The size and migratory origins of the population of Hen Harriers Circus cyaneus wintering in England
Capsule The majority of Hen Harriers Circus cyaneus that spend the winter in England are derived from the British breeding population. Aims To investigate the popular hypothesis that Hen Harriers which over-winter in England are derived principally from breeding populations in mainland Europe. Methods Demographic data were used to estimate numbers of Hen Harriers in Britain at the end of the breed
