THE PEREGRINE FALCON. 117 



doubtful and disputed species of this intricate tribe of 

 birds. 



It is not surprisino- that different ages of this bird 

 should have been regarded as distinct species by those 

 who had no opportunity of watching the progress of 

 its growth. At every successive change the plumage 

 undergoes a fresh modification, not in colour alone, but 

 even in the distribution of the markings. It is only at 

 the third or fourth moulting that it assumes any thing 

 like permanence of character; and even after that time 

 it gradually becomes lighter as the bird advances in 

 age. In the first year it is generally of a light brown 

 on the upper parts, with an ash-coloured tinge on the 

 middle of the feathers. Its head and neck are whitish, 

 with a tinge of red and numerous dark brown spots; 

 its throat and under parts dirty white, with longitudinal 

 spots of brown ; its iris brown ; its cere bluish horn- 

 colour ; and its legs yellow. As it advances in age the 

 upper parts become grayish brown, with lighter trans- 

 verse bands ; and the longitudinal markings of the 

 under surface are converted into transverse bars. This 

 conversion takes place in a gradual manner, and affords 

 a certain means of distinguishing the young from the 

 adult bird, not only in the present species, but through- 

 out the whole of the Hawk and Falcon tribes. At the 

 same time there is developed in the Peregrine Falcon a 

 character which is not very distinct in the young bird, 

 and is somewhat more fiiintly marked ni the female 

 than in the male, but which may be regarded as one of 

 the best diagnostics of the species. It consists in a 

 broad black streak passing downwards obliquely over 

 the cheeks from the inner angle of each eye, and giving 

 to the bird a very peculiar expression of countenance. 

 When perfectly full grown the beak is lead-coloured 

 witli a darker tip : the cere has a o;i'eenish tinge : and 



