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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-Grouse, whose males first assume the summer 

 colours. The Eock-Grouse is found also on Melville Peninsula and the Barren Grounds, seldom 

 going further south in winter than latitude 63° in the interior, but descending along the coast 

 of Hudson's Bay to latitude 58°, and in severe seasons still further to the southward. It also 

 occurs on the Rocky Mountains as far south as latitude 55°. The Rock-Grouse in its manners 

 and mode of living resembles the Willow-Grouse, except that it does not retire so far into the 

 woody country in winter. Contrary, however, to what Hearne says, it is frequent in open woods 

 on the borders of the lakes in that season, particularly in the sixty-fifth parallel of latitude, 

 though perhaps the bulk of the species remain on the skirts of the Barren Grounds. It 

 hatches in June. The ground-colour of the egg is, according to Captain Sabine, a pale reddish 

 brown, and is irregularly blotched and spotted with darker brown." Audubon (B. of Am. v. 

 p. 122) writes respecting its occurrence in Labrador as follows : — " Whilst at Labrador I was 

 informed by Mr. Jones that a smaller species of Ptarmigan than that called the Willow-Grouse 

 (Lagopus saliceti) was abundant on all the hills around Bras d'Or during the winter, when he 

 and his son usually killed a great number, which they salted and otherwise preserved — and that 

 in the beginning of summer they removed from the coast into the interior of the country, where 

 they bred in open grounds, never, like the Willow- Grouse, retreating to the wooded parts. 

 They seldom appear at Bras d'Or until the last of the Wild Geese have passed over, or before the 

 cold has become intense, and the plains deeply covered with snow. While about his house they 

 repair to the most elevated hill-tops, from which the violence of the winds has removed the snow. 

 There they feed on the mosses and lichens attached to the rocks, as well as on the twigs and 

 grasses scantily found in such places at that season. They keep in great packs, and when dis- 

 turbed are apt to fly to a considerable distance, shifting from one hill to another, often half a 

 mile off." Mr. Dall met with it as far west as Alaska, and writes (B. of Alaska, Trans. Chic. Ac. 

 Sc. 1869, p. 289) that "it is not uncommon in the Gens du Large \}.Romanzoff~\ Mountains, 

 north-west of Fort Yukon, and has been obtained at Fort Yukon by Sibbeston, and in the 

 former locality by Mr. M c Dougal. It is not found further south or west to the best of my 

 knowledge." 



In its habits and mode of nidification the present species closely resembles its near ally the 

 common Ptarmigan. I have a large series of its eggs from Greenland obtained by Mr. Erichsen's 

 collectors, which are unclistinguishable from those of that species. 



The specimens figured are :- — on the one Plate a male and female in full breeding-plumage ; 

 on the second Plate another adult female with young in down, and a bird shot in early spring 

 just in the change, with the white plumage intermixed with brown feathers. On the same Plate 

 with Lagopus mutus in autumn plumage a specimen of the present species is also figured in the 

 same stage of plumage to illustrate the difference. 



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