ROCK GROUSE. 
329 
Gmelin; but it was reserved for Captain Sabine to 
point out clearly the differences between it and the 
Tetrao lagopus of the Highlands of Scotland; the 
principal of which are, the colours and markings of the 
summer plumage, and the size ; the rock grouse being 
smaller, having more of the brownish yellow in its 
summer dress, broader bars of black, and none of the 
cinereous tint which predominates in the ptarmigan.* 
If the latter visits the settlements on Hudson’s Bay- 
otherwise than accidentally, of which there is much 
doubt, Hearne and some other writers have confounded 
the two species under the name of rock grouse ; and, 
indeed, in their winter dress, the only perceptible 
difference between the two seems to be size ; hence we 
can learn nothing certain from these authors of the 
distribution of the species. Hutchins reports, that the 
rock grouse is numerous at the two extremities of 
Hudson’s Ba}r, but does not appear at the middle 
settlements, (York and Severn factories,) except in 
very severe seasons, when the willow grouse are 
scarce ; and Captain Sabine informs us that they abound 
on Melville Island, lat. 74° to 75°, in the summer. It 
arrived there in its snow-white winter dress on the 
12th of May, 1820; at the end of that month the 
females began to assume their coloured plumage, which 
was complete by the first week in June, the change at 
the latter period being only in its commencement with 
the males. Some of the males were killed as late as 
the middle of June in their unaltered winter plumage. 
In this respect the species differs from the willow 
* Captain Sabine observes, that i( the distribution of the coloured 
plumage of the rock grouse corresponds, both in the male and 
female, with the ptarmigan, the same parts of both species 
remaining white ; but there is much difference in the colour 
itself: the upper plumage of the ptarmigan is cinereous, with 
undulating and narrow black lines and minute spots ; whereas in 
the rock grouse each feather is black, cut by transverse broad lines 
or bars of a reddish yellow, which do not reach the shaft, and have 
spaces of black between them broader than themselves ; the feathers 
are tipped, in the male, with a light colour, that approaches to 
white in the female.” 
