Estimation of light range of migrant Leaf-Warblers at Lake Baikal

Doi: https://doi.org/10.13157/arla.67.1.2020.sc1

Authors: László BOZÓ, Tibor CSÖRGŐ and Yury ANISIMOV

E-mail: bozolaszlo91@gmail.com

Published: Volume 67.1, January 2020. Pages 57-67.

Language: English

Keywords: Radde’s warblers, Dusky Warblers and Leaf-warblers

Summary:

The migration of Siberian passerines is little known, although the number of studies has been increasing recently. However, due to the lack of recoveries of ringed individuals along the East Asian migratory flyway, and the size-dependent limitation on the use of geolocators, studies of the migration routes of small leaf-warblers are scarce. The only promising method is flight range estimation by using biometric parameters to identify migration distances and locate possible stopover sites along the flyway. The aim of this study was to estimate the flight ranges of migrant Radde’s warblers Phylloscopus schwarzi, Dusky Warblers P. fuscatus and Pallas’s Leaf-warblers P. proregulus at a stopover site next to Lake Baikal, Russia. For the analyses, we used the body mass, fat score and wing-length data of 809 individuals, which were trapped with mist-nets during the autumn migration periods between 2012 and 2017. Our results show that body mass, but not wing length, increased significantly among individuals with increasing fat scores in all study species. The estimated flight ranges of Pallas’s Leaf-warbler (724km) and Radde’s Warbler (510km) were similar to those of birds studied in a different part of Siberia, and the number of calculated stopovers was also similar between the two areas. In contrast, Dusky Warblers trapped at our study site were estimated to fly shorter distances (217km) and therefore must have stopped more frequently on their way to the wintering grounds.

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