COLOUR IN BIRDS AND QUADRUPEDS. 199 



which theory is founded on nature and truth. Systems which we 

 adopt in haste, from an examination of a few isolated facts, without 

 awaiting the slow progress of time, are frequently obliged to be aban- 

 doned in after years. When Bonaparte wTote his long, spirited and 

 interesting article on Peale's Egret Heron, and framed his theory that 

 " the Egret Herons are entirely of a snowy whiteness, without any co- 

 loured markings on the plumage whatever," he could not have con- 

 ceived that the next student of nature who visited the spot where his 

 specimen was obtained, should discover that this identical species be- 

 came brown and rufous ; and thus compelling nature herself to scatter 

 his fine spun theory to the winds. 



It is proposed in this article to give such facts relating to the moult- 

 ing of birds and quadrupeds, as some experience has enabled me to 

 collect. Should this have a tendency to elicit further inquiry, on a 

 subject so interesting to naturalists, and lead to the study of the causes 

 of these wonderful changes, my object will be attained. 



1. Does the change of plumage in some birds arise from a change 

 of feathers, or from the feathers themselves assuming at one period a 

 different colour from that which they have at another? 



On this head the following observations were made. 



Falco leucocephalus. A pair of birds were sent to me in the spring 

 of 1830, taken from a nest in the neighbourhood of Beaufort, S. C, 

 two years before. The old birds having appeared unusually large, and 

 destitute of the white heads and tails of the Bald Eagle, the individual 

 who had preserved the young, sent them to me under an impression 

 that tliey were the long disputed Sea Eagle (F. alhicilld) of Europe. 

 Perceiving that they were the young of our F. leucocephalus^ and being 

 aw^are that some of these birds, when in confinement, required five 

 and six years before they attained their full plumage, I did not much 

 value these troublesome and expensive pets. On a closer examination, 

 however, I observed that the male had some of the feathers of his head 

 streaked with white, whilst the outer edges were bordered with brown. 

 I discovered also, when he spread out his tail, that some of the inner 

 portions of his feathers were broadly and irregularly patched with 

 white. I concluded that the important change I was desirous of wit- 

 nessing was in progress. The birds were therefore carefully fed and 

 VI. — 2 z 



