Fuelling in front of the barrier - are there age based behavioral differences in Garden Warblers Sylvia borin?

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1 Natural History Museum of Crete, University of Crete, Iraklion, Greece
2 Department of Zoology, Stockholm University, Stockholm, Sweden
3 Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, Iraklion, Greece
4 Department of Environmental Research and Monitoring, Swedish Museum of Natural History, Stockholm, Sweden
DOI
10.7287/peerj.preprints.244v1
Published
Accepted
Subject Areas
Animal Behavior, Ecology, Zoology
Keywords
bird migration, Sahara crossing, Eastern Mediterranean, stopover, Crete, Radio tracking
Copyright
© 2014 Barboutis et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Cite this article
Barboutis C, Henshaw I, Kullberg C, Nikolopoulou S, Fransson T. 2014. Fuelling in front of the barrier - are there age based behavioral differences in Garden Warblers Sylvia borin? PeerJ PrePrints 2:e244v1

Abstract

Garden Warblers Sylvia borin were studied during autumn stopover in Crete before crossing the barrier of the Mediterranean Sea and the Sahara desert. Birds followed with transmitters show extensive stopover periods, which were longer in first-year birds, 16 days, compared with adult birds, 14 days. The distribution of body masses from birds trapped in fig trees were used to estimate the departure body mass and the results found indicate that both age categories on average depart with a fuel load close to 100% of lean body mass. The movement of transmitter birds shows differences between first-year and adult birds. Adult birds move further away from the release site and many also left the study area. Several were found settled outside the study area, up to 17 km away, indicating that they regularly make longer stopover movements. It is suggested that this might be a result of that they return to a place where they stayed during an earlier migration. It was shown that stopover site fidelity exists and nine garden warblers were recaptured in the area during a following autumn. The results found highlights the importance of stopover areas close to the Sahara desert.