Deuterium (δD) in Feathers of Mongolian Waterbirds Uncovers Migratory Movements

The need for better understanding of migratory movements of wild birds in Asia promoted an evaluation of the usefulness of deuterium in feathers (δDf) to assign origins. Feathers were sampled from Bar-headed Geese (Anser indicus), Whooper Swans (Cygnus cygnus), Mongolian Gulls (Larus vegae mongoliens), Curlew Sandpipers (Calidris ferruginea) and Pacific Golden Plover (Pluvialis fulva) in north-central Mongolia, from June to September 2007. Univariate statistical analyses were performed to test for differences between study sites for all species and between growing (blood) and previously grown (non-blood) feathers only for Bar-headed Geese. Values of δDf in actively growing feathers generally agreed with those expected from integrated isotopic signals in precipitation expected for sampling sites. Values of δDf from adult migrant birds also indicated varying degrees of movement from north to south expected from the movement of these species in Asia. These results show promise for the isotope approach for establishing origins of molt of migratory waterbirds in Asia in a cost-effective manner without the need for mark and recapture. Projects required to track movements of waterbirds in Asia could benefit by incorporating this approach into study design. However, greater refinement of the δDf isoscape for Asia is now needed.