THE CAPERCAILZIES. 49 



black, but the black bars and markings on the breast are much 

 finer than in the female of Z. tetrix, and the tail is longer. 

 Total length, i6'6 inches; wing, 77; tail, 5*5; tarsus, 1*85. 



Range. — This species is only found in the Caucasian Moun- 

 tains 1 , 



Changes of Plumage — The young males are peculiar in retain- 

 ing a hen-like plumage throughout the first year, and probably 

 till the second moult, thus differing entirely from the young 

 males of Z. tetrix, which attain their black plumage at the 

 first autumn moult, and by December closely resemble their 

 male parent. 



THE CAPERCAILZIES. GENUS TETRAO. 

 Tetrao, Linn. S. N. i. p. 273 (1766). 

 Type, T. urogallus, Linn. 

 The members of this genus are all birds of large size, and, 

 like the Black Grouse, have the tail composed of eighteen 

 feathers, but are distinguished by having the middle pair of 

 feathers much longer than the outer pair, which produces a 

 rounded or wedge-shaped appearance when the tail is spread. 

 There are no elongate tufts of feathers on each side of the 

 neck, nor inflatable air-sacs in the male, and the outer flight- 

 feathers are not attenuated or sickle-shaped. 



I. THE CAPERCAILZIE. TETRAO UROGALLUS. 



Tetrao urogallus, Linn. S. N. i. p. 273 (1766); Meyer, Unser 



Auer.-, Rackel- und Birkwild, &c. pp. 1-15, pis. 1-3 (1887); 



Millais, Game-Birds, pp. 1-20, pis. and woodcuts (1892) ; 



Ogilvie-Grant, Cat B. Brit. Mus. xxii. p. 60 (1893). 

 Adult Male. — Above dark grey, shading into reddish-brown 

 on the wings and finely mottled with black ; a metallic green 

 band across the chest, and the throat glossed with the same 

 colour. Middle of the back not barred with black j the 

 shoulder-feathers not tipped with white ; and the breast and 

 belly black, a few feathers in the middle being tipped with 



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