OANVASS-BACK DUCK. 221 



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 Avind rows. Wherever this plant grows in 

 abundance, the canvass-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 particular 

 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 abundance of their favourite food, that, towards 

 the beginning of November, they are in pretty good 

 order. They are excellent divers, and swim with great 

 speed and agility. They sometimes assemble in such 

 multitudes as to cover several acres of the river, and, 

 when they rise suddenly, produce a noise resembling 

 thunder. They float about these shoals, diving and 

 tearing up the grass by the roots, which is the only 

 part they eat. They are extremely shy, and can rarely 

 be approached, unless by stratagem. When wounded 

 in the wing, they dive to such prodigious distances, and 

 with such rapidity, continuing it so perseveringly, and 

 with such cunning and active vigour, as almost always 

 to render the pursuit hopeless. From the great demand 

 for these ducks, and the high price they uniformly bring 

 in market, various modes are practised to get within 

 gunshot of them. The most successful way is said to 

 be, decoying them to the shore by means of a dog, while 

 the gunner lies closely concealed in a proper situation. 

 The dog, if properly trained, plays backwards and 



