204 OBSERVATIONS ON THE CHANGES OP 



served, that in caged birds, excluded from the full influence of sun, air 

 and suitable food, the period may be extended, but not accelerated. 



The above instance may suffice to show the process which nature 

 pursues in effecting the changes of plumage, from the young to the 

 adult state, in land birds. I shall, therefore, omit adding the notes I 

 had prepared on several others : particularly on those of Polyhorus vul- 

 garis, Carracara Eagle, from Florida, a pair of which I have now in 

 confinement ; Falco borealis, Red Tailed Hawk ; Picus trylhroceplia- 

 lus, Red Headed Woodpecker ; Fringilla cardinalis, Red Bird ; Tana- 

 gra rubra, and sestiva, Scarlet Tanager, and Summer Red Bird; Co- 

 lurnba leucocephala, White Crowned Pigeon. &c. In all of them, 

 however, there is a striking uniformity, the changes being effected 

 during the space of a year, and in most of them the feathers become 

 gradually brighter immediately after the moult. 



I shall now proceed to note a few observations on those water birds 

 that are subject to striking variations in plumage, from the young to 

 the adult state, which will prove that nature, although varying in some 

 particulars in some of the species, is still subject to the same general 

 laws. 



Grus Americana, Whooping Crane. The young of this bird is of a 

 brownish ash colour, and at a year old is still one fourth smaller than 

 the adult bird. In this state it has been considered by all our writers 

 on American ornithology, with the exception of Audubon, as a distinct 

 species. 



Grus Canadensis, the Canada Crane. Dr Richardson, who found 

 its eggs (which were smaller than those of the Whooping Crane) in 

 the polar regions, is also under the impression that it is a distinct spe- 

 cies. It will be recollected, however, that all our birds, as far as we 

 are acquainted with their histories, breed at a year old, even before 

 they have attained their full plumage ; and that young birds lay smaller 

 eggs than old. How long a time the Whooping Crane requires to ar- 

 rive at full maturity, I have had no means of ascertaining. I however 

 had an opportunity of witnessing the change of colour in a pair of this 

 species, which convinced me that the Canada Crane was the young of 

 the Whooping Crane. The birds were obtained, it was said, from 

 Florida, in what manner I was not informed, and were represented as 



