some spontaneous Variations in Mallard & Muscovy Ducks. 87


wild bird descended from the other (white-headed) tame duck showed

red round the eye, this has not yet appeared in the purely tame

daughter of the black tame bird, which daughter yet has obviously

the clumsy tame shape. Probably her premature breeding has

arrested development.


I may here mention another curious instance of variation in

Muscovy ducks which occurred at the London Zoo several years ago.

In this case, a tame drake, normal except for a few white feathers

and a general deficiency of green sheen, accompanied by a slaty

tinge, was mated to two tame ducks of the white-headed variety.

The offspring were about half normal in the down, the other half being

pale drab or lavender-grey above instead of black. The normal

birds grew up normal, but got white heads later, as far as I saw in

those which were kept ; of the grey-hacked six were kept (the others

being sold in the down), and these all grew up pale grey like Anda¬

lusian fowls ; two had the erectile crown-feathers white. Both these

were drakes ; in fact only one of the six was a duck.


I have seen this grey variety elsewhere, but it is rare; but of

the few I have thus seen three were females, though those were not

all grey, but about half white. It evidently occurs sporadically,

and may not be sex-limited to any great extent.


Some interesting conclusions may be drawn from the study

of these familiar ducks for they throw light on several colour

problems. We see that a new variation in down-colour (black) may

arise suddenly, and be correlated with an adult plumage differing

little (in the Mallard) or not at all (in the Muscovy) from the

normal type. Furthermore, in the Muscovy case the black type

of young seem to have decidedly dominant tendencies.


This may help to explain the curious fact that of our two

most familiar British diving-ducks, the Pochard (Nyrocct ferina ) and

the Tufted Duck (.Fuligula fuligula), the former has pied young

much like the young of the Mallard, and the latter has ducklings all

black except for the yellowish abdomen. Those theorists who would

maintain that all differences of colour have a close relation to

the environment would be puzzled to say why the young of these

birds, breeding on the same fresh waters and remarkably equal in

diving power, should be so different in colour; one type must in-



