Timing of migration and African non-breeding grounds of geolocator-tracked European Pied Flycatchers: a multi-population assessment

Abstract

Using light-level geolocators, eight European Pied Flycatchers (Ficedula hypoleuca) from two breeding sites in Czechia were tracked. We also gathered all available geolocator tracks on 76 individuals from four European populations and compared the timing of annual cycle events and the African non-breeding sites among all populations. Individuals from both Czech breeding sites had overlapping migration events and non-breeding locations. Four individuals resided in the southwestern edge of Mali, two in Burkina Faso, one in Guinea, and the easternmost one in the Ivory Coast. On average, the birds left the Czech breeding grounds on 8 August and took between one to three stopovers during autumn migration. Birds crossed the Sahara on its western edge on average on 13 September. The mean arrival to the African non-breeding grounds was 47.5 days after departure on 2 October (range 10 September to 10 October). One bird showed intra-tropical movement within West Africa when after a 60-day residency it moved approximately 3° westwards. Estimated locations at the African non-breeding grounds overlapped among tracked birds from five European breeding sites. However, statistically, we could detect longitudinal segregation in two clusters. Birds from the British and Finnish breeding populations shared non-breeding grounds and were located in Africa west of the second cluster of the birds from the Czech and Dutch breeding populations. We show considerable population-specific differences in the timing of annual cycle events. Birds from Dutch breeding sites were the first in all three phases—departure from breeding sites, Sahara crossing and arrival to African non-breeding grounds, followed by the British, Czech, and Finnish birds, respectively. All tracked flycatchers so far fill only the western part of the African non-breeding range. For a complete understanding of the migration pattern in the species, we highlight the need for tracking studies from the eastern part of the range.