Genus : Lyrurus 
Characters. — Feet feathered, and pectinated at the sides. Tail consists of eighteen 
feathers, the outer pairs being curved outwards at the extremity. Only two species 
are recognised in this genus — namely, the Common Black Grouse of northern Europe 
and Asia, and the Caucasian Black Grouse, Lyrurus mlokosiewiczi, whose habitat is 
confined to the Caucasian Range. 
THE BLACK GROUSE 
Lyrurus tetrix, Linnaeus 
Local Names. — Black Game, Blackcock (male), Greyhen (female); Heathcock, Heathpoult (Devon and 
Somerset) ; Grugiar Ddu (Black heather hen), Ceiliog Du (Blackcock), Ceiliog y Mynydd (Cock of 
the mountain), Ceiliog y Rhos (Heathcock) ( Welsh) ; Coilleach dubh (Blackcock), Lia-chearc, Cearc- 
lia (Greyhen), Cearc fhraoich (Hen of the heather) (Gaelic) ; Coq de bruyere (French) \ Birkhahn 
(male), Birkhuhn (female) (German). 
Adult Male. — Bill and feet, black; head, neck, nape, mantle, back, and rump, black, 
with steely-blue margins to the feathers ; tail, lyrate in shape, black in colour ; breast 
and belly, black, becoming ribbed with white about the vent ; under tail-coverts, white, 
and in the black form ribbed or pencilled with half-moon crescents of black ; 1 scapulars, 
lesser and median wing coverts, black, with a brown tinge ; bastard wing and secondaries, 
black, with broad bars of white ; primaries, brownish black ; the quills and outer edges 
being a pale brown. 
The Blackcock, like the male red grouse, has a very distinct eclipse plumage in 
late June, July, and August. At this season the bird has an untidy appearance, the 
whole of the plumage being duller and browner than at other seasons. The lower 
throat and cheeks are straw-colour, interspersed with black feathers, edged with a narrow 
margin of white. The crown of the head and whole of the back of the neck is a rich 
1 Adult males with black-ribbed under tail-coverts are not uncommon. In some instances, every feather is broadly 
edged with black. Mr. J. A. Harvie-Brown sends me the following note : " It seems that the young males in the first year 
have no such markings. The birds showing the most complete V-shaped black marks are birds in their prime, and after 
this they seem to gradually disappear, first from the returning inner edges of the feathers, and then by partial, and finally 
complete disappearance along the quills, until the under tail-covert feathers of very old birds are spotless. I have not, 
however, obtained a complete series." I cannot, however, quite agree with this. Certainly young birds are spotless, but 
I think that adults of the very dark form would retain the black markings until advanced age, though it is likely, as Mr. 
Harvie-Brown suggests, that in very old birds the markings would be lost. It seems impossible that Mr. Harvie-Brown could 
tell the age of the birds whose parts he examined. In a further note the writer says : " The very large series I had clearly 
demonstrated the steady flow and uninterrupted increase of the black pigment along the open ducts, quills, plumules, and filise 
until the prime of life. To all appearance all parts of the plumage were reached up to complete development (the only blanks 
being spring and summer stages). No breaks or spaces occurred whilst the dispersal of the pigment was progressive. Where 
blanks occurred in otherwise continuous markings I looked for other symptoms of decay or retrograding, and satisfied myself 
that retrograde action had begun." 
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