WILLOW GROUSE. 219 



with rusty yellow. Tail with black and rusty yellow 

 wavy transverse streaks. 



By degrees the young become like the mother, as 

 the brown wing feathers in August are changed for 

 white, and the black tail feathers shoot out. The 

 white wing feathers grow in this manner: — The outer 

 ones of the first and second order come at one time; 

 the third and fourth brown wing feathers are shed 

 last in the young birds, generally after the middle of 

 August. In this or the foregoing month the old birds 

 shed their tail and wing feathers, and in the same or 

 beginning of the next month the horny covering on 

 the claws. 



Male and female in winter dress. Beak black; eye 

 spot smaller and paler; the fourteen tail feathers black, 

 with white edges on the ends, very broad on the 

 middle ones. The shafts of the five or six first wing 

 feathers brown. For the rest, the whole of the 

 plumage is snow white; tarsi and toes thickly covered 

 with bushy feathers, like hair, which, similar to the 

 foot of a hare, lie even on the sole of the foot. 



The transition from summer to winter dress takes 

 place at different times in different places and seasons, 

 but generally in September and October. In the 

 middle of the last-named month we see some white 

 Bipa, and some speckled, on account of some of the 

 summer feathers remaining. In the end of April or 

 May the spring moult takes place, and even in the 

 beginning of June we find occasionally winter feathers 

 remaining. During the period of transition we see 

 speckled birds with more or less white feathers among 

 the speckled ones. 



The spring moult comes on in this way: — The 

 coloured feathers first appear on the head and neck, 



