Movements of Coal, Marsh and Willow Tits in Britain

Abstract

An analysis of the British Trust for Ornithology's ringing recoveries of Coal, Marsh and Willow Tits is described. For all three species, ca 80% of the recoveries were within 5 km of where ringed. The numbers of recoveries at 5 km or over decreased with increasing distance, and in the case of the Coal Tit corresponded approximately to an exponential distribution. Also for this species, the geometric mean distance moved over 5 km is correlated with the Garden Birds Feeding Survey Index (itself inversely related to the availability of natural foods); and more first‐year than adult birds moved at least 5 km. For all three species, the orientations of movements over 5 km were random. It is suggested that these movements are dispersive in nature and, in the case of the Coal Tit at least, occur in response to (or possibly in some cases in anticipation of) food shortages. Three cross‐Channel movements show that Continental Coal Tits do overwinter in Britain at least in some years. The ratio of recoveries of Mars...