322 Field Museum of Natural History — Zoology, Vol. IX. 



The Black Duck differs from the red-legged form in its being 

 somewhat smaller, and having the legs oliv?, and bill, not so yellow. 

 The sexes are similar. 



Length, about 21; wing, about 10.75; bill, 2.10. 



This species is at times fairly common during the migrations in 

 both Illinois and Wisconsin and a few remain to breed in both states. 

 The nest is on the ground. The eggs are 8 to 12, pale greenish 

 white or bluish white, and measure 2.45 x 1.80 inches. The note of 

 the male is something like ''Drake, drake, drake, drake," and also 

 " Shwipe," in a husky voice; the female, "quacks." 



" An uncommon migrant with the preceding and a very rare sum- 

 mer resident. * * * * One or two pairs nest each year on the 

 Calumet marshes. " (Nelson, Birds N. E. 111., 1876, p. 139.) 



Genus CHAULELASMUS Bonap. 



42. Chaulelasmus streperus (Linn.). 



Gadwall. 



Anas strepera Linn., A. O. U. Check List, 1895, p. 49. 



Local names: Gray Duck. Creek Duck. 



Distr.: Nearly cosmopolitan. In North America it breeds chiefly 

 from the northern United States (Nebraska, northern Wisconsin, 

 etc. ) to Hudson Bay and Manitoba. Ranges from Hudson Bay and 

 Lesser Slave Lake to the Gulf coast, Lower California, and southern 

 Mexico, Florida, and Cuba. 



Adult male: Top of head, brownish, finely streaked and mottled 

 with black and dark brown; neck and breast, mottled (black and 

 white), the feathers being black, having a central white mark; under 

 parts, white (sometimes grayish white); under tail coverts, black; 

 upper tail coverts and rump, black; speculum-, black and white; the 

 lesser wing coverts, chestnut; bill, black; feet, orange; axillars, white, 

 with white shafts. 



Length, 19.50; wing, 10; bill, 1.60. 



Adult female: Somewhat resembles the male, but has the under 

 wing coverts pure white, and usually little or no chestnut on the lesser 

 wing coverts. 



Length, 19; wing, 10.15; bill, 1.55. 



This species is common in Illinois and Wisconsin during the mi- 

 grations. It apparently does not breed in Illinois, but it still does 

 so in northern Wisconsin. The nest is placed on the ground and is 

 composed mostly of feathers and down. The eggs are 9 to 12, uni- 



