How much of the inter-individual variation in routes and the migratory schedule is genetically determined?

This project aims at describing and explaining the individual variation in the migration behaviour in a wild population of Alpine swift. Individuals differ in the non-breeding sites they visit, the route they take, the use of stop-over sites, and the timing of their journey. We are particularly interested in linking this variation to different factors, such as sex, age, life history events, the year, weather circumstances, and relatedness between individuals. Knowing heritability in particular is key to understand how fast long-distance can respond evolutionarily to a changing environment.

Models to calculate heritability are data hungry. For this purpose, we collect full annual tracks using multisensor geolocators of many individuals with available information of their relatedness within the breeding population. We can infer relatedness of offspring from observing their parents during reproduction or genetically using microsatellites. Data are collected in Biel, Solothurn, Luzern, Lenzburg, Seengen, and Baden in Switzerland and at two sites in Turkey, where also long-term monitoring programs are in place, providing us with key life-history information on every individual.

We seek answers to some of the very longstanding fundamental questions in migration research: Are long-distant migrants able to adjust to a changing environment and is the mechanism flexible enough to also adapt quickly in time? The key is how much of the variation in behaviour can be attributed to the individual and how much is owned to environmental stochasticity. The Alpine swift system holds a great power as it allows us to link full annual cycle migration behaviour with the complete life history of individuals and repeated tracking of the same individual between consecutive years.

A decade of tracking the Alpine swifts with multisensor geolocators has unfolded a diversity of migration behaviour in this species. We have identified non-breeding sites in the Sahel zone where birds of different populations aggregate, and individuals seem to consistently visit the same cluster every year. Timing of the annual cycle is influenced primarily by length of the period with good feeding conditions at the breeding ground. Data on air pressure also revealed that birds are regularly ascending 1 km for a short time at around twilight outside the breeding season for unknown reason.

• Yrd.Doç.Dr. Hakan KARAARDIÇ (Hakan Karaadıç), Alanya Alaaddin Keykubat University Education Faculty, Math and Science Education Department
• Strahil Georgiev Peev, Institute of Biodiversity and Ecosystem Research
• Raül Aymí, Catalan Ornithological Institute
• Gwenael Jacob, Departement of Biology

• The Swiss Federal Office for the Environment (FOEN) contributed financial support for the development of the tags (grant UTF 400.34.11)
• Wolfermann-Nägeli foundation granted supported for fieldwork