FROM THE CRADLE TO THE GRAVE. 
83 
material necessary to their nourishment by the end of 
this operation; the supply of this nourishment always 
having been limited, they are thus rendered totally useless. 
As soon as the last brood of the season has been reared 
the shedding of the feathers commences: with some 
birds this takes place with great rapidity, with others 
slowly. The fresh feathers are reproduced in like pro¬ 
portion. With birds that fly, moulting is very regular in 
its action, inasmuch as two corresponding feathers are 
simultaneously cast, and then reproduced under the same 
conditions; take, for instance, the third quill-feather on 
either wing. Birds possessing extraordinary powers of 
flight, such as Eagles or Vultures, do not shed all the 
wing-feathers in one season, but only a few, and those 
generally in pairs, a second couple only dropping when 
the first feathers have almost arrived at their full growth. 
Many water-birds, on the contrary, however,—take for 
example the Geese and Ducks,—are totally incapable of 
flight during the moulting season, and therefore seek 
hiding-places wherein to undergo the process of moulting 
in safety. The wholesale way in which these birds change 
their plumage makes the time necessary for that opera¬ 
tion not more than a month, while in the case of the 
large birds of prey the moult extends over years before 
the whole plumage has become renewed. As a rule, birds 
of flight undergo fewer changes than marsh and water 
birds, many of which moult twice a year. 
Moulting commences earlier with the adult than with 
the younger birds, that is, those which have not yet left 
the nest; for these last, if they do not moult actually in 
the nest, do so soon after leaving it, casting, however, 
generally, only the smaller feathers, the pinion and tail- 
feathers being shed at a later period. In cases where the 
