152 GAME BIBBS OF CALIFORNIA 



This reputation has largely been built up in eastern North America 

 where, by reason of its vegetable diet and the consequent fine flavor 

 of its flesh, it is very highly prized as a table bird. In California the 

 Canvasback is strictly a migrant, arriving during October and usually 

 departing by the end of March. The earliest fall record is from Stock- 

 ton, San Joaquin County, October 6, 1881 (Belding, MS) ; southern 

 California is usually reached about October 20 (Cooke, 1906, p. 44). 

 Observations made by E. W. Gifford (MS) over a term of years on the 

 arrival and departure of ducks about San Francisco Bay yielded the 

 following dates for Canvasbacks : 1903-1904, last seen April 4 ; 1904r- 

 1905, first seen December 8, last seen May 6; 1906-1907, first seen 

 December 26, last seen April 14; 1907-1908, first seen January 18, 

 last seen April 22 ; 1908-1909, first seen November 11, last seen April 

 3 ; 1909-1910, first seen, October 27, last seen, February 28. Most of 

 the Canvasbacks to be found in California are on the bays and coastal 

 marshes, from which places the bulk of the market supply, which is at 

 a maximum during November and December, is secured. 



The close similarity between the Canvasback and the Redhead 

 sometimes leads to confusion in distinguishing these two ducks. No 

 better worded diagnosis is known to us than that of Coues (1874, pp. 

 575-576) : 



Some persons experience difficulty in discriminating between the Canvas- 

 back and Eed-head, but there is no occasion for this, at least in the case of 

 males. In the Eed-head, the whole head is clear chestnut red, with coppery 

 or bronzy reflections, and the bill is clear pale grayish blue, with a dark tip. 

 In the Canvas-back, nearly all the head is obscured with blackish-brown, and 

 the bill is dusky throughout. There is also a marked difference in the shape 

 of the head and bill; in the Eed-head, the head is puffy and globose, sloping 

 abruptly down to the base of the bill; in the Canvas-back, the head is longer 

 and narrower, and slopes gradually down to the bill, which rises high on the 

 forehead [pi. 5 and figs. 20 and 21]. These distinctions of form hold with the 

 females, though less evident in that sex. In the Canvasback, moreover, the 

 back has much more light than dark color, instead of an equal amount, or 

 less, the fine black lines being very narrow and mostly broken up into minute dots. 



Although reported as breeding rarely in Oregon and Nevada 

 (Cooke, 1906, p. 43), there is no record of the nesting of this duck 

 within our own state. Brooks (1903, p. 278) records it as breeding 

 commonly in British Columbia. He describes the nests as being bulky 

 platforms of reeds, similar to those of Coots, and to be found gen- 

 erally on small swampy ponds, away from the larger lakes where the 

 males associate in flocks. Bent (1902, pp. 11-12), in North Dakota, 

 found the nests of Canvasbacks almost invariably located in isolated 

 clumps of reeds surrounded by water in large, deep sloughs. He 

 describes one nest as being built upon a bulky mass of wet dead reeds, 

 measuring eighteen by twenty inches in outside diameter, the rim 



