BUFFLE-HEAD 343 



vicinity of Fort Resolution eggs have been taken on May 19 and on the upper 

 Yukon on May 8 (U.S. Biological Survey; Baird, Brewer and Ridgway, 1884). 

 About the Athabasca delta Harper (MS.) saw the first young on June 29, but they 

 were not plentiful until a good deal later, about the middle of July. 



The typical nesting site is the hole of the Golden-winged or Red-shafted Wood- 

 pecker at moderate heights (five to twenty feet) in any hollow tree. The entrance to 

 these holes may be surprisingly small and is usually less than three and one fourth 

 inches in diameter (A. Brooks, 1903) ; one nest opening was only 3| inches in diameter 

 (Brooks, in litt.). One or two observers have spoken of nests in burrows in banks or 

 on the ground. Possibly these do occur in treeless areas, but at any rate they are 

 very exceptional. It is well to remember that in placing artificial boxes for any of our 

 tree-nesting ducks the cavity should be only just large enough to admit the female. 

 The boxes ought to be rather deep, too, and by no means should they have ventila- 

 tion holes in the back, as I think some people have recommended. These hole- 

 nesting ducks like an absolutely dark spot to incubate in when they can get it. 



Out of many clutches which Allan Brooks has taken in British Columbia he col- 

 lected several eggs which he believes were cracked in the oviduct of the females as 

 they entered or left an opening a little too small for them. Similar cracks have been 

 found in eggs of Barrow's Golden-eye and the Carolina Duck. 



The clutch varies in size from five or six to ten, but it is so common for several 

 birds to compete for one site and to take care of each other's young that it is very 

 hard to strike an average. A. Brooks (1903) puts the average at eight. He describes 

 the eggs as old ivory in color, without any tinge of green. They average 50.5 by 36.5 

 mm., the maximum and minimum lengths being 55 and 44.5, and the maximum and 

 minimum widths 38 and 33.5 (Grinnell, Bryant and Storer, 1918; Hartert, 1920a). 

 The nest-down is similar to that of the Golden-eye, of a dirty white color. The 

 female is a very close sitter. Brooks tells of their sitting on the eggs till the hole 

 was sawed out. In most cases, he said, " I had to lift the bird and throw her up in the 

 air, when she would make a bee-line for the nearest lake, where her mate would be 

 slowly swimming up and down unconscious of the violation of his home." 



I do not think the incubation period has been accurately determined. Mr. D. H. 

 Bendick of Leduc, Alberta, has written to me about his experiences in rearing these 

 ducks from wild-gathered eggs and he says that he has hatched them (under hens) 

 in twenty-one and twenty-two days. 



The male probably stays about near the nest rather longer than in some other 

 species. At least he is often seen near the nest while the female is incubating. How- 

 ever, he takes no interest in the brood and is never seen with them. The number of 

 young with a female is very irregular, from two to nine, and once Harper found a 

 female with only one young which proved to be a downy Golden -eye! 



On July 15, Harper wrote, "I found a female with nine downy young ones in a 



