No. 18. 



Aythya affinis. 



In appearance, excepting size, like No. 17 ; gloss about head, 

 however (when discernible), having more of a purplish than 

 greenish cast. 



" Length fifteen and a half to seventeen inches ; extent under 

 thirty inches." * 



Range, " North America in general ; breeding chiefly north 

 of the United States" (A. O. U. Check List). 



See No. 17 for names shared in common with this species, 

 but not repeated here. 



This, the LESSER SCAUP DUCK, though often found in com- 

 pany with preceding species, is certainly more partial to inland 

 water, or rivers, creeks, and ponds. I find it locally designated 

 as follows: 



In the vicinity of Lake St. Clair, RIVER BLUE-BILL; at 

 Chicago, LITTLE BLUE-BILL (adjectives "little" and "small" 

 being naturally more or less used in many localities by those 

 who recognize Nos. 17 and 18 as distinct); in Revised List of 

 Birds of Central New York, 1879, MARSH BLUE-BILL (given as 

 "local"); at Pleasantville, Atlantic Co., New Jersey, MUD BLUE- 

 BILL. 



At Stratford, Connecticut, and Seaford (Hempstead), L. L, 

 RIVER BROAD-BILL; at Shinnecock Bay, L. L, and Tucker- 



* Having quoted measurements of greater scaup, No. 17, 1 prefer to quote 

 these also, this time from Dr. Coues's Key, 1884. By comparing quotations, 

 and taking into account that the plumages are practically alike, it will be seen 

 that under certain conditions the two ducks are not easily separated. 



