Wintering and migration strategies of Slavonian Grebes Podiceps auritus breeding in Iceland

Slavonian Grebes Podiceps auritus breeding in Iceland moult on freshwater, before migrating to the seas around the British Isles for the winter.

The aims were to describe the migration strategies and identify wintering areas of Slavonian Grebes breeding in Iceland.

Geolocators were fitted to 37 Slavonian Grebes breeding on two lakes in north-east Iceland from 2009 to 2012. Of these, 19 were recovered and provided useful data on wintering areas and migration timing.

The results indicated that the grebes moulted on freshwater lakes before gradually moving to the sea and later migrating to the wintering areas. Most of the birds wintered on the sea around the British Isles. However, there was surprisingly high variation in wintering strategies and little overlap of wintering areas. Grebes tracked for consecutive years showed high wintering philopatry.

Individual Slavonian Grebes may be vulnerable to local environmental conditions, but the high variability in wintering strategies and relatively large non-breeding distribution is expected to make the population generally less sensitive to local environmental conditions in the wintering areas over the long term.