Survival, winter population stability and site fidelity in the TurnstoneArenaria interpres

Abstract
A study was made of the stability of a population of Turnstones wintering on a rocky shore. Marking birds individually revealed that the majority of Turnstones within the 6 km-long study area were resident from autumn until April or May each year. A greater proportion of juveniles than adults disappeared soon after marking, due either to higher vagility or to mortality. Ninety-five per cent of adult Turnstones resident in the study area at the end of each winter returned the subsequent autumn and the adult annual mortality was estimated to be under 15%. There was little variation between or within years in the numbers of birds present, resulting in a wintering population that was highly stable from year to year. Birds left the study area at an accelerating rate from February to May. The timing of migration of individual Turnstones was consistent from year to year. We suggest that birds leaving before mid-April were moving to other areas within Britain [UK] to build up the fat reserves for the main migration.