Wing length changes in individually-marked Blackbirds Turdus merula following moult

Abstract

Leverton, R. 1989. Wing length changes in individually-marked Blackbirds Turdus merula following moult. Ring. & Migr. 10: 17–25. 96 Blackbirds which had been ringed as first-years were remeasured after their first moult. The average wing length of males increased by 3.25mm, and of females by 2.07mm, but there was considerable variation. Smaller birds tended to show a greater increase. 91 adult Blackbirds were remeasured after moult. Males showed an average increase of 0.53mm per moult, but for females the change was not significant. Abrasion and measurement inconsistency are quantified. Possible reasons for the shorter wing length of young birds are discussed.