467 
and Colour-change in Birds. 
in spring, we find the white feathers on the breast in all 
stages of colour between white and black. Messrs. Allen and 
Stone would have us believe that these are all new feathers, 
which have grown of that colour, and which will always 
remain of that colour. I have shot and examined many 
birds in the full summer dress, and it is very rare to find 
more than one or two feathers in this half-and-half stage on 
any single individual. What, then, has happened to the 
parti-coloured feathers so common on birds in spring ? 
Have they been again cast ? Moreover, it should be noticed 
that while feathers of various shades are found on the breast, 
the back is assuming, by direct moult, the full summer 
plumage, showing no tendency to any half-measures. But 
surely, if parti-coloured feathers are growing on the breast, 
and we suppose they are not going to be renewed, in such a 
case the bird would never acquire a purely black breast, and 
we should meet with the phenomenon of an individual with 
full breeding-dress on the back and only an apology for 
it on the breast. And if, on the other hand, the parti¬ 
coloured feathers are to be moulted again, we should find 
the bird having two moults in about six weeks, which is, to 
say the least, a very unlikely occurrence. That is about 
the limit of evidence that can be obtained from skins alone ; 
but I have kept several specimens of this species in captivity, 
in a large open aviary, and have watched the moult till 
it was completed, frequently catching up and examining 
the birds, and although I have never actually marked any 
individual feather, yet the observations seemed to me so 
conclusive, and at the same time so obvious, that I did 
not realize that there were still doubts on the subject. The 
moult is first noticeable by several feathers showing a slightly 
darker tinge; day by day more dark feathers show on the 
breast, and, as the moult becomes advanced, fewer parti¬ 
coloured ones*, till, finally, the bird has assumed its full 
summer plumage. 
That the white feathers actually do change may be further 
* See V. Fatio, Mem. Soc. de Phys. et d’Hist. Nat. de Geneve, xviii. 
(1866) p. 249. 
