Long-distance migratory birds often face major geographical barriers on their journey.While some species are able to cross them,others use longer routes to avoid such barriers.Little is known about the strategies of S...Long-distance migratory birds often face major geographical barriers on their journey.While some species are able to cross them,others use longer routes to avoid such barriers.Little is known about the strategies of Siberian landbird migrants,which either cross or circumvent the deserts and mountain ranges of Central Asia en route to their non-breeding sites in Southeast Asia.Here we compare data on migration phenology and morphology from two bird ringing stations in eastern Russia,situated at similar latitudes but with a longitudinal difference of 1500 km,to hypothesise migration patterns.We found significant differences in timing between the two sites(birds migrated significantly earlier in spring and significantly later in autumn in the east),suggesting longitudinal migration as a result of migration detour.However,morphological differences show a less clear pattern.We argue that most Siberian landbirds might opt for a detour through the Russian Far East instead of a direct route in order to avoid unfavourable stop-over habitat in Central Asia.However,tracking studies will be necessary to prove this.展开更多
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 migrat...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.展开更多
Stopover niche utilization of birds during migration has not gained much attention so far,since the majority of the studies focuses on breeding or wintering areas.However,stopover sites are crucial for migratory birds...Stopover niche utilization of birds during migration has not gained much attention so far,since the majority of the studies focuses on breeding or wintering areas.However,stopover sites are crucial for migratory birds.They are often used by a multitude of species,which could lead to increased competition.In this work,we investigated niche use of 8 migratory and closely related Emberiza bunting species at a stopover site in Far East Russia,situated on the poorly studied East Asian flyway.We used bird ringing data to evaluate morphological similarity as well as niche overlap on the trophic,spatial,and temporal dimension.Bill morphology was used as a proxy for their trophic niche.We were able to prove that a majority of the species occupies well-defined stopover niches on at least one of the dimensions.Niche breadth and niche overlap differ between spring and autumn season with higher overlap found during spring.Morphological differences are mostly related to overall size and wing pointedness.The temporal dimension is most important for segregation among the studied species.Furthermore,all species seem to exhibit a rather strict and consistent phenological pattern.Their occurrence at the study site is highly correlated with their geographic origin and the length of their migration route.We assume that buntings are able to use available resources opportunistically during stopover,while trying to follow a precise schedule in order to avoid competition and to ensure individual fitness.展开更多
基金Funding supply on Baikal Bird Ringing Station was conducted by Baikalsky State Nature Reserve。
文摘Long-distance migratory birds often face major geographical barriers on their journey.While some species are able to cross them,others use longer routes to avoid such barriers.Little is known about the strategies of Siberian landbird migrants,which either cross or circumvent the deserts and mountain ranges of Central Asia en route to their non-breeding sites in Southeast Asia.Here we compare data on migration phenology and morphology from two bird ringing stations in eastern Russia,situated at similar latitudes but with a longitudinal difference of 1500 km,to hypothesise migration patterns.We found significant differences in timing between the two sites(birds migrated significantly earlier in spring and significantly later in autumn in the east),suggesting longitudinal migration as a result of migration detour.However,morphological differences show a less clear pattern.We argue that most Siberian landbirds might opt for a detour through the Russian Far East instead of a direct route in order to avoid unfavourable stop-over habitat in Central Asia.However,tracking studies will be necessary to prove this.
基金supported by the German Ornithologists’Society,the Forderkreis Allgemeine Naturkunde(Biologie)e.V.and the NABU RVE e.VLB’s work was supported by the Campus Hungary Studentship and the Hungarian National Young Talent Studentship
文摘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.
文摘Stopover niche utilization of birds during migration has not gained much attention so far,since the majority of the studies focuses on breeding or wintering areas.However,stopover sites are crucial for migratory birds.They are often used by a multitude of species,which could lead to increased competition.In this work,we investigated niche use of 8 migratory and closely related Emberiza bunting species at a stopover site in Far East Russia,situated on the poorly studied East Asian flyway.We used bird ringing data to evaluate morphological similarity as well as niche overlap on the trophic,spatial,and temporal dimension.Bill morphology was used as a proxy for their trophic niche.We were able to prove that a majority of the species occupies well-defined stopover niches on at least one of the dimensions.Niche breadth and niche overlap differ between spring and autumn season with higher overlap found during spring.Morphological differences are mostly related to overall size and wing pointedness.The temporal dimension is most important for segregation among the studied species.Furthermore,all species seem to exhibit a rather strict and consistent phenological pattern.Their occurrence at the study site is highly correlated with their geographic origin and the length of their migration route.We assume that buntings are able to use available resources opportunistically during stopover,while trying to follow a precise schedule in order to avoid competition and to ensure individual fitness.
