounced in spring than in autumn, with half of the studied species (6 out of 12) showing a protandrous migration pattern. Age-differences in migration were rare in spring but found in nearly half of the studied species (11 out of 25) in autumn. These age effects were associated with the birds’ molt strategy and the mean latitudinal distances from the assumed breeding area to the study site. Adults performing a complete molt before the onset of autumn migration passed the study site later than first-year birds undergoing only a partial molt. This pattern, however, reversed with increasing migration distance to the study site. These sex-, age-, and molt-specific migration patterns agree with those found along other flyways and seem to be common features of land bird migration strategies.

Lunar cycle and moonlight exposure have significant impacts on animal behaviour and physiology. The presence or absence of moonlight, along with predictable changes in brightness throughout the lunar cycle, can shape reproduction, foraging, communication, and other aspects of an animal’s world. While it has been shown that invertebrates use the moonlight for orientation, little is known on the effect of the lunar cycle on migratory birds. We found that the lunar cycle affected the nocturnal migration activity of a diurnal songbird species, the Eurasian Skylark Alauda arvensis. The occurrence of birds increased with moon fraction, moonlight intensity and duration, while abundance correlated positively with increasing moonlight intensity. Our findings of increased migration activity in bright nights around full moon contradict previous assumptions that small bird migrants would avoid such nights due to increased predation pressure and decreased visibility of stars for orientation. We argue that migrants relying on visual cues for orientation might favour moonlit nights, while future studies should also test whether the position of the moon can be used for navigation by birds.

Migratory animals rely on multiple sites during their annual cycles. Deteriorating conditions at any site can have population-level consequences, with long-distance migrants seen as especially susceptible to such changes. Reduced adult survival caused by persecution at non-breeding sites has been suggested a major reason for the catastrophic decline of a formerly abundant, long-distance migratory songbird, the Yellow-breasted Bunting Emberiza aureola . However, it is unknown whether the ongoing extinction of this Eurasian species especially in the west of its range could be related to differences in survival or migration routes. We investigated survival rates of populations from both western and eastern parts of the breeding range and successfully tracked the migration of individuals from two eastern populations with light-level geolocators. We found moderate apparent local survival rates in eastern populations, but observed no returning birds in western populations. Our tracking data highlights (1) a joint migration corridor of eastern populations through eastern China, (2) long autumn stopovers likely used for moult and re-fuelling, and (3) very long occurrences at wintering sites. These areas should be given priority for future conservation measures. We call for an increased monitoring of adult survival and breeding output in multiple populations (including western ones) of this critically endangered species to determine (1) the causes for the observed differences in apparent local survival and (2) whether the current survival rates are sufficient to sustain viable breeding populations.

Artificial nest sites can support populations of endangered species when they are correctly installed. Here we analysed the characteristics and conditions that determined whether the northern house martin Delichon urbicum occupied more than 300 artificial nests around the city of Münster, Germany. We found that artificial nest occupation rates were influenced by various environmental and temporal factors. Positive influences included a longer time since installation and, to a lesser extent, the number of artificial nests at the same site. Negative impacts were observed from higher proportions of sealed surface cover in the surrounding area and, to a lesser extent, southward exposure. The distance to the nearest water body and the number of occupied natural nests showed no significant effect. We compared our results with descriptive evidence from the grey literature and published reports, and we give recommendations for installing artificial house martin nests for conservation practitioners. Future studies should also investigate the potential negative effects of ‘dirt boards’ below the nests and of gaps between the roof and the artificial nests. Artificial nest sites can support populations of endangered species when they are correctly installed. We found that occupation rates of artificial House Martin nests were lower for nests with a higher proportion of sealed surface cover in the surrounding area but were positively affected by increasing time since installation and the number of artificial nests at the same site. We summarise the range‐wide evidence and compare it with our data to give the best possible recommendations for conservation practitioners on how to install artificial nests for this declining bird species.

Basic information on the ecology of species is key for their conservation. Here we study the ecology of the little‐known yellow‐throated bunting Emberiza elegans based on a multi‐year study on its breeding grounds in the Russian Far East. For the first time in this species, we quantified breeding habitat parameters, calculated sex‐specific apparent survival, and determined individual nonbreeding locations using light‐level geolocation. We found that the habitat around song posts of male yellow‐throated buntings is characterized by tree and shrub layers on richly littered moist ground. Habitat use overlaps with co‐occurring Tristram's Buntings Emberiza tristrami and Black‐faced Buntings E. spodocephala, but territories differ especially in tree cover and litter cover. Based on 4 years of color‐ringing data of 72 individuals, we calculated an apparent survival rate of 36%, with higher survival estimates for male than for female yellow‐throated buntings. We found no effect of carrying a geolocator on survival. We retrieved six geolocators from males. All birds migrated south‐westward during autumn and spent the nonbreeding season at locations in China 700–1700 km away from their breeding sites. At least two individuals spent the boreal winter outside of the known range in northern or central China. Birds left the breeding area between early October and early November and returned between mid‐March and mid‐April. Our data on habitat use, survival rate, and migratory connectivity will help to assess threats to the populations of this enigmatic species, which might include habitat loss due to forest fires on the breeding grounds, and unsustainable harvest for consumption during the nonbreeding season. Basic information on the ecology of species is crucial for conservation. Here we provide data on breeding habitat use, survival rates, and spatiotemporal distribution for the little‐studied yellow‐throated bunting. We found that individuals breeding in the Russian Far East migrate to China during the boreal winter.

Migration strategies are genetically inherited in most songbirds, and closely related species can exhibit markedly contrasting migration programs. Here, we investigate the autumn migration of one Helopsaltes grasshopper‐warbler from a population near Magadan, North East Russia, based on light‐level geolocation. Although often considered to belong to Middendorff's Grasshopper‐warbler H. ochotensis, recent genetic studies suggest that birds from this population are more closely related to Pallas's Grasshopper‐warbler H. certhiola. We compare the migratory behavior of the Magadan bird with two Pallas's Grasshopper‐warblers tracked from populations in the Kolyma River valley and the Amur region, Russia. We found similar migration patterns in all three tracked individuals, with stopover sites in eastern China and wintering sites in mainland Southeast Asia, within the known range for Pallas's Grasshopper‐warbler. Furthermore, based on morphological data compiled during bird ringing, we were able to confirm the presence of potential “Magadan grasshopper‐warblers” during spring and autumn migration in Thailand. Our scant data provide further evidence that Magadan Helopsaltes, notwithstanding their morphological resemblance to Middendorff's Grasshopper‐warbler, constitute a population of Pallas's Grasshopper‐warbler. Here, we investigate the autumn migration of Helopsaltes grasshopper‐warblers from North‐East Russia based on light‐level geolocation. We found that individuals from the Magadan population showed similar migration patterns to Pallas's Grasshopper‐warblers, with stopover sites in eastern China and stationary sites during the boreal winter in Southeast Asia. Although limited to single individuals, our data provide further evidence that grasshopper‐warblers from Magadan should be included into Pallas's Grasshopper‐warbler and should not be treated as a subspecies of Middendorff's Grasshopper‐warbler.

The dramatic decline in the once superabundant Yellow‐breasted Bunting Emberiza aureola, a widely distributed Eurasian songbird, triggered worldwide media interest. Five years after the initial publication, we set out to give an update on the status of this critically endangered species, the conservation actions that followed, and the lessons that can be learned from this exceptional case for the conservation of migratory land birds in Asia and beyond. While there are signs of possible population recovery in the Yellow‐breasted Bunting, other migratory songbird species were recently observed to be trapped in huge numbers, which could lead to further declines. We argue that the Yellow‐breasted Bunting can be used as a flagship species to promote the conservation of East Asian land bird migrants.