Population status and reproductive biology of the Mute Swan, Cygnus olor, at Long Point, Lake Erie, Ontario

Abstract

During 1991 -1992, a study of the population status and breeding biology of the Mute Swan, Cygnus olor, was carried out at Long Point, Lake Erie. Thirty-one pairs with broods were located, 9 in 1991, 22 in 1992. Brood size ranged from 2 to 10, with 4 and 5 being the most frequent. Brood size averaged 4.9 at hatching and 3.1 at fledging, a value which compares with that of rapidly expanding populations in Europe. Aerial surveys in fall at Long Point revealed a peak total of 148 in 1991 and 172 in 1992, an increase of 14 %. A high proportion of "Polish" morph juveniles were detected.