1905.] HYBRIDS AMONG NORWEGIAN BIRDS. 17 



Female, winter plumage. Principal colours brownish black, reddish 

 brown, and white. 



The upper sur face, br east and sides have reddish brown and black 

 cross bars, each feather with a white, or greyish white margin. The 

 abdomen is principally white. 



The sides of the head without any distinct stripes, mottled with 

 brown, black and white; tail-feathers black, their outer web mottled 

 with brown and white- The upper tail-coverts are of the colour of the 

 back, the under coverts white 1 . 



Old female, summer and autumn plumage. Differs from the winter 

 plumage in having broader reddish yellow cross bars, and in the barred 

 tail and under tail-coverts. 



The black and reddish yellow cross bars on the sides of the body 

 in particular are fewer in number and broader, like those in the sum- 

 mer plumage of L- lagopus, fetn. The head and neck are uniformly 

 variegated with cross bars of reddish yellow and black, sometimes with 

 a white margin. The tail-feathers are black, barred with reddish 

 brown and edged with white; the tinder tail-coverts with cross bars of 

 reddish yellow and black, and broad white tips. The toes thickly fea- 

 thered. {One specimen in the Christiania Museum, caught in Inder øen 

 in Odober, 1892). 



Young male, (of the size of a female L. lagopus). Still almost 

 entirely clothed in the narrow, loose feathers of the young Mrd, thickly 

 barred with rusty brown and black. 



TJie upper surface and the tail almost as in the young of L. la- 

 gopus, each feather being brownish black, with narrow, rust-coloured 

 bars or wavy lines. The under surface with black <ind rusty brown 

 cross bars of regular width, very much as in the young of L. tet r i x. The 

 under tail-coverts whitish grey with brownish black transverse lines. 

 The toes still almost naked, and only thinly feathered on the innermost 

 toe-joint: the comb-like scales on the last joint are only indicated 2 . (One 

 specimen in the Christiania Museum, caught in Odalen in September, 

 1880). 



Young male, autumn plumage, fully grown. Winter plumage acquired 

 except as regards the head and neck, which are those of the chick, 

 as also a few breast and side feathers These parts are therefore the last 

 to change. The featheving of the toes still scanty. (There are several 

 specimens in the Christiania Museum, caught in Odober and November.) 



1 The winter plumage of old females may sometimes almost exactly re- 

 semble that of the male in colour (little reddish brown), the dark 

 feathers on the breast being almost entirely without the light cross 

 bars, and the black and white stripes on the sides of the head being 

 distinct. (One specimen in the Christiania Museum, caught in Rånen in 

 November, 1894). 



2 At the same time, in the outermost tail-feathers, the wing-feathers, 

 and the middle of the abdomen (which was white), this specimen had 

 assumed its winter garb, thus showing that these parts are the first 

 to change in the chick. 



Vid.-Selsk. Forh. 1905. No. 11. 2 



