Population trends of Swallows Hirundo rustica breeding in Britain

摘要: Capsule There are regional and habitat differences, but no long-term decline in numbers. Aims To review the evidence for declining Swallow populations Britain, based on British Trust Ornithology's long-running Common Birds Census (CBC) suggest possible causes. Methods Trends were fitted to CBC data 1964–98 using a generalized linear modelling framework analysed with regard specific regions habitats. Current use, particularly of different farming types, was characterized from Breeding Bird Survey. Correlations between population size loss nest-sites rainfall non-breeding grounds examined. Results Although numbers show large annual fluctuations, there is plots. Numbers seem have declined farms eastern England non-farmland habitats, not correlated changes cattle or an index nest-site availability. The number...