DUCKS, GEESE, AND SWANS 



57 



The redhead is so similar to the canvas-back as to be easily mis- 

 taken for it at a little distance, and in habits the resemblance is 

 equally close. Goss says that this deep water duck, though widely 

 distributed, is not so common on the Pacific slope as east of the 

 Rocky Mountains. It is usually found in flocks on the open water 

 associated with canvas-backs, and diving with them for its food, 

 which consists of various kinds of submarine and fresh water plants, 

 small mollusks. crustaceans, fish, frogs, and water newts. 



147. Aythya vallisneria ( Wils.). CANVAS-BACK. 



Bill three times as long- as wide. Adult male: head and neck rich 



chestnut brown, becoming- 

 dusky on crown and face ; 

 shoulders and chest black ; 

 sides and back light gray ; 

 belly white or grayish ; tail 

 and quills dark gray ; feath- 

 ers around base of tail black. 

 Adult female: plumage 

 mainly umber brown, becom- 

 ing whitish around face and 

 chin. Length: 20.00-23.50, 

 wing _ 8.75-9.25, bill 2.10-2.50. 



Distribution. Whole of 

 North America, breeding in 

 Colorado,Nevada, Minnesota, 

 and northward to Fort An- 

 derson and Fort Yukon. 



Nest. Usually in reeds, 

 grass, or rushes, in shallow 

 water, a bulky mass of grass 

 stems lined with down. Eggs: 

 7 to 8, pale olive green. 



In its breeding range the 

 canvas-back is largely a bird of the northern interior, while in winter 

 it is found mainly in the bays and estuaries of the southern coasts, 

 where it is attracted by its favorite food, the stems and bulbs of wild 

 celery or eel grass, Vallisneria. While feeding on this plant the 

 canvas-backs become fat and so delicately flavored as to outrank all 

 other ducks in quality and market price. Hunted wherever they 

 go, they have learned that existence depends on eternal vigilance, 

 and so keep out in open water as far from shore as their feeding 

 grounds will allow. VERNOX BAILEY. 



Subgenus Fuligula. 



148. Aythya marila (Linn.}. SCAUP DUCK: BLUE-BILL. 



Bill short and wide, bluish with black tip. Male in breeding plumage : 

 head black, glossed with green ; shoulders, rump, and chest black ; belly 

 white, margined along sides with light grayish ; crissnm black. Post- 



