Determinants of spring migration departure decision in a bat

Migratory decisions in birds are closely tied to environmental cues and fat stores, but it remains unknown if the same variables trigger bat migration. To learn more about the rare phenomenon of bat migration, we studied departure decisions of female common noctules ( Nyctalus noctula ) in southern...

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Bibliographic Details
Published in:Biology Letters
Main Authors: Dechmann, Dina K. N., Wikelski, M., Ellis-Soto, D., Safi, K., O'Mara, M. Teague
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 2017
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Online Access:http://dx.doi.org/10.1098/rsbl.2017.0395
https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2017.0395
https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2017.0395
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Summary:Migratory decisions in birds are closely tied to environmental cues and fat stores, but it remains unknown if the same variables trigger bat migration. To learn more about the rare phenomenon of bat migration, we studied departure decisions of female common noctules ( Nyctalus noctula ) in southern Germany. We did not find the fattening period that modulates departure decisions in birds. Female noctules departed after a regular evening foraging session, uniformly heading northeast. As the day of year increased, migratory decisions were based on the interactions among wind speed, wind direction and air pressure. As the migration season progressed, bats were likely to migrate on nights with higher air pressure and faster tail winds in the direction of travel, and also show high probability of migration on low-pressure nights with slow head winds. Common noctules thus monitor complex environmental conditions to find the optimal migration night.