Ageing Dunnocks Prunella modularis using plumage characteristics

Abstract

Iris colour has long been regarded as the only reliable way of ageing Dunnocks Prunella modularis. There are limitations with this method, namely that it can only be used during late summer and autumn when a difference in iris colour exists between young (first-year) and adult birds. By late autumn, the method is no longer reliable and many Dunnocks are thus left unaged. Differences in plumage exist between young and adult birds. These differences have an advantage over iris colour since they are observable year-round. A number of differences between young and adult birds have been found, notably in the greater coverts and primary coverts. These features allow Dunnocks to be reliably aged when ageing by iris colour is not possible. © 2013 Copyright British Trust for Ornithology.