THE WILLOW GROUSE AND PTARMIGAN. 37 



Range. — Circum-polar, inhabiting the Arctic tundras of 

 Europe, Asia, and America. 



Adult Male and Female.— Winter Plumage. — Pure white, with the 

 exception of the black outer tail-feathers, which remain un- 

 changed. 



Adult Male.— Summer Plumage. — The head and neck chestnut, 

 shading into dark chestnut, or sometimes even black on the 

 chest ; rest of the upper-parts chestnut, mottled and barred 

 with black, and often tipped with buff; flight-feathers and rest 

 of under-parts white, as in winter. This is the most com- 

 plete form of summer plumage found in birds inhabiting 

 the more temperate parts of the range ; in those from high 

 altitudes, all the upper-parts, from the back of the neck, remain 

 white, merely interspersed here and there with a few feathers 

 of the summer plumage. 



Adult Female.— Summer Plumage. — Very similar to the female of 

 the Red Grouse in breeding plumage, but the buff markings are 

 paler and more conspicuous and the flight-feathers are white. 

 Unlike the male, the summer moult of the female, no matter 

 the locality, is always complete, birds from the far north of 

 Alaska being in quite as complete breeding-dress as those from 

 more southern latitudes. 



Adult Male and Female.— Autumn Plumage. — Head, throat, and 

 chest light brick or pale chestnut colour, usually with finely 

 m:ttled black cross-bars (in the female these parts are generally 

 largely intermixed with the old summer feathers) ; the upper- 

 parts are black, with narrow bars of rufous or rufous-buff. The 

 flight-feathers, tail-feathers, and feathers of the feet are, as in 

 other members of this genus, renewed at this season. 



Quite young Ijirds have the first flight-feathers greyish-brown, 

 mottled with bufT at the tip and along the outer web. 



Habits.— These birds in every way resemble the Red Grouse. 

 Their call is the same, and their eggs are indistinguishable, but 

 they inhabit somewhat different ground, being chiefly found 



