NATATORES. 235 



which were shot on Kingsbury Reservoir in severe 

 weather ; and a local keeper states that many years 

 ago, before this sheet of water was so much fre- 

 quented, a few ' Black Ducks ' generally made their 

 appearance every winter. 



POCHARD or DUN BIRD, Anas ferina. A winter 

 visitant, varying much in numbers in different years. 

 It is a wary and suspicious bird, and on this account, 

 as well as through its expertness in diving back 

 through the pipe, it is rarely taken in a decoy. Like 

 the Wild Duck and Teal, it feeds chiefly at night, its 

 diet consisting of the seeds of aquatic plants and other 

 vegetable matter, varied with different species of fresh- 

 water shells.* The note is a low whistle, except when 

 the birds are suddenly sprung, when the} T quack like 

 the Wild Duck. Dun Birds fly very rapidly, with a 

 noisy twitter of the wing, and may be known by the 

 shortness of their pinions and their heavy-looking 

 bodies, and especially by their filing in a closely- 

 packed lump, and not in line or figure as Widgeon 

 and Duck. 



FERRUGINOUS or CASTANEOUS DUCK, Anas nyroca. 

 This bird, sometimes called the " W 7 hiteeyed Po- 

 chard," is a rare winter visitant from the East. It 

 somewhat resembles the Pochard in appearance, but 

 may be distinguished by its smaller size, dark brown 



* Some bivalves belonging to the genus Pisidium recog- 

 nized. 



