282 NYROCA AFFINIS 



Wetmore (1920) is of the opinion that copulation may take place under water, a 

 point of some interest that would bear further observation among the diving ducks 

 as a whole. 



Major Brooks has called my attention to a lump, the size of a hickory nut, which 

 appears and travels upward, disappearing before it reaches the throat. There seems 

 to be some sort of throat inflation in the display of nearly all our common diving 

 ducks. 



The majority of the breeding dates are late, certainly later than those of the 

 Canvas-back, Red-head or Ring-necked Duck. Nests in late May or early June are 

 exceptional in most parts of the range, while June 15 to mid- July is the chief laying 

 period. May 28 seems to be the earliest date recorded, and there is one other May 

 date (Job, 1899; Bent, 1901-02, 1907; J. and J. M. Macoun, 1909; Ferry, 1910; 

 A. Wolfe, in litt.; Harper, MS.). 



In favorite localities many individuals nest in close proximity to each other, so as 

 almost to form a colony. Islands in lakes and the grassy edges of lakes are the loca- 

 tions they prefer. The situations chosen are very different from those usually se- 

 lected by the Red-head, Canvas-back and Ruddy. The nests are nearly all placed 

 on dry ground, usually less, and never more than fifty yards from the water (Bent, 

 1901-02). Occasionally nests are found on dry tussocks surrounded by water 

 (Baird, Brewer and Ridgway, 1884), and Harper (MS.) found two or three nests on 

 floating bogs among cat-tail and sedge, only a few inches above the surface of the 

 water and close to the edge of it. In the short prairie-grass the nests are often poorly 

 concealed, and at some little distance from the water. 



The nest itself is very unpretentious, consisting only of a hollow scooped in the 

 ground lined with a little sedge or grass and, late in the laying period, with an abun- 

 dant supply of dark, almost black down, and an occasional light feather. 



Judging from the size of the clutch alone this species is a very prolific one. Nests 

 with nine to fifteen eggs are not uncommon, and the average, in some places at least, 

 is ten, in other places about nine. Very few nests are found with so few as six or 

 seven eggs, so that in respect to the size of the clutch this species differs considerably 

 from the Greater Scaup. 



Mr. A. Wolfe (in litt.) has found Lesser Scaups laying in a Red-head's nest and he 

 once found an extraordinary pile of twenty-six Little Scaup eggs, the work no doubt 

 of several females. He took some of these eggs and tried to hatch them, but they did 

 not develop well. Piles of eggs like this are occasionally found deposited by other 

 species of ducks and it would be interesting to know whether they are apt to be in- 

 fertile. 



Their habit of laying eggs in the nests of other ducks has already been mentioned 

 under Association. 



The eggs are similar in color to those of the Greater Scaup, being pale grayish with 



