SWANS, GEESE AND DUCKS 



Family Anatidae 



The Swans, Geese, and Ducks belong to the Family Anatidae. This 

 Family includes all web-footed swimming birds with lamellate bills. 



The Family comprises about 225 forms, distributed throughout the 

 world; 61 of these are found in North America, including 4 species (see 

 list below) that are more or less regular visitors to this continent. In 

 addition, 15 other species have been recorded as accidental or casual visi- 

 tors but their occurrence here has been so rare that they are not included 

 in this work (see list below). 



The Family Anatidae is characterized by the following general fea- 

 tures: 



(a) The bill is broad and flat (except in the Geese and Mergansers), 

 and lamellate, that is, fitted with lamellae, or tooth-like serrations along 

 the edges of both mandibles; the serrations on the upper and lower man- 

 dibles fit together and form a strainer which permits retention of food 

 particles and expulsion of water taken into the mouth; the serrations 

 vary in number and form in the different species; the bill has a soft, 

 leather-like, membranous covering, and is equipped with a "nail" or 

 hard spot at the tip of the upper mandible, usually bent over in the form 

 of a hook; the tongue is fleshy and, in some, provided with serrations or 

 papillae along the edges. 



(b) The foot has four toes; the three in front joined together by two 

 fully developed webs; the hind toe is small, somewhat elevated, and free. 



(c) The legs are short (except in the Tree Ducks, and placed far 

 apart, not so near the centre of the body as in the gulls, and not as far 

 back as in the Grebes (except in the Ruddy Duck group, in which they 

 are well to the rear); the legs are feathered nearly to the "ankle" joint; 

 the position and length of the legs give the birds a peculiar waddling gait. 



(d) The body is more or less flattened; the tail usually short (except 

 in the Ruddy Duck group); the wings moderately long; the neck usually 

 long; the surface plumage firm and dense, especially on the breast, which 

 has a copious underlay of down. 



(e) The majority nest on the ground, but some nest in hollow trees 

 and stumps; the eggs usually are numerous, oval in shape, and plain in 

 colour; the young are covered with down when first hatched and almost 

 immediately can walk and swim. 



(f) During the summer moult the flight-feathers are shed simulta- 

 neously and the birds become flightless for a while. (The flight-feathers 

 of most other birds, with the exception of such birds as Loons and 

 Grebes, are replaced gradually and the power of flight is not lost during 

 any moult.) 



(g) The birds of this Family are provided with an oil gland, the 

 ducts of which open terminally in a nipple-like elevation on the "pope's 

 nose" at the root of the tail; the gland secretes a greasy fluid which the 



