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Molt strategies have received relatively little attention in current ornithology, and knowledge concerning the evolution, variability and extent of molt is sparse in many bird species. This is especially true for East Asian Locustella species where assumptions on molt patterns are based on incomplete information. We provide evidence indicating a complex postbreeding molt strategy and variable molt extent among the Pallas's Grasshopper Warbler Locustella certhiola, based on data from six ringing sites situated along its flyway from the breeding grounds to the wintering areas. Detailed study revealed for the first time that in most individuals wing feather molt proceeds from the center both toward the body and the wing-tip, a molt pattern known as divergent molt (which is rare among Palearctic passerines). In the Russian Far East, where both breeding birds and passage migrants occur, a third of the adult birds were molting in late summer. In Central Siberia, at the northwestern limit of its distribution, adult individuals commenced their primary molt partly divergently and partly with unknown sequence. During migration in Mongolia, only descendantly (i.e., from the body toward the wing-tip) molting birds were observed, while further south in Korea, Hong Kong, and Thailand the proportion of potential eccentric and divergent feather renewal was not identifiable since the renewed feathers were already fully grown as expected. We found an increase in the mean number of molted primaries during the progress of the autumn migration. Moderate body mass levels and low-fat and muscle scores were observed in molting adult birds, without any remarkable increase in the later season. According to optimality models, we suggest that an extremely short season of high food abundance in tall grass habitats and a largely overland route allow autumn migration with low fuel loads combined with molt migration in at least a part of the population. This study highlights the importance of further studying molt strategy as well as stopover behavior decisions and the trade-offs among migratory birds that are now facing a panoply of anthropogenic threats along their flyways., Finanziert über die DEAL-Vereinbarung mit Wiley 2019-2022.

The selection of a nest site is crucial for successful reproduction of birds. Animals which re-use or occupy nest sites constructed by other species often have limited choice. Little is known about the criteria of nest-stealing species to choose suitable nesting sites and habitats. Here, we analyze breeding-site selection of an obligatory “nest-cleptoparasite”, the Amur Falcon 'Falco amurensis'. We collected data on nest sites at Muraviovka Park in the Russian Far East, where the species breeds exclusively in nests of the Eurasian Magpie 'Pica pica'. We sampled 117 Eurasian Magpie nests, 38 of which were occupied by Amur Falcons. Nest-specific variables were assessed, and a recently developed habitat classification map was used to derive landscape metrics. We found that Amur Falcons chose a wide range of nesting sites, but significantly preferred nests with a domed roof. Breeding pairs of Eurasian Hobby 'Falco subbuteo' and Eurasian Magpie were often found to breed near the nest in about the same distance as neighboring Amur Falcon pairs. Additionally, the occurrence of the species was positively associated with bare soil cover, forest cover, and shrub patches within their home range and negatively with the distance to wetlands. Areas of wetlands and fallow land might be used for foraging since Amur Falcons mostly depend on an insect diet. Additionally, we found that rarely burned habitats were preferred. Overall, the effect of landscape variables on the choice of actual nest sites appeared to be rather small. We used different classification methods to predict the probability of occurrence, of which the 'Random forest' method showed the highest accuracy. The areas determined as suitable habitat showed a high concordance with the actual nest locations. We conclude that Amur Falcons prefer to occupy newly built (domed) nests to ensure high nest quality, as well as nests surrounded by available feeding habitats., Finanziert über die DEAL-Vereinbarung mit Wiley 2019-2022.

The selection of a nest site is crucial for successful reproduction of birds. Animals which re‐use or occupy nest sites constructed by other species often have limited choice. Little is known about the criteria of nest‐stealing species to choose suitable nesting sites and habitats. Here, we analyze breeding‐site selection of an obligatory “nest‐cleptoparasite”, the Amur Falcon Falco amurensis. We collected data on nest sites at Muraviovka Park in the Russian Far East, where the species breeds exclusively in nests of the Eurasian Magpie Pica pica. We sampled 117 Eurasian Magpie nests, 38 of which were occupied by Amur Falcons. Nest‐specific variables were assessed, and a recently developed habitat classification map was used to derive landscape metrics. We found that Amur Falcons chose a wide range of nesting sites, but significantly preferred nests with a domed roof. Breeding pairs of Eurasian Hobby Falco subbuteo and Eurasian Magpie were often found to breed near the nest in about the same distance as neighboring Amur Falcon pairs. Additionally, the occurrence of the species was positively associated with bare soil cover, forest cover, and shrub patches within their home range and negatively with the distance to wetlands. Areas of wetlands and fallow land might be used for foraging since Amur Falcons mostly depend on an insect diet. Additionally, we found that rarely burned habitats were preferred. Overall, the effect of landscape variables on the choice of actual nest sites appeared to be rather small. We used different classification methods to predict the probability of occurrence, of which the Random forest method showed the highest accuracy. The areas determined as suitable habitat showed a high concordance with the actual nest locations. We conclude that Amur Falcons prefer to occupy newly built (domed) nests to ensure high nest quality, as well as nests surrounded by available feeding habitats., We analyzed the breeding‐site selection of an obligatory nest‐cleptoparasite, the Amur Falcon (Falco amurensis). Based on nest site characteristics sampled in the field and a digital habitat map we demonstrate that Amur Falcons select specifically nests newly built by Magpies (Pica pica) which are surrounded by favourable feeding habitat.

The population of the Yellow-breasted Bunting 'Emberiza aureola', a formerly widely distributed and abundant songbird of northern Eurasia, suffered a catastrophic decline and a strong range contraction between 1980 and 2013. There is evidence that the decline was driven by illegal trapping during migration, but potential contributions of other factors to the decline, such as land-use change, have not yet been evaluated. Before the effects of land-use change can be evaluated, a basic understanding of the ecological requirements of the species is needed. We therefore compared habitat use in ten remaining breeding regions across the range, from European Russia to Japan and the Russian Far East. We also assessed large-scale variation in habitat parameters across the breeding range. We found large variation in habitat use, within and between populations. Differences were related to the cover and height of trees and shrubs at Yellow-breasted Bunting territories. In many regions, Yellow-breasted Buntings occupied early successional stages, including anthropogenic habitats characterized by mowing, grazing, or fire regimes. We found that the probability of presence can be best predicted with the cover of shrubs, herbs, and grasses. Highest probabilities were found at shrub cover values of 40%–70%. Differences in habitat use along a longitudinal gradient were small, but we found strong differences across latitudes, possibly related to habitat availability. We conclude that the remaining Yellow-breasted Bunting populations are not limited to specific habitat types. Our results provide important baseline information to model the range-wide distribution of this critically endangered species and to guide targeted conservation measures., Finanziert über die DEAL-Vereinbarung mit Wiley 2019-2022