364 NATURE STUDY REVIEW [16:9— Dec, 1920 



Name and Recognition Characters 



The scientific name of the canvasback is Marila vallisineria 

 named after Vallisineria spiralis, wild celery, upon which it feeds. 

 Besides being known as the canvasback this duck has been called 

 ♦"white back," "bullneck." and in the vicinity of New Orleans 

 " canard cheval or horse duck." 



This species is often mistaken for the redhead to which it bears 

 a resemblance. Therefore in learning to distinguish it from the 

 redhead we will also learn its most characteristic marks. The 

 males can be told apart as follows : i . The chin and crown of the 

 canvasback has a blackish tinge while the same parts of the red- 

 head are like the rest of his head, rufus. 2 . The lower back and the 

 wing coverts of the canvasback are finely barred with wavy lines 

 of black and white the black and white lines being of different 

 widths, the white ones wider. On the redhead the lines are the 

 same width. 3. The bill of the canvasback is over two inches long 

 and that of the redhead is under two inches. 4. The head and neck 

 of the canvasback are more brown than red whereas the same parts 

 of the redhead are red. The female canvasback has a grayish 

 brown back barred with wavy white lines. These lines are absent 

 in the case of the redhead. 



Range and Breeding Habits 



The canvasback is found generally throughout North America. 

 It breeds in the central British Columbia, Fort Yukon, south west 

 Keewatin south to Oregon, northern Nevada, Colorado, Nebraska, 

 and southern Minnesota. Breeding early in the season, nesting 

 in the latter part of June, it associates with the scaups, the red- 

 heads, and the ruddy ducks. The nests are large and bulky, built 

 upon a mass of reeds which is usually surrounded by water about 

 knee deep. The nest itself is made of dead weeds, measuring 

 eighteen inches by twenty inches outside diameter and the rim is 

 built up about six inches from the water. The inner cavity is 

 about four inches deep, lined with small pieces of dead reed and 

 gray down taken from the breast of the female bird. The whole 

 is so well concelaed as to be invisible from the outside. The eggs 

 six to ten in a nest vary in color from grayish olive to greenish 

 drab. Often the eggs of the redhead are found in the nest of the 

 canvasback. 



