86 PLUMAGE WEAR 



swims or runs about in i shortly after hatching. In tiie Gallkise the 

 wing-quills are large enough to permit of short flights while the body 

 of the chick is still in the downy plumage. They are lost at the suc- 

 ceeding postnatal molt, which is entire, new wing- and tail-feathers, 

 as well as body feathers, being acquired. 



Ptarmigan unmistakably demonstrate the need of a protective 

 coloration by undergoing only a limited instead of complete molt at 

 the close of the nesting season. It affects solely the upperparts and 

 breast, or exposed surfaces, and is obviously a transition plumage, of 

 neutral browns and grays, designed to prevent the acquisition of the 

 wholly white winter dress until the coming of snow, at which time a 

 complete molt follows and the bird becomes as white as its surround- 

 ings. 



Male Ducks have a not dissimilar supplementary or partial post- 

 nuptial molt which is apparently also acquired for protective pur- 

 poses. It affects chiefly the scapulars, head, neck and breast, and is 

 worn only while the bird is deprived of the power of flight through the 

 loss, in the postnuptial molt, of its wing-quills In this 'eclipse 7 plu- 

 mage, as it is called, the male resembles the female, but when the 

 new wing-quills are grown and the power of flight returns, this eclipse 

 plumage is shed and the male plumage regained. (See Plate V.) 



The simultaneous loss of the flight-feathers is common to swim- 

 ming birds which have a secondary means of locomotion in their natato- 

 rial powers, but with other birds the wing-quills are molted slowly and 

 symmetrically from the middle of the wing both inwardly and out- 

 wardly. As the old feathers are lost new ones grow, and the bird car 

 therefore fly during the whole period of feather renewal. 



In other feather tracts, also, normal molt follows an orderly sequence, 

 feather succeeding feather and plumage plumage throughout the life of 

 the individual. The minor variations of molt within the limits above 

 outlined for the Passeres are endless, but they can be considered 

 adequately only by treating of each species separately. For further 

 details the student is therefore referred to the succeeding descriptions 

 of plumage, and particularly to the papers of Dwight ('00) cited 

 beyond. 



Plumage Wear. Molt, wear and fading are the only processes by 

 which the color of a bird's- plumage is changed. The claim that a feather 

 may be repigmented, and that consequently a bird's plumage may 

 undergo radical changes in color without the growth of new feathers 

 and without the aid of wear and fading, has never been substantiated, 

 and by students of the development of the feather from germ to ma- 

 turity such a change is declared to be impossible. (See, especially, 

 Strong.) 



Striking changes are, however, effected by wear, chiefly of the tips 

 or margins. These differ in color from that of the base of the feather 

 which is wholly or in part concealed. The loss of these margins may 

 completely alter the Bird's appearance, as where the brown Snow 



