THE CHANGING STATUS OF THE LESSER BLACK-BACKED GULL LARUS-FUSCUS IN IRELAND

Major changes in the status of the populations of the large gull speci es in Ireland have taken place over the past fifteen years. While mark ed declines have occurred in the numbers of breeding herring gulls Lar us argentatus, over more or less the same period there has been a shar p increase in the population of lesser black-backed gulls L. fuscus. M oreover, this increase has not been confined to the numbers breeding b ut has also involved considerable changes to the size of the overwinte ring population. This paper describes the change in status of the less er black-backed gull in Ireland with particular emphasis on the rate o f increase of the breeding population and the geographical distributio n and numerical strength of the overwintering flocks. The increase in breeding numbers of lesser black-backed gulls is most marked at coasta l sites in the south and south-east of Ireland, where annual increases in excess of 14% have been recorded, A survey oi overwintering lesser black-backed gulls carried out as part of this study has shown that t he population has exceeded 12,000 birds. The overwintering flocks are again mostly confined to the south and south-east or Ireland.