Age determination, wing‐feather colour and wing‐length change in Snow BuntingsPlectrophenax nivalis

Abstract

Several recent publications have indicated difficulties in ageing Snow Buntings wintering in Scotland because two races occur and characteristics based on plumage show overlap between age, sex and racial categories. An alternative method of age determination, based on wear and colouration of the longest tertial, inner secondary coverts and central tail feathers, is described and evaluated. In support of the technique, birds aged as one‐year‐olds showed significant increases in the extent of the white wing‐patch and in wing‐length when recaptured the following winter, while those aged as adults did not.