The Hen HarrierCircus cyaneusWinter Roost Survey in Britain and Ireland

A survey of Hen Harrier winter roosts traced 202 sites in Britain to the end of 1985/86 winter, and 12 in Ireland. Communal roosting had been recorded at more than 90% of sites, and 43% were known to be used every winter. Of reported sites 39% were in E England, where coverage was undoubtedly more comprehensive. The majority of sites in England were reported to have been discovered since the mid 1970s. Hen Harriers almost invariably roosted amongst rank ground vegetation, in a variety of open habitats, and 28% of sites were on d rtl ground. Most sites were at low altitudes, but some had been found up to 427 m above sea level. Co-ordinated counts at roosts recorded maximum overall numbers at mid-winter in both 1983/84 and 1984/85, although the pattern of occupancy varied between regions. No estimate could be made of the sizes of the winter populations in Scotland, Ireland and Wales, but extrapolation of counts to estimate the numbers wintering in England indicated populations which peaked at about 400 bird...