The wing-moult of Cory's Shearwater, Calonectris diomedea, off Nova Scotia

Abstract

The progress of the moult of the primary flight-feathers of Cory's Shearwaters, Calonectris diomedea, is described from field observations made of southern Nova Scotia 15-31 August 1988 and from earlier cruises. Wing-moult begins after the end of June, and is in progress during August. It is theoretically possible that these birds were active breeders, foraging at long range from colonies in the Azores. However, the timing of their wing-moult makes this unlikely. Greater Shearwaters, Puffinus gravis, showed little sign of wing-moult in August, confirming the earlier conclusion that this species moults as soon as it arrives off Atlantic Canada in May-June.