First data on complete summer moult in the Great Reed Warbler (Acrocephalus arundinaceus) in northern Italy

Abstract

Complete summer moult in the Great Reed Warbler (Acrocephalus a. arundinaceus) is a rare phenomenon, and only two cases have so far been reported for Europe. In 5 years of summer ringing in Val Campotto, Northern Italy, 12 different individuals were found in complete moult. Only the two innermost primaries are generally renewed, with more advanced stages of moult involving up to 6 primaries, the tertials and the first secondaries. A single bird controlled in three subsequent years was always found at a similar degree of primary moult.