CANVASS-BACKED DUCK, 431 



sistence, they arrive about the middle of October seawards 

 on the coast of the United States. A few at this time visit 

 the Hudson and the Delaware, but the great body of emi- 

 grants take up their quarters in the Bay of Chesapeake, and 

 in the numerous estuaries and principal rivers which empty 

 into it ; particularly the Susquehannah, the Patapsco, Poto- 

 mac and James' rivers. They also frequent the sounds 

 and bays of North Carolina, and are abundant in the 

 river Neuse, in the vicinity of Newbern, and probably 

 in most of the other southern waters to the coast of the 

 Gulf of Mexico, being seen in winter in the mild cli- 

 mate of New Orleans.* In these different sections of the 

 Union they are known by the various names of Canvass- 

 Backs, White-Backs, and Sheldrakes. In the depth of 

 winter, a few pairs, probably driven from the interior by 

 cold, arrive in Massachusetts Bay, in the vicinity of Cohas- 

 set and near Martha's Vineyard : these, as in the waters of 

 New York, are commonly associated with the Red-Head, or 

 Pochard, to which they have so near an affinity. Their 

 principal food, instead of the fresh-water plant Valisneria, 

 which is confined to so small a space, is, in fact, the differ- 

 ent kinds of Sea- Wrack, known here by the name of Eel- 

 grass, from its prodigious length, [Zoster a marina, and Rup- 

 jpia maritima.) These vegetables are found in nearly 

 every part of the Atlantic, growing like submerged fields 

 over all the muddy flats, shallow bays, estuaries, and inlets, 

 subject to the access of salt or brackish waters. They are 

 the marine pastures in which most of the Sea Ducks, no 

 less than the present, find at all times, except in severe 

 frosts, an ample supply of food. 



The Canvass Backs on their first arrival are generally 

 lean, but by the beginning of November, they become in 



* Mr. Ware, on the authority of Mr. C. Pickering, M. D. 



