Notes on the Moult of the Eastern Great Reed Warbler Acrocephalus arundinaceus orientalis in the Breeding Grounds

Abstract

During the course of an ecological study of the Eastern Great Reed Warbler Acrocephalus arundinaceus orientalis at Lake Biwa, some information on its moulting was obtained. From 1976 to 1978, 24 birds were trapped after July and 9 of them, including both young and adults, were either during or after moult. Their stage of moult agrees closely with the progress of moulting in young and adults at Fukushimagata, estimated from the moulting records of the BMRC banding team. Some birds that bred in the study site were confirmed to start moult there and it is expected that they complete it not far from their breeding sites. Characters for ageing were also referred to.