Ringing recoveries of red‐throated diversGavia stellatain Britain and Ireland

Abstract

Using the ringing recoveries on the BTO ‘s files the movements of Red‐throated Divers are analysed. All of the British and Irish recoveries were from birds ringed in Shetland and Orkney. The recovery rate was 7.5%, high for a seabird but perhaps reflecting the number recovered in nets, two‐thirds of the recoveries when the circumstances were specific. The oldest bird was 16.5 years old. 65% of the recoveries were between May and August with a slight mid‐winter peak in January. First winter birds were recovered as far south as central France. In their first summer recoveries came from as far away as Devon, Ireland and Norway with a quarter of the birds back in their natal area. In their second winter birds were again widely distributed but by their second summer two‐thirds of the recoveries were in the natal area with the others in the north of Scotland. For birds older than two years, the winter recoveries were again widely dispersed (but not as far south as the younger birds), with slightly more west coast recoveries than on the east coast. In summer, nearly all of the recoveries of adult birds came from within the area of ringing. Recoveries of foreign ringed birds have come from Greenland (3), Sweden (1) and Finland (4). The birds from Shetland and Orkney nearly all leave their native sites during the winter, and are widely dispersed around the coast. In summer, nearly all of the adults and an annually increasing number ofimmatures are in the Northern Isles, making the population very vulnerable to a summer pollution incident.