The Decline of the Corncrake Crex crex in Britain and Ireland in Relation to Habitat Change

Abstract

Censuses of singing male corncrakes Crex crex (L.) in 1978/79 and 1988 on agricultural land in Britain and Ireland indicated that numbers had, on average, declined by 30% during this time period in areas for which the two censuses were comparable. This represents the continuation of a long-term decline. However, population changes differed among areas, ranging from a 72% decline to a 15% increase. Areas in which the greatest declines had taken place tended to be those in which a high proportion of sites which held corncrakes in 1978/79 had ceased to be occupied by l988. Sites were identified that were occupied by corncrakes in 1978/79 and that had ceased or continued to be occupied by singing males in 1988. Vegetation surveys were carried out in 1988 at all such sites that could be located with precision