596 MOULT 



here we have briefly to consider the different phases which the act 

 of Moulting offers. 



As a general rule all kinds of Birds are subject to an annual 

 Moult, and this commonly begins immediately on the close of the 

 breeding -season, but, as will be presently explained, there are 

 some which undergo in addition a second or even a third partial 

 change of plumage, and it is possible that there may be others still 

 more exceptional : our information respecting these, however, is too 

 meagre to make it worth while saying anything here about them. 

 It must be acknowledged that with regard to the greatest number 

 of forms we can only judge by analogy, and though it may well be 

 that some interesting deviations from the general rule exist of 

 which we are altogether ignorant, yet when we consider that the 

 Ratitse, so far as observed, moult exactly in the same manner as 

 most other birds, 1 the uniformity of the annual change may be 

 almost taken for granted. 



It is not intended here to say more (cf. p. 248) of the way in 

 which a feather dies and a new one succeeds it, nor need we com- 

 pare the process of moulting with the analogous shedding of the 

 hair in Mammals or of the skin in Eeptiles, though the latter, in 

 the case of the flipper-like wings of the PENGUIN the scaly feathers 

 of which come off in flakes Mr. Bartlett (Proc. Zool. Soc. 1879, p. 

 6) has shewn to be remarkably close. Enough for our present 

 purpose to see that such renovation is required in Birds, nearly all 

 of which have to depend upon their quills for the means of loco- 

 motion and hence of livelihood. It is easy to understand that dur- 

 able as are the flight-feathers, they do not last for ever, and are 

 beside very subject to accidental breakage, the consequence of 

 which would be the crippling of the bird. 2 It is obviously to pro- 

 vide against what in most cases would be such a disaster as this last 

 that we find the remiges, or quill-feathers of the wings, to be nearly 

 always shed in pairs. They drop out not indeed absolutely at the 

 same moment, though this sometimes seems to happen, but within 

 a few days of each other, and, equilibrium being thus preserved, 

 the power of flight is but slightly deteriorated by their temporary 

 loss. The same may be observed in a less degree, since there is 

 less need of regularity, with the rest of the plumage, as a little 

 attention to any tame bird will shew, and the new feathers grow at 

 an almost equal rate. In the young of most species the original 

 quills are not shed during the first year, nor in the young of many 

 does there seem to be an entire moult during that time, but in the 



1 For the knowledge of this fact I am indebted to the vast experience of Mr. 

 Bartlett. 



2 By an ingenious but simple process known as "imping," which properly 

 means engrafting, and is described in almost every book on hawking, falconers 

 repair any broken flight-feather, and so restore the bird to its full power. 



