Ageing Wrens Troglodytes troglodytes using the barring pattern across remiges

Abstract

Two different ageing criteria are in common use for Eurasian Wrens Troglodytes troglodytes under the BTO Ringing Scheme, and both have their adherents and detractors. The identification of moult limits after the partial post-juvenile moult is effective for most birds in late summer and autumn, but becomes more difficult as plumage wear and damage increases in spring. The number of pale spots on the fourth primary is also effective in British birds in autumn and winter, but intermediate birds are not uncommon and plumage wear also reduces its usefulness. This paper proposes a third method, using the barring pattern across the secondaries and inner primaries of the partly opened wing. In contrast to the two established methods above, this criterion is unaffected by plumage wear and damage, and remains easily recognisable throughout the year. © 2012 British Trust for Ornithology.