The wing-moult of fulmars and shearwaters (Procellariidae) in Canadian Atlantic waters

Abstract

The progress of the moult of the primary flight-featehrs on non-brreeding Northern Fulmars, Fulmarus glacialis, and Greater and Sooty Shearwaters, Puffinus gravis and Puffinus griseus, is described from field observations made in Canadian Atlantic waters, and compared with observation and specimen data from elsewhere in the ATlantic, and from the north-west Pacific and the Candadian High Arctic. Brief notes on wing-moult in Manx, P. puffinus, and Cory's shearwaters, Calonectris diomedea, are added. The wing-moult of adult Northern Fulmars is apparently completed by April. That of non-breeding birds begins in May or earlier, and is completed by October. The Light and Dark plumage colour-morphs do not differ in this timing. Greater Shearwaters begin to moult as soon as the first birds -- presumably post-breeding adults -- reach Canadian waters in May, peaks in June on the Grand Banks, and is virtually completed by the end of August. Sooty Shearwaters undergo a wing-moult when they arrive in the north-east Pacific, but do not do so i n the North Atlantic. It is suggested that the relatively small Sooty Shearwater population which migrates to the North Atlantic is made up of immature birds.