Feathers of Birds^ mdependent of Moulting* ^73 
ed the plumage of the adult bird. Upon examining the feathers 
of this bird, I found many of them which were party-coloured, 
the same individual feather retaining, in some parts, the colours 
of the bird during its jfirst months, and in other parts exhibit-^ 
ing those of the perfect bird,*” p. 525. Other facts of a similar 
kind are likewise recorded, as having been observed in the chaf- 
finch, sandpipers and gulls. 
In the valuable “ Memoir on the Birds of Greenland,*” by 
Captain Edward Sabine, which follows the communication of 
Mr Whitear in the volume, there is added, under the Alca alle, 
some very interesting information regarding the change of co- 
lour which its feathers undergo. The whole of the birds in 
the breeding season (the sexes being alike), had the under part 
of the neck an uniform sooty-black, terminating abruptly, and 
in an even line against the white of the belly : the young birds, 
which we saw in all stages from the egg, as soon as they were 
feathered, were marked exactly as the mature birds ; but in the 
third week of September, when we 'were on our passage down 
the American coasts every specimen, whether old or young, was 
observed to be in change ; and in the course of a few days, the 
entire feathers of the throat and cheeks, and of the under part 
of the neck, had become white,**** p. 537, I am the more pleas- 
ed with the details of the change of colour in the plumage of 
this bird, because my attention was first directed to the subject, 
ill consequence of comparing a specimen in its summer dress, 
which I received from that accomplished navigator Captain 
Scoresby, with those which I obtained in their winter and spring 
dress in Zetland. Montagu has indeed availed himself of the 
facts which I thus ascertained, in his supplement to the Orni- 
thological Dictionary, article Auk, Little, 1813, and other de- 
tails are given in the article Hybi:rnation, Edin. Encyc. vol. xi. 
p. 388. 1817. 
Neither Mr Whitear nor Captain Sabine have offered any. 
conjectures in illustration of the laws which regulate these 
changes of the colour in the plumage of birds, and of the pur- 
poses to which they are subservient in the animal economy. Ii^ 
the article Hybernation referred to, I arrived at the following- 
conclusions : 
1. That this change, when it takes place in spring, is from 
light to a dark colour, and that in autumn tliis arrangement hi 
