Doi: https://doi.org/10.13157/arla.72.1.2025.sc1
Authors: Jan ŠKRÁBAL, R. RAAB and Ivan LITERÁK
E-mail: skrabalh@seznam.cz
Published: Volume 72.1, January 2025. Pages 81-92.
Language: English
Keywords: bio-tracking, migration, Milvus milvus, raptors and telemetry
Summary:
Migration is a complex phenomenon influenced by several factors, including environmental conditions and individual preferences. We investigated the unique loop migration of Central-European Red Kites Milvus milvus to and from their wintering grounds in Italy. Utilising telemetry data from nineteen tagged birds, we analysed migration routes and route consistency in relation to wind conditions. Our results revealed distinct patterns between autumn and spring migrations. During autumn, most birds chose a shorter route over the Adriatic Sea, facilitated by the katabatic Bora wind, while in spring, the majority chose a continental route along the east coast of Italy. Despite the fact that the risky sea-crossing offered a shortcut, migration duration remained similar, as some birds waited along the Croatian coast for supportive winds. Route choice showed high consistency, suggesting a fixed strategy influenced by experience and individual preference. Wind conditions played a crucial role, with the Bora wind facilitating autumn migrations but hindering spring crossings. Nevertheless, despite adverse conditions, some birds opted for sea crossings in spring, indicating flexibility in response to atmospheric conditions. Our findings underscore the ecological importance of coastal stopovers and over-sea passages for Red Kites and, potentially, other soaring raptors. Overall, our study provides useful insights into the intricate relationship between environmental factors and migration strategies.
