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Bats have evolved migration to escape unfavourable climatic conditions. However, their migratory flyways and the way how they surmount geographical barriers are still unknown. The Jungfraujoch in the Swiss Alps is a mountain covered in permafrost (3460m ASL), known colloquially as the “Top of Europe”. Using broadband ultrasound recorders, we tested the occurrence of bats at the high altitude research station. In 36 nights, we recorded 268 bat call sequences of 8 species, including all European long-distance migrant bats. Since no feeding buzzes were recorded, we assume the bats were on transit. This is the first evidence to show that migrating bats can fly at unprecedented altitudes to cross the Alps. This feat outperforms the spectacular behaviour of the high altitude foraging bat Tadarida brasiliensis. Our findings shed light on the bats’ migratory flyways and demonstrate that the field of aeroecology can still uncover unexpected perspectives on the behaviour of bats.
This is the first draft to report observations of bat migration at unprecedented altitudes crossing the European Alps. It is a case study which benefitted from the invitation to use the High Altitude Research Station Jungfraujoch in the Bernese Alps of Switzerland. We are particularly interested in suggestions where to finally publish such a case study which sheds light on the possible migration paths of a multitude of bat species across a geographical barrier like the alpine arch.