158 THE STRUCTURE AND LIFE OF BIRDS cuap. 
after being fed daily are left to pick up their own food, 
the moult is arrested. Bird fanciers hasten the moult 
by putting their victims in a dark and rather cold 
place. Pigeons, which do not pair, put off their moult,. 
and so are in splendid condition for flying. By some 
process at present not understood in Europe, the 
Japanese check’ the shedding of the tail feathers of 
Cock Chickens, and so produce the enormous growths 
(ten or twelve feet long) with which we are familiar. 
The Ptarmigan moults no less than three times in 
the year. After the nesting season he sheds many of 
his smaller feathers and becomes gray ; in autumn he 
moults again, and in winter is arrayed in white, with 
feathers on his legs supposed to be intended to 
prevent him from sinking into the snow. A partial 
moult in spring arrays him in his breeding plumage of 
black and gray-brown and white. The big wing- 
feathers are white at all seasons. The claws are 
shed in July and August, and have grown to their full 
length again before the bird puts on his winter dress. 
The moulting of birds in their first year presents 
great varieties. In most songsters it begins thirty or 
forty days after they have left the nest. Hawks and 
their allies keep their first plumage till next summer. 
Young Ducks first appear in the same dress as their 
parents in late autumn. Geese have only down feathers 
till six weeks old; after that appear feathers proper, 
which they shed between September and December. 
In their second autumn, like mature geese, they moult 
completely in the space of four weeks. A young bird 
of aquatic habits can afford to be content with a 
covering of down for a long time after his birth. A 
