DIAGNOSES OF FAMILIES AND 

 GENERA 



THE WATER-FOWL 



Class Aves. Older Anseres. The Lamellirostral Swimmers. (Swim- 

 ming birds having toothlike serrations or lamellae on the bill.) Only 

 one family in order : the Anatida — ducks, geese, and swans. 



Family Anatidae. Swimming birds usually of large size with short tails. 

 •Wings of moderate length, strong and pointed, giving vigorous and 

 whistling flight. Bill covered with a leathery integument, with a hard 

 nail at the tip and usually broad and flat. Short legs with the tibia 

 almost buried in the feathers. Tarsus flattened. Anterior toes webbed ; 

 hind toe always present but usually small. Prascocial young. There 

 are five subfamilies found in North America — Mergince, Anatina, 

 Fuligulince, Anserirue, Cygnina. 



Subfamily Merginae. The Mergansers. Type : Neck shorter than body; 

 tarsus shorter than middlfc toe without claw. Bill narrow, nearly cylin- 

 drical, long, with hooked nail and toothlike serrations on cutting 

 edge of upper mandible ; no lamellae on sides of lower mandible. 

 Lores feathered. Tarsus with transverse scales in front; hind toe 

 with a lobe. Sexes unlike. 



This subfamily contains three genera — Merganser, Lophodytes, 

 and Mergus — and about nine species, of which most belong to the 

 Northern hemisphere. They are birds of handsome plumage, fre- 

 quent both fresh and salt water, feed chiefly on fish, which renders 

 their flesh unpalatable, and some of them nest in hollow trees. 



Generic Types. Merganser. Length of bill three times its depth at base. 

 Bill longer than head and than tarsus with very conspicuous toothlike 

 serrations on both mandibles, which are inclined strongly backward. 

 Head with a slight and pointed occipital crest. Tarsus about two-thirds 

 as long as middle toe with claw. Tail about half as long as wing. 

 Bill reddish. Two species of genus are found in North America. 



Lophodytes. Length of bill three times its depth at base. Bill 

 shorter than head but longer than tarsus, with serrations on mandibles, 



S6S 



