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



because they are partial to salt water, many 

 of the species occur in large numbers on 

 the interior lakes, rivers, and marshes. Their 

 food consists of mollusks, small fish, and 

 crustaceans, as well as the roots of aquatic 

 plants and seeds. Their nests are usually 

 placed on the ground or among rocks, al- 

 though a few species, such as the Golden-eye, BufHe Head, etc., lay 

 their eggs in hollow trees. 



Genus MARILA Oken. 



51. Marila americana (Eyton). 

 Redhead. 



Aythya americana (Eyt.), A. O. U. Check List, 1895, p. 52. 

 Local name: Redhead Duck. 



Distr.: North America, breeding from Maine, northern Michigan, 

 Wisconsin, and California northward. Winters in numbers from 

 Chesapeake Bay to Florida and along the Gulf coast to Texas, casual 

 as far south as Mexico and Jamaica. 



Adult male: Head and neck, brownish chestnut; lower neck and 

 upper breast, blackish; back, apparently grayish, being white pencilled 



with fine, wavy lines of 

 black; speculum, gray- 

 ish; upper feathers 

 edged with black, the 

 rest narrowly tipped 

 with white. 



Length, 21; wing, 

 8.40; tarsus, 1.60; bill, 

 2.20. 



Adult female: Bill, 

 bluish, showing an in- 

 distinct bar near the end; head and neck, reddish brown, palest on the 

 sides of the head, becoming ashy on the sides of the head; upper 

 throat, white; breast and sides, brownish; belly, white; under tail 

 coverts and lower belly, sometimes washed with pale brownish. 

 Length, 20.50; wing, 8.30; tarsus, 1.60; bill, 2.20. 

 A common species in Illinois and Wisconsin during the migrations 

 and, according to Kumlien and Hollister, a few pairs still breed in 

 Wisconsin in the marshes about Lake Koshkonong. 



The nest is in a marsh, made loosely of grass and usually lined 



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