THE BUILDING OF A BIRD 31 



do not have any webs at all — only a slender shaft, as 

 fine as a hah\" 



'' Do feathers keep on growing all tl»e time, like my 

 hair? " asked Dodo. 



" No, my dear. i'hey stop growing as soon as they 

 are of the right size ; and yon will find yonr liair will 

 do the same, when it is long enough — though that 

 won't be for a good many years yet, little girl. When 

 the blood that has fed the growing feather is all dried 

 up, the feather ceases to grow. Then after a while 

 longer, when it has become ragged and worn, it gets 

 loose in the skin and drops out — as I am sorry to say 

 some of my hair is doing already. That is what Ave 

 call moulting.'^ 



" I know about that," interrupted Nat. " It's when 

 hens shed their feathers. But I didn't know that it 

 was moulting when people grow bald." 



" It is very much the same thing," said the Doctor, 

 " only we don't call it moulting when people lose their 

 hair. But there is this difference. Birds wear out 

 their feathers much faster than we do our hair, and 

 need a new suit at least once a year, sometimes oftener. 

 All young birds get their first new clothes when the 

 down is worn out. Old birds generally moult as soon 

 as they have reared their broods, w^hicli in this country 

 is late in summer or early in the fall. ^lany also moult 

 again the following spring, when they put on their wed- 

 ding dress ; and one of the curious tilings about this 

 change of plumage is, that the new feathers often come 

 out quite unlike those that were cast off. So a bird 

 may differ mucli in appearance at different seasons and 

 ages — in fact, most birds do. The male also differs 



