Population dynamics of seabirds in the Firth of Clyde

Abstract

Synopsis Marked interspecific differences in recent population trends have been recorded for seabirds breeding in the Firth of Clyde. Auk populations have remained comparatively stable, while considerable reductions have taken place in tern and kittiwake numbers. Shags, cormorants, gannets and great black-backed gulls have all increased, as have fulmars and herring gulls. The striking increases in the latter two species are considered in detail. To some extent, these population changes can be related to differences in the feeding ecology of the various seabirds; in particular the variation in the number of breeding terns is related to variation in food availability.