How to Understand the Birds [ 27 



between which there are bare areas. However, the overlapping 

 of feathers of the adjacent tracts keeps the skin completely covered 

 in healthy birds. You may see a chicken looking "half-naked" as 

 the result of arrested feather development. This never happens 

 to wild birds unless they are diseased. 



Most birds molt only once a year, but the brilliantly colored 

 males that have dull winter coats must change again to regain 

 their beauty in the spring. Hence such birds as the scarlet tanager 

 and the goldfinch undergo a spring (prenuptial) as well as fall 

 (postnuptial) molt. The spring molt is usually not complete, how' 

 ever; the wing and tail feathers serve both plumages. 



Some birds change appearance between winter and spring 

 without undergoing a second molt. They do so merely by "feather 

 wear"; that is, the feather tips which have given the general tone 

 to the winter plumage wear away and expose the bright colors of 

 the breeding plumage. The robin is a notable example. His breast 

 becomes redder as spring advances because the gray feather tips 

 are wearing off. In other birds yellow, brown, and gray most 

 frequently edge the feathers in winter plumage. As these colors 

 disappear, black, brown, or red is revealed. 



Molting consumes energy. While it is growing a new set of 

 feathers, a bird neither sings nor fights, staying in seclusion except 

 when it must seek food. It is for this reason, rather than because 

 of an early departure for southern climes, that you see few birds 

 in late August and early September. As soon as the birds have 

 completed their molting they regain their vitality and are ready 

 to migrate or to face the rigors of a northern winter. 



The Versatile Beak 



The child who is always asking "Why?" will be fascinated by 

 the endless variety of bird beaks. In almost every case, beak 

 formation gives us the clue to a bird's eating habits, diet and 

 even its surroundings. The duck, for example, has a wide, flat 

 bill that equips it for feeding on water insects and plants. After 

 seizing food in its beak, the duck holds the food until the water 

 strains out of the sievelike edges. Given the same conditions, the 

 sharp, horny beak of the hen would be quite useless. The hen's 



