Stopover and fat accumulation in passerine birds in autumn at Ottenby, southeastern Sweden

Abstract

Stopover duration and fat accumulation were studied during autumn migration at two sites near Ottenby, Oland, SE Sweden in 1985 and 1986. Post juvenile moult was scored on juvenile birds. In several of the species fat class and body mass increased with day of season (thrush nightingale Luscinia luscinia, barred warbler Sylvia nisoria, and whitethroat S. communis), while in the lesser whitethroat S. curruca there was a reduction in fat class and body mass with day of season. The highest daily increase in body mass was 2.7% in a willow warbler Phylloscopus trochilus and a red-backed shrike Lanius collurio, while a barred warbler showed a maximum daily body mass increase of 2.4%,. The duration of stopover in migrants varied between two and seven days. -from Authors