THE MOULTING OF BIRDS. 173 



The young of the birds in this division advance to 

 maturity as follows. The young Swifts are hatched 

 naked and blind, and their first plumage is similar to 

 that of their parents, but the pale margins to the 

 feathers are more clearly defined and suffused with buff. 

 After their first spring moult, the adult plumage is 

 practically completed. In the Birds of Prey, the young, 

 as nestlings, are more or less covered with down. Their 

 first and successive stages of plumage vary so widely in 

 individual species, and the time that elapses ere they 

 reach maturity is in many instances so long, that it is 

 impossible to give details of these birds' advance to 

 maturity within the narrow limits of our space. In the 

 true Falcons, the young in first plumage differ con- 

 siderably from their parents in colour, but moult into 

 adult dress during the summer following the one in 

 which they were hatched. In the Osprey, the young 

 birds resemble the female in autumn dress, but the 

 males do not obtain their adult plumage until they are 

 several years old. The Eagles mature much more 

 slowly, the White-tailed Eagle, it is believed, taking six 

 or seven years to do so. In the Honey Buzzard and 

 the Rough-legged Buzzard, young birds have the 

 markings on the under parts in the form of streaks 

 instead of bars. Young Sparrowhawks and Goshawks 

 in first plumage resemble the adult female, but the 

 males (at all ages) are much smaller in size a pecu- 



