BIRDS OF KANSAS 141 



please the reader better than to quote from Wilson's inter- 

 esting description of its habits, wherein he says : 



" The Canvas-back Duck arrives in the United States 

 from the north about the middle of October; a few de- 

 scend to the Hudson and Delaware, but the greater body 

 of these birds resort to the numerous rivers belonging to 

 and in the neighborhood of the Chesapeake Bay, particu- 

 larly the Susquehanna, the Patapsco, Potomac and James 

 rivers, which appear to be their general winter rendezvous. 

 Beyond this to the south, I can find no certain account 

 of them. At the Susquehanna, they are called Canvas- 

 backs; on the Potomac, White-backs, and on the James 

 river, Shelldrakes. They are seldom found a great dis- 

 tance up any of these rivers, or even in the salt water bay ; 

 but in that particular part of the tide water where a cer- 

 tain grass-like plant grows, on the roots of which they 

 feed. This plant, which is said to be a species of the Val- 

 lisneria, 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 windrows. 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 Philadel- 

 phia, and in most of the rivers that fall into the Chesa- 



