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How flexibly can Alpine swifts (Apus melba) adjust their migration behaviour to a changing environment?

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

Migratory species commute between locations and climate zones along the annual cycle. How the organization of this cycle is determined remains unclear. Migratory behaviour is partly genetically encoded but also requires a plastic component (e.g., the temporal schedule) to adjust for variability in the environment. In this project we aim at quantifying the amount of heritability for different migratory traits (route, stop-over, timing). We track individuals of various degree of relatedness from different populations and in different years to tease apart genetic basis from plasticity.

Domain Research
Unit Bird Migration
Topic Ecology, Evolution, Migratory Birds
Habitat rocky terrain, settlements
Project start 2009
Project status ongoing
Project management Christoph M. Meier
Project region Aargau, Bern, Lucerne, Solothurn, Africa, Europe


Project objectives

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.

Project partner(s)

  • 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

Financial support

  • 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



Betroffene Vogelarten

Bird species
Alpine Swift
When the Common Swifts have left as from the end of July, the Alpine Swifts have the airspace above our towns to themselves. Bands of adult birds and their young zoom about high above chasing each other and twittering loudly in their aerial displays. The large falcon-like Alpine Swifts occur in t...
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Other resources
Neues aus dem Jahreszyklus des Alpenseglers (in German)
Bird Migration link

Bird Migration

We research migratory birds from their breeding grounds to Africa and lay the foundations for their protection beyond national borders.

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