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In recent decades, several explanations for vagrancy of North Asian bird species in Europe have been suggested. The explanations can typically be divided into two, non‐exclusive groups. Some cite weather factors as the primary cause of vagrancy, whereas others hypothesize an internal defect behind the phenomenon. In addition, some authors also suggest climate‐driven range expansion following breeding population increase as a contributing factor. In recent years, studies have been published that have provided clear evidence for the origin of vagrant birds, as well as the reasons for their vagrancy. Here we summarize current knowledge and conclude that weather, habitat use, feeding habit, breeding success and climate change are important factors that affect the vagrancy of birds, together with the number of observers playing an important role in contributing data. In the future, advances in technology such as the development of tracking systems and the extensive use of stable isotopes will make it possible to explain the causes of vagrancy more precisely, so further research in this area of ornithology is essential. [ABSTRACT FROM AUTHOR]

The timing of annual events in migratory species is determined by the position of breeding and wintering grounds, length of the breeding season, the occurrence of their preferred diet or the timing of moult in birds. Previous studies found significant differences in the migration phenology of Asian Phylloscopus warbler species, a group of long-distance migratory passerines. However, the factors that influence the observed differences in migration phenology have not been studied yet. Here, we analyze the effect of the above-mentioned factors on the migration timing of seven Phylloscopus species at a stopover site in the Russian Far East. We found that spring migration phenology was best explained by moult strategy and the preferred prey size, while autumn migration phenology was linked to the southernmost wintering latitude of the species. Interspecific differences in migration timing were much higher in autumn than in spring. The duration of the species-specific migration periods was also longer in autumn than in spring, most likely caused by higher competition during spring to arrive early at the breeding grounds. Our results contribute to the understanding of migration ecology in songbirds moving along the little-studied East Asian flyway. [ABSTRACT FROM AUTHOR]

Birds are hosts for several zoonotic pathogens. Because of their high mobility, especially of longdistance migrants, birds can disperse these pathogens, affecting their distribution and phylogeography. We focused on Borrelia burgdorferi sensu lato, which includes the causative agents of Lyme borreliosis, as an example for tick‐borne pathogens, to address the role of birds as propagation hosts of zoonotic agents at a large geographical scale. We collected ticks from passerine birds in 11 European countries. B. burgdorferi s.l. prevalence in Ixodes spp. was 37% and increased with latitude. The fieldfare Turdus pilaris and the blackbird T. merula carried ticks with the highest Borrelia prevalence (92 and 58%, respectively), whereas robin Erithacus rubecula ticks were the least infected (3.8%). Borrelia garinii was the most prevalent genospecies (61%), followed by B. valaisiana (24%), B. afzelii (9%), B. turdi (5%) and B. lusitaniae (0.5%). A novel Borrelia genospecies "Candidatus Borrelia aligera" was also detected. Multilocus sequence typing (MLST) analysis of B. garinii isolates together with the global collection of B. garinii genotypes obtained from the BorreliaMLST public database revealed that: (a) there was little overlap among genotypes from different continents, (b) there was no geographical structuring within Europe, and (c) there was no evident association pattern detectable among B. garinii genotypes from ticks feeding on birds, questing ticks or human isolates. These findings strengthen the hypothesis that the population structure and evolutionary biology of tick‐borne pathogens are shaped by their host associations and the movement patterns of these hosts. [ABSTRACT FROM AUTHOR]

Bird species following a loop migration strategy use different routes during autumn than in the spring season. Birds nesting at different latitudes have different wing morphology. Finding significant differences in the average wing lengths of the same species between the autumn and spring seasons in the same area suggests loop migration. If these differences are also different by sex, this suggests that males and females do not use the same migratory routes. In this study, we analysed wing morphological differences of seven common long-distance migrant passerine species ringed at the Ócsa Bird Ringing Station from 1984 to 2014. Species were divided into three groups based on moult strategies (pre-, postnuptial and double moult). Based on differences in wing length distributions and means between autumn and spring, six of the seven passerine species follow loop migration. While wing length differences can be adequate to detect loop migration, the species specific moult strategies, the nesting sites and distribution ranges need to be known. [ABSTRACT FROM AUTHOR]

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Barn swallows Hirundo rustica often have characteristic feather holes on wing and tail feathers. During the past 15 yr, several influential papers have been based on the assumption that these holes were chewed by the louse Machaerilaemus malleus. We gathered feather-hole data from barn swallows and other passerines at 2 sites in Hungary and correlated the presence of holes with louse infestations and, more specifically, with the occurrence of M. malleus versus other species of avian lice. The shape of frequency distribution of holes was left-biased, and this bias was more pronounced in large swallow colonies that in a random sample, in accordance with the view that the causative agent of the 'feather hole symptom' is a contagious macroparasite. However, both intra- and interspecific comparisons suggest that the causative agent of the symptom had probably been misidentified. The occurrence of Brueelia spp. 'wing lice' provides the best fit to the distribution and abundance of feather holes, both in barn swallows and across some other small passerines. This identification error does not challenge the results of the former evolutionary-ecological studies based on this model system, although it has important implications from the viewpoint of louse biology. [ABSTRACT FROM AUTHOR]

Ecdysteroids (arthropod molting hormones) play an important role in the development and sexual maturation of arthropods, and they have been shown to have anabolic and "energizing" effect in higher vertebrates. The aim of this study was to assess ecdysteroid diversity, levels according to bird species and months, as well as to observe the molting status of hard ticks (Acari: Ixodidae) infesting the birds. Therefore, blood samples and ticks were collected from 245 birds (244 songbirds and a quail). Mass spectrometric analyses showed that 15 ecdysteroids were regularly present in the blood samples. Molting hormones biologically most active in insects (including 20-hydroxyecdysone [20E], 2deoxy-20E, ajugasterone C and dacryhainansterone) reached different levels of concentration according to bird species and season. Similarly to ecdysteroids, the seasonal presence of affected, apolytic ticks peaked in July and August. In conclusion, this study demonstrates the presence of a broad range and high concentrations of ecdysteroids in the blood stream of wild-living passerine birds. These biologically active, anabolic compounds might possibly contribute to the known high metabolic rate of songbirds. [ABSTRACT FROM AUTHOR]

Background: Weather effects on bird migration are well-studied among Passerines moving from Europe to Africa or within the American flyway systems. However, little is known about the weather impact on songbirds migrating along the East Asian flyway. Our study aims to describe the effects of various weather elements on the migration of four species of leaf warblers by using bird ringing data from a stopover site in Far East Russia. Methods: We determined the migration periods for each species and included maximum temperature, precipitation, air pressure, wind speed and wind direction in general linearized mixed models to predict the number of migrating birds. Results: We found strong impacts of weather variables on the number of trapped warblers during spring and autumn migration. Preferred or avoided weather conditions were similar among the studied species. All species seem to migrate preferably during warm, calm days without precipitation. A positive effect of tail winds was only confirmed in autumn, but in spring, most birds were trapped during crosswinds (eastern or western winds). Conclusion: The studied species might exhibit a loop migration, leading to a more longitudinal (from east to west) migration pattern in our study area during spring. Relationships between weather variables and the number of migrating individuals were much stronger during autumn. We argue that birds during spring migration would continue migration under sub-optimal conditions, as a result of strong competition to arrive earliest on their breeding grounds. [ABSTRACT FROM AUTHOR]