Seasonal variation in migration routes of Common Whitethroat Curruca communis

Although geolocator tracking of small passerines has become commonplace in the last two decades, this tool is still underutilized for gathering natural history data of migration in many species. Common Whitethroat (Curruca communis) is one of the most numerous Afro-Palearctic migrants. However, our knowledge of the species’ migration ecology remains limited. Here, we combine ring-recovery analyses with geolocator tracking to describe migration routes and population-specific non-breeding areas in this long-distance migrant. Linkages between breeding, passage and non-breeding areas based on ring-recovery records revealed a strong correlation in longitudes, indicating parallel migration system and population-specific non-breeding grounds in whitethroats. Migration route simulation using EURING data suggested a possible migratory divide in Central Europe in autumn, while broad front migration across the Mediterranean occurs in spring. Geolocator-tracked whitethroats from Czechia (Central Europe) and Latvia (North-eastern Europe) migrated to non-breeding sites in Central Africa, where they first resided in the Sahel region before moving farther to a second non-breeding site in November/December. Major stopovers were associated with crossing of ecological barriers. A single Latvian bird with a repeat track showed similar migration patterns in both years, possibly visiting the same non-breeding sites in consecutive years. Both ringing and tracking data revealed clockwise loop migration between breeding and non-breeding sites.