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

ABSTRACTCapsule Slavonian Grebes Podiceps auritus breeding in Iceland moult on freshwater, before migrating to the seas around the British Isles for the winter.Aims The aims were to describe the migration strategies and identify wintering areas of Slavonian Grebes breeding in Iceland.Methods 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.Results 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.Conclusion 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. AcknowledgementsWe thank Ellen Magnúsdóttir for technical assistance and Ib Krag Petersen for advice regarding the geolocators and attachment methods. We are also grateful to landowners at lake Víkingavatn and the Vatnajokull National Park authorities for access to the nesting area of the Slavonian Grebes. Finally, we warmly thank Sesselja Gudrun Sigurdardóttir and Sunna Bjork Ragnarsdóttir for their fieldwork participation. All work carried out for this study complies with the current law and regulations in Iceland. Ringing permit was provided by the Icelandic Institute of Natural History.Disclosure statementNo potential conflict of interest was reported by the author(s).