on Melanism a?id Albinism in Birds. 243


patch. A pied Chaffinch, which I once caught in the garden,

became much whiter at the two succeeding moults ; and a pied

Blackbird sent to me a year or more ago showed an increase of

white after its autumn moult; both were delicate birds, and did

not live long, so that I conclude they were probably inbred.”


The pied Cordon-bleu above referred to died on Jan. 7th

1903 and I sent it to the Natural History Museum : oddly

enough an exactly similar example was sent to me a few days

later by one of the readers of “ The Feathered World.” My

specimen of this delicate little finch had been in my possession

about seven years.


In a letter to “ The Ibis ” in 1902, pp. 674-6, describing an

abnormal but very beautiful example of melauochroism in a

Gouldian Finch, I pointed out the fact that exceptionally vigorous

birds sometimes became quite black in old age, and I recorded the

case of a Song-Thrush which was seventeen years old when it

died, and had been in captivity sixteen years : this bird was

crippled with age and quite black. Similar instances occur in

the case of the Skylark. I ask the question in that letter,—“ Is

melanochroism in old age the result of unusual constitutional

vigour, as leucochroism seems to be of constitutional weak¬

ness?” This I am now convinced must be the case.


In his article “ On the Comparative Ages to which Birds

live ” (Ibis 1899, p. 25) Mr. J. H. Gurney observes—“ this

incipient albinism is not directly due to age, but to the artificial

conditions under which all birds are placed in captivity,” a con¬

clusion to which I think all owners of tolerably large aviaries

must demur, the conditions in many aviaries being only so far

artificial as they eliminate the causes which are liable to shorten

the lives of the more delicate birds.


In like manner, a well-known ornithologist spoke to me

recently of the extraordinary effect which captivity produces in

some of the Weavers when kept in aviaries, causing them to

become entirely black ; and he argued that, as these melanistic

forms were never shot in the wild state, they must have been

produced by unnatural food. %


If this were the true explanation of melanism in birds, it



