|Short description:||To understand how the onset of nocturnal departure times is controlled in long-distance songbird migrants|
|Description:||Most nocturnal songbird migrants travel without social guidance between the breeding and wintering areas. To arrive at the correct place and time, their innate migration program defines the spatiotemporal organisation of migration and their reactions to the environment. When birds are kept in cages during migration, they show nocturnal activity, “migratory restlessness”. The temporal pattern and intensity of migratory restlessness is endogenously controlled. However, changes in photoperiod, temperature, and body condition modulate the seasonal pattern. These factors also influence the departure probability of a migrant at a stopover site. Although the circannual and circadian rhythms in migrants and their realised migration behaviour are well studied, we have little information (i) about the start of nocturnal migratory restlessness and the onset of nocturnal migration, (ii) whether both traits are temporally related, (iii) whether they are strongly endogenous controlled, and (iv) which exogenous factors influence the timing of both traits.|
The onset of nocturnal migration defines the potential flight range per night. The seasonal sum of all potential flight ranges per night influences total speed of migration which in turn affects the timing of migration. For our understanding of migration it is essential investigating which endogenous and exogenous factors influence the onset of nocturnal migration.
By combining cage experiments to determine the start of nocturnal migratory restlessness and radio telemetry to identify the onset of nocturnal migration for the same individual we will (i) describe the temporal pattern of both traits, (ii) whether both traits correlate temporally with each other and identify how (iii) endogenous and (iv) exogenous factors influence the timing of both traits within the night. To this end, Northern Wheatears (Oenanthe oenanthe) will be caught on Helgoland a small island in the North Sea. On migration the nominate form breeding in Scandinavian and the leucorhoa subspecies breeding on Island, Greenland, and in Canada pass regularly Helgoland. As they all winter in sub-Sahelian Africa, populations have depending on their breeding areas different remaining migration distances from Helgoland in spring but not in autumn. This framework allows testing differences in both traits in respect of total migration distance [endogenous factor], remaining migration distance, temperature, body condition and weather [all exogenous factors].
|Project contact:||Heiko Schmaljohann, Volgelwarte Helgoland|
|Researchers:||Heiko Schmaljohann, Volgelwarte Helgoland|
Mario de Neidels, Institute of Avian Research "Vogelwarte Helgoland"
Zephyr Züst, Institute of Avian Research (Vogelwarte Helgoland)
|Species:||432 Northern Wheatear|
75 Eurasian Blackbird
1 European Robin
1 Rock Pigeon (Feral Pigeon)
|Creation date:||2015-01-01 00:00:00 UTC|
|Data visible to the public:||Mobile GPS data|
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