!86 DUCKS. 



FAMILY L 

 THE DUCKS. ANATID^. 



'General Characteristics. — Bill generally depressed, broad, and always laminated 

 on the sides, the lamination being more prominent in some species than in others. 



The birds belonging to this family, of which the Geese and 

 Ducks are familiar examples, are easily distinguished from all the 

 rest of their Order by the peculiar structure of their bill,=i= which 

 is broad, and furnished with a covering of soft skin ; the edges of 

 both mandibles, moreover, exhibit a series of fine tooth-like 

 lamclLx, or plates, which interlock when the mandibles are nearly 

 closed, so as to form a sort of strainer. The feet are well developed, 

 and the anterior toes are united by an ample web. The hinder 

 toe is small, free, and raised more or less on the back of the tarsus. 

 The wings are tolerably large and powerful, enabling the birds, 

 notwithstanding their bulky and rather heavy bodies, to fly with 

 considerable ease and rapidity; many of them, indeed, are migra- 

 tory, and perform long journeys to and from their breeding-places, 

 often at a considerable elevation. They are generally gregarious, 

 and most of them frequent fresh water, although they are often 

 seen on the sea-shore in the winter season. Their food consists 

 chiefly of worms, aquatic insects, and mollusca, which they obtain 

 by straining the mud and water through the fine lamella; of their 

 bills. For this purpose they have their tongues very largely 

 developed, soft, and fleshy ; and when we consider the particular 

 use that the duck makes of this organ, we shall perceive that it 

 is endowed with great and unusual sensibility. The duck, unlike 

 other birds, discriminates its food, not by sight or by smell, but 

 by the touch of its tongue. It thrusts its bill into the mud just 

 as a fisherman casts his net into the sea, and brings up whatever 

 it contains ; from this mouthful of stuff it selects, by the tongue 

 alone, what is good for food, and everything else is rejected. The 

 gizzard of the Anatidai is muscular, and lined with a tough skin, 

 so as to be able to grind down the substances on which they feed. 

 The framework of the body of the natatorial birds is differently 

 constructed from that of the terrestrial Orders. In the aquatic 

 tribes, the breast-bone and ribs extend along the entire length of 

 the thorax and abdomen, and thus that part of them which is in 



* See "Animal Creation," page 358. 



