COMMON PTARMIGAN. | 427 
or here and there in the immediate vicinity of where he is standing. 
Ptarmigan appear to be subject to the same disease as Red. Grouse ; 
but it is not nearly so widely spread nor so disastrous in its results, pro- 
bably because the Ptarmigan is not so highly protected or its natural 
enemies destroyed to such a great extent. 
The Ptarmigan in winter plumage is pure white, with the exception of the 
tail-feathers, which are black with narrow white tips. The male has also 
the lores and a stripe behind the eye black. Bill and claws blackish brown ; 
irides hazel; above the eye there is a dull scarlet wattle, which increases 
in size and brilliancy curing spring. The white plumage of the wings, 
outer wing-coverts, lower breast, belly, and the under tail-coverts is for 
the most part retained until it is renewed in autumn, though many of the 
white feathers of the underparts are often replaced in summer by coloured 
feathers. The rest of the plumage appears to be gradually moulted twice 
before the final autumn moult, the spring feathers being generally nearly 
black, with buffish-brown vermiculations, and those of autumn pale grey 
with black vermiculations. The change of feathers proceeds so slowly 
that the summer moult begins before the spring moult is complete, so that 
it is impossible to obtain a bird in full spring or summer plumage. The 
female retains the white on the quills and outermost wing-coverts only, 
the ground-colour of all the rest of the feathers, except that of the tail, 
being buff, transversely barred with semi-confluent black bands, and tipped 
with nearly white, a plumage which appears to be retained until the 
autumn moult. In birds of the year, after their first spring moult *, the 
small feathers are very much vermiculated with buffish brown ; but the 
black becomes more and more predominant every year, until in very old 
birds the buffish brown almost disappears from the back and breast. In 
winter the toes are protected with thick feathers reaching halfway down 
the claws; but in summer the fore half of the toes is almost bare. Young 
in down are very similar to those of the Red Grouse. 
* Tt is not certain that the spring plumage is obtained by a moult. It is possible that 
the white feathers gradually change colour in spring, only those being moulted which, by 
accident during winter, have been so injured that they have lost the power of changing 
colour. Willow-Grouse kept in confinement are said to change from the white winter 
dress into the brown summer dress without moulting more than ten per cent. of their 
feathers ; and early spring examples of this species show white feathers with brown bases, 
and brown feathers with white tips, apparently proving that the change of colour begins 
at the base of the feather. 
