BRITAIN'S BIRDS AND THEIR NESTS. Ill 



shape of some of the feathers — those of the tail — is 

 entirely different. The Blackcock's lyre-shaped tail, with 

 the white under-coverts showing in the notch, is well 

 known ; the Grayhen's tail is merely notched. The 

 cock's 'lyre' is not fully developed until his third year, 

 but he attains his black plumage in the first winter. 

 Earlier in the season the immature birds of both sexes 

 resemble the adult Grayhen. Barren — presumably old — 

 Grayhens attain a plumage similar to that of the adult 

 male, a phenomenon paralleled in some other species of 

 game-birds as well as among birds of prey, and probably 

 others. 



The Black-Grouse is to be found rather locally in 

 suitable parts of the south of England, the Midlands, 

 and Wales, although only as an introduced or re- 

 introduced species in some parts. Over most of Scotland, 

 including many of the Inner Hebrides, it is more regularly 

 and abundantly distributed. But it is one of the striking 

 differences between the fauna of Great Britain and that 

 of Ireland that this species is altogether absent from the 

 latter island. Attempts to introduce it, moreover, have 

 always ended in failure. Possibly the mild, damp climate 

 has a deteriorating influence on this hardy bird. Attempts 

 to introduce it in the Outer Hebrides and in Orkney 

 have also failed ; but suitable haunts are altogether 

 wanting in these places. For, unlike the two preceding 

 species, it is no bird of the open moorland, but a frequenter 

 of wooded countiy, such as abounds in the central 

 Highlands. It perches on trees freely, walking securely 

 enough on the branches ; but it nests and roosts on the 

 ground. 



In another more important respect the Blackcock also 

 differs from the Red-Grouse and Ptarmigan cocks, for 

 he is polygamous. Young Grayhens mate in their first 



