BUFFLE-HEAD 341 



and perhaps a few Scoters or Long-tailed Ducks, but they never really associate 

 closely with any of these. I have a good many times seen single birds with Hooded 

 Mergansers on autumn migration, for both species make their main flights at al- 

 most identical periods. 



On the breeding grounds careful observations made for me by Mr. Francis Harper 

 in the spring of 1920 showed that there was a marked competition between the Buffle- 

 head and the Golden-eye in the search for nest cavities. Indeed, a young Golden-eye 

 in down, collected on June 29, was being mothered by a female Buffle-head, which 

 suggests that even the broods become mixed either before or after hatching. 



"On July 2," writes Mr. Harper (MS.), "while watching the activity of several 

 Golden-eyes about a nest tree at our camp on the Riviere Coupee (Athabasca region) 

 I noticed four or five female Buffle-heads behaving in very much the same way on the 

 opposite side of the river. They circled about over the river and also rested on the 

 water near shore. Every once in a while a bird would fly into one of the large trees 

 on the bank and flutter about it, and others would flutter around nearby trees. . . . 

 On July 8 a female Buffle-head followed a female Golden-eye in fluttering before an 

 already occupied nest of the latter species in a tree at our camp, and when the 

 Golden-eye alighted on the river the Buffle-head promptly plumped down beside it." 

 Harper thought there was a good deal of contention between the two species as well 

 as between individuals of the same species, for good nesting-holes. 



Voice. The notes of this duck are merely feeble imitations of its louder- voiced 

 relative, the Golden-eye. I never have heard the little squeaky call of the male, which 

 must, I think, be very rarely uttered, like the Golden-eye's, in the spring only. The 

 female has at least two distinct calls, but even these are rarely heard, as the species 

 is exceptionally silent. The ordinary note is the guttural grrrk, grrrk, a croak like 

 the Golden-eye's, but much feebler. An entirely different note, which Harper often 

 heard when the females were flying about looking for nest-holes, was more like huk- 

 kuk-kuk-kuk, similar to the Golden-eye's under like conditions. The ordinary call, 

 mentioned above, is modified in various ways when used in piloting the young, or as 

 a danger signal. 



The trachea presents no peculiarities. It is somewhat flattened and about 4§ 

 inches (114 mm.) long. The tracheal box is rather simple in form, flattened, and not 

 markedly left-sided. On the dorsal aspect there are membranous windows separated 

 by a central keel and on the ventral surface the bronchi are united by a strong bony 

 ridge. 



Food. The strong-tasting flesh of this species, as of the Golden-eye, indicates a 

 predominance of animal food, both in summer and in winter. Nevertheless about 

 one third of the diet is vegetable. 



