THE WILLOW GROUSE AND PTARMIGAN. 3 1 



with narrow irregular bars and mottlings of rufous, and a bun 

 spot at the tip of most of the feathers (PI. III., Figs. 2 and 3) ; 

 chest and flank-feathers narrowly and often irregularly barred 

 with rufous and black, and usually more or less tipped with 

 buff (PI. III., Figs. 10 and 11). The rest of the under-parts 

 are dark chestnut, mottled and barred with black, or black, 

 barred with chestnut. The typical white-spotted form differs, 

 of course, in having the feathers of the under-parts widely 

 tipped with white. 



Adult Female.— Summer Plumage. 



A. Feathers of the Upper-parts. 



So far as I have been able to ascertain from examining a 

 large number of specimens, the summer feathers of the upper- 

 parts are always attained by moult, and never by change of 

 pattern. The summer moult of these parts is very complete, 

 and the transformation from the autumn-winter plumage very 

 remarkable. Every female assumes the summer plumage, and 

 at this season all the different types closely resemble one an- 

 other, but one can generally tell by the colour of the under-parts 

 to which form an individual belongs. In the average female in 

 full breeding dress the upper-parts may be described as black, 

 each feather being rather widely margined, barred, and marked 

 with orange-buff (PI. III., Fig. 1). The protection afforded by 

 this plumage is so perfect that, when the bird is sitting on its 

 nest among heather and dead grass, it may easily remain unob- 

 served, though only a few yards distant. 



This plumage, however, varies much in different individuals, 

 birds from the west of Scotland, Yorkshire, and Ireland having 

 the orange-brown bars much brighter and wider than in the 

 more finely mottled and darker specimens generally charac- 

 teristic of the east of Scotland. 



B. Feathers of the Sides and Flanks. 

 By the first week in May the summer plumage of the female 



