CANVAS-BACK 



241 



are not particularly early migrants but are usually well on their way 

 in the latter part of March and April, and are on their breeding grounds 

 before the beginning of May. Although the winter range extends to 

 northern South America, large numbers remain in the Southern States 

 and on the southern Atlantic and Pacific coasts, where they prefer to 

 feed in the inland marshes, ponds, swamps, and rice fields. 



Canvas-Back 



Nyroca valisineria 

 (ni-ro-ka, val-is-i-ner-i-a) 



Colour Plates Nos. 16 and 17. Downy Young No. 34. 



SCIENTIFIC NAME 



Nyroca, Latinized form of the Russian word Nirok or Nyrok, meaning a diving 

 duck; valisineria, from Vallisneria spiralis, the wild celery plant, so called after 

 Antonio Vallisneri (1661-1730) an Italian naturalist and Professor of Medicine at 

 the University of Padua. 



COLLOQUIAL NAMES 



IN GENERAL USE: Canvas; can; canny. IN LOCAL USE: Bullneck; canard cheval 

 (horse duck); grey duck; hickory-quaker; horse-duck; red-headed bullneck; shel- 

 drake; whiteback. 



DESCRIPTION 



ADULT MALE. WINTER PLUMAGE: Head and neck, reddish chestnut, dusky 

 on crown, before eyes and on throat; bill, blackish or greenish black, as long 

 as head, three times as long as its greatest width; eye, red. (Many immature 



birds have the eye clear yellow. Body. Chest and 

 foreback, brownish black; back and scapulars, 

 white, finely vermiculated with dusky; rump, 

 brownish black; breast, white; sides and belly, 

 white, very faintly vermiculated with dusky; jeet, 

 greyish blue to yellowish blue, webs, dusky. 

 Tail, brownish slate; upper and under coverts, 

 brownish black. Wings. All coverts, brownish 

 grey, vermiculated with white; primaries, brown- 

 ish grey, darker on tips and on outer webs, 

 sometimes flecked with white near tips of inner 

 primaries; secondaries, with pearl-grey speculum 

 shading into white bar behind, outer webs of 

 inner secondaries with black margins; tertials, 

 whitish, vermiculated with dusky; lining, white 

 and pale grey; axillars, white. (In extreme cases 

 the tertials, all wing-coverts, and most of the 

 speculum are frosted and vermiculated w r ith 

 white speckling, which is present even on the 

 tips of the primaries and primary coverts.) 



FIG. 45. Above, Redhead. 

 Below, Canvas-back. 



