86 
PLUMAGE WEAR 
swims or runs about in it shortly after hatching. In the Gallinse 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’ 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 can 
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 
