Spring arrival of adult Lesser Black-backed Gulls Larus fuscus nesting in Guernsey, Sark and Herm, Channel Islands

Abstract

Lesser Black-backed Gulls Larus fuscus nest in all the Channel Islands, with strongholds in Alderney and Sark. Breeding numbers in the islands (c. 1,730 pairs) appear presently stable, and the whole population is believed to leave the islands in winter. A colour-ringing programme began in 2008 and the timing and pattern of arrival for 125 colour-ringed adults, believed to be local breeders, was recorded at a landfill site on Guernsey from 1 January to 8 May 2010. Birds arrived back from 15 January to 1 May. Arrivals were slow initially, with only 6% back by mid February and 22% by the end of February. Peak arrival was from 27 February to 10 March, when 34% of birds were first recorded, and by the end of March 82% of birds had returned. Males did not arrive earlier than females. Five birds left the Channel Islands again soon after arriving, although all returned within a few days or weeks. Winter 2009/10 was unusually long and cold in the Channel Islands, and most of Western Europe, and further study should ascertain whether the arrival pattern of Lesser Black-backed Gulls in spring 2010 was affected by the harsher than average winter weather.