200 BrnLLETIN 126, UNITED STATES NATIONAL, MUSEUM. 



ern surface boat or battery, an ingenious contrivance from which 

 more canvasbacks are shot than by any other method. It consists 

 of a stout wooden box, just long enough and deep enough to efl'ect- 

 ually conceal a man while lying down, surrounded by a broad wooden 

 platform, attached to its upper edge; the platform is also surrounded 

 with frames covered with canvas; it is so constructed and ballasted 

 that the platform floats flush with the surface of the water and the 

 box is entirely below it; the platform is constantly awash, but the 

 water is kept out of the box by projecting flanges. The battery is 

 towed out to the shooting grounds and anchored with 200 or more 

 wooden decoys anchored around it. The gunner is entirely out of 

 sight, except from overhead, as he lies flat in the bottom of the box 

 until the birds are near enough, when he rises and shoots. An 

 assistant is needed with a sailboat, launch, or skiff to pick up the 

 birds. 



When the canvasbacks first come in the fall, they gather in large 

 numbers in the salt waters of Chesapeake Bay. During November 

 they come down into the fresh waters of Back Bay, Virginia, and 

 Currituck Sound, North Carolina, their favorite winter resorts. Here 

 they feed on the roots and seeds of the foxtail grass which grows 

 abundantly in these bays, but will not grow in salt water. The growth 

 of this excellent duck food, on which the numerous duck clubs largely 

 depend for their good shooting, is being much injured by carp and 

 by the increasing abundance of swans; both of these species root up 

 or trample down this grass so extensively that the feeding grounds 

 for ducks are seriously injured. An open season on swans might 

 reduce their numbers and improve the duck shooting. The canvas- 

 backs, like the redheads, will feed in the bays all day, if not disturbed, 

 but usually large flocks, or flocks of flocks, may be seen flying out to 

 sea in the morning and back again at night. 



Winter. — The canvasback is a late migrant and often lingers in the 

 vicinity of the Great Lakes until driven farther south by the 

 freezing of its favorite lakes and ponds, which sometimes proves dis- 

 astrous. Mr. Elon H. Eaton (1910) says, of its occurrence in the 

 central lake region of New York: 



The winters of 1897-98 and the three following winters were remarkable for the 

 large flocks of canvasbacks which appeared about the 1st of December on these waters 

 and remained until early in March. On Canandaigua Lake a flock of nearly 1,000 

 canvasbacks passed a large part of the winter, and on Keuka Lake flocks of 200 birds 

 were frequently seen. In February, 1899, many of these ducks were killed on Canan- 

 daigua Lake about the air holes which remained open. Most of those killed were in 

 poor flesh and some were picked up on the ice in a starving condition. 



The freezing of Cayuga Lake in February, 1912, caused the death 

 of many canvasbacks and other ducks by starvation; I quote from 

 Mr. Alvin R, Cahn's (1912) interesting paper on the subject as follows: 



