1911] Swarth: Alaska Expedition of 1909. 39 



Mergus americanus Cassin. American ]\Ierganser. 



Though several species were far more abundant in places, 

 there was no other duck so generally distributed throughout 

 the region explored, for American mergansers were seen, in 

 greater or less numbers, at every point we visited. At 

 Kupreanof and Kuiu islands, during April, they were fairly 

 numerous and still in flocks, though at the end of the month 

 they began to pair off. At Coronation and Warren islands 

 (^lay 12 to 23) pairs of American mergansers were seen daily, 

 while the species was quite common at all the various points 

 touched at along the west coast of Prince of Wales Island 

 between May 6 and 29. At San Alberto Bay (May 2-4 to 26) a 

 female was several times seen flying into a clump of trees by 

 the water's edge where there were several dead stubs, and in 

 one of these she probably had a nest, though I was unable to 

 find it. Comparatively few were seen along the unsheltered 

 western coast of Dall Island, but when we reached the head of 

 Boca de Quadra, we found them again in large numbers. Ou 

 the Chickamin River (June 17 to 28) the first broods of young 

 were seen. Later on, during July, flocks of young birds were 

 observed at Revillagigedo, Etolin, Wrangell and Zarembo 

 islands, and at Bradfield Canal on the mainland ; while both at 

 Mitkof Island and Thomas Bay (August 1 to 23) the species 

 was fairly common. On the Taku River, during September, 

 many American mergansers were seen flying along the stream, 

 usually in flocks of ten or twelve, each flock probably composed 

 of a single family. 



Several interesting peculiarities of the species were noted. 

 On Kuiu Island, April 28 (and on several subsequent occasions) 

 numerous individuals were observed feeding in a manner that 

 was entirely new to me as far as this group of ducks is concerned. 

 I was concealed in the shrubbery at the water's edge examining a 

 large flock of ducks for possible rarities, when a dozen or more 

 mergansers (both 31. americanus and M. serrafor) began swim- 

 ming back and forth but a very short distance from my blind. 

 They swam slowly, with neck outstretched, and with the bill 

 held just at the surface of the water, and at a slight angle, so 



