104 CANVAS-BACK DUCK. 



probable of the two, I have designated this as a new species, and 

 shall proceed to detail some particulars of its history. 



The Canvas-back Duck arrives in the United States from 

 the north about the middle of October, a few descend to the Hud- 

 son and Delaware, but the great body of these birds resort to the 

 numerous rivers belonging to and in the neighbourhood of the 

 Chesapeake Bay, particularly the Susquehannah, the Patapsco, 

 Potowmac, and James' rivers, which appear to be their general 

 winter rendezvous. Beyond this to the south, I can find no cer- 

 tain accounts of them. At the Susquehannah they are called Can- 

 vas'backsj on the Potowmac White-backs^ and on James' river 

 Sheldrakes, They are seldom found at a great distance up any of 

 these rivers, or even in the salt water bay ; but in that particular 

 part of tide water where a certain grass-like plant grows, on the 

 roots of which they feed. This plant, which is said to be a 

 species of Valisineria^ grows on fresh water shoals of from seven 

 to nine feet (but never where these are occasionally dry), in long 

 narrow grass-like blades of four or five feet in length ; the root is 

 white, and has some resemblance to small celery. This grass is 

 in many places so thick that a boat can with difficulty be rowed 

 through it, it so impedes the oars. The shores are lined with 

 large quantities of it torn up by the ducks, and drifted up by the 

 winds, lying like hay in wind rows. Wherever this plant grows 

 in abundance the Canvas-backs may be expected, either to pay 

 occasional visits or to make it their regular residence during the 

 winter. It occurs in some parts of the Hudson; in the Delaware 

 near Gloucester, a few miles below Philadelphia ; and in most of 

 the rivers that fall into the Chesapeake, to each of which particu- 

 lar places these ducks resort ; while in waters unprovided with 

 this nutritive plant they are altogether unknown. 



On the first arrival of these birds in the Susquehannah, near 

 Havre-de-Grace, they are generally lean ; but such is the abund- 

 ance of their favorite food, that towards the beginning of Novem- 



