A global look at the Stonechat species-complex

Stonechats are widely distributed across Europe, Asia, and Africa. They vary greatly in migration, from residency to long-distance, and in route choice. We will test to what extent migration differs locally and how this links to genes, using an extreme barrier as a test case. Moreover, the Stonechat taxon is now seen as a complex consisting of species that are difficult to distinguish. Assignment of individuals to species or location is important as Asian Stonechats are increasingly observed in Europe. We develop genetic tools to identify Stonechat origin from DNA contained in their feathers.

We characterize migration of Stonechats breeding north of the Tibetan plateau by tracking them with geolocators. We track individuals from populations that are suspected to circumvent this barrier on Westerly versus Easterly routes. We also build a “genoscape” to assign migrants to their native populations, from Central Asia to Western Europe. This genetic map is based on a broad range of sampling sites (see gallery) and will enable assignment using DNA extracted from a small number of feathers. We also compare phenotypic features of Stonechats that are thought to be linked with migration.

The ability of birds to carry out stunning journeys at the right place and time continues to fascinate us humans. This project aims to give new insights into migration. At the same time, a better understanding of the extent of genetic determination of migration is important to assess the risks, and interpret the negative populations trends, of many migratory species. Likewise, tools for assignment of migrants to their native locations will aid conservation efforts, for example for linking trends in the breeding population to their non-breeding habitats.

Our first geolocator data support the idea that some individuals from the suspected Westerly and Easterly migrating populations indeed circumvent the Tibetan Plateau, despite a much longer journey (see gallery). Still, others migrated intermediately, similar to the route choice of a high-elevation population that breeds on the Qinghai-Tibetan Plateau. We also find evidence for genetic differences and for morphological features associated with migration behaviour, such as smaller skulls with increasing migration distance.

• Tianhao Zhao
• Wieland Heim
• Bregje Wertheim
• Miriam Liedvogel
• Kristen Ruegg
• Yuri Anisomov
• Mariëlle van Toor
• Fumin Lei
• Susanne Akesson
• Magnus Hellström
• Gang Song
• Staffan Bensch