80 
BIRD-LIFE. 
long time, which is, perhaps, only reached by the few. 
With the larger birds, especially the Eagle tribe, many 
years must pass away ere the point is attained, when the 
young can be said to have reached maturity. 
A bird’s age is determined with greater ease than that 
of any other animal, by help of the plumage. Perfect as 
it may appear in the newly and fully fledged bird, it is 
still in truth but the dress of childhood or of youth. 
This dress, however, can never vie with the plumage of 
the parent bird, though the tints and shades may seem 
to be identical; still the careful observer will remark that 
beauty and the true burnished polish only occurs in full 
perfection with the mature bird. With many birds we 
have hitherto been unable to determine with any degree 
of certainty how many years they wear the dress of their 
youth. The nest or first plumage is soon cast aside, and 
with some species—for instance, the Golden Oriole—it is 
abandoned before the young quit the nest; on the con¬ 
trary, the next dress lasts at least half a year with all 
birds, and in most cases passes through many inter¬ 
mediate stages ere it attains the full plumage of an 
old bird, and this again seems to get brighter and 
more beautiful with each succeeding year. Science dis¬ 
tinguishes the different colorations of the plumage with 
the greatest exactitude in order to determine with cer¬ 
tainty the age of well-known birds and to assist in 
making an approximate estimate of that of those less 
known to us. 
The plumage of many young birds bears no resem¬ 
blance whatever to that of the mature specimen; others, 
again, are like that of the adult female, which, as we 
know, is often coloured and marked quite differently 
from the aged male; lastly, there are others, though 
