L 31-35 cm. Breeds on mountainsides and tundra,
barren and rocky terrain with only little vegetation. Sedentary, but in winter
sometimes in more sheltered habitats, e.g. in willow scrub and open birch
forests at upper tree-limit.
IDENTIFICATION: Slightly smaller than Willow Grouse but very similar
in shape, with rounded body and smallish head; toes feathered. In winter,
nearly all white with short, black tail. In summer, brown colours are more
grey-tinged than rufous, making it reasonably distinctive if seen well. - Adult
male spring (May-Jun [Jul]): Head, neck and upper breast and parts of flanks
and back dark grey-brown and black, finely vermiculated black and edged or
barred buff and white, giving a mainly dark grey general impression in the
field (Willow Grouse deep red-brown and hardly barred at all); lores
blackish; belly, wings and parts of flanks white. - Adult male summer (Jul-
Sep [Nov]): As in spring, but colour paler grey, less dark brown-grey; sparse
black patches on back typical; lores brown, speckled white. Paler than
Willow Grouse at same time of year, lacking rufous tinge. - Adult female
spring-summer: Differs from male in having more coarsely barred plumage
with more yellowish tinge, dark brown and black, barred and spotted
yellowish-buff and off-white. Lores rather pale. Compared with Willow
Grouse, throat and sides of head are a little darker and more greyish (not
tinged buff and ochrous, respectively). - Winter: Plumage all white, except
for black tail and black loral stripe on all males and, thinly, on some females;
most females have white lores (and may therefore be difficult to distinguish
from Willow Grouse). When seen close, note that the bill is smaller than on
Willow Grouse (and claws are on average darker). Generally forms large
flocks in winter, keeping on open mountainsides or in scrub and heather
rather than in forests (cf. Willow Grouse).
VOICE: Rather less vocal than Willow Grouse, but far from mute (in spite
of scientific name)! All calls rather similar, mostly low belching or dry,
snoring sounds. Actually only one call typical, an almost Garganey-like
creaking with characteristic rhythm, ‘arr orr ka-karrr’ (‘here comes the bride’;
sometimes only two or three syllables); appears to have song function (but at
times given by female, too), mostly delivered from ground in spring,
sometimes when flushed. A related shorter ‘urr-errr’ has been described as
‘perch-song’. In song-flight in early spring, male gives a belching sound
while descending on stiff wings, ending in a cackle, ‘ahrrrr-ka-ka-ka-ka-kaka’.
Alarm or aggression shown by a ‘kwa’ and variations. Call of female a
soft ‘kee-a’.L 31-35 cm. Breeds on mountainsides and tundra, barren and rocky terrain with only little vegetation. Sedentary, but in winter sometimes in more sheltered habitats, e.g. in willow scrub and open birch forests at upper tree-limit. IDENTIFICATION: Slightly smaller than Willow Grouse but very similar in shape, with rounded body and smallish head; toes feathered. In winter, nearly all white with short, black tail. In summer, brown colours are more grey-tinged than rufous, making it reasonably distinctive if seen well. - Adult male spring (May-Jun [Jul]): Head, neck and upper breast and parts of flanks and back dark grey-brown and black, finely vermiculated black and edged or barred buff and white, giving a mainly dark grey general impression in the field (Willow Grouse deep red-brown and hardly barred at all); lores blackish; belly, wings and parts of flanks white. - Adult male summer (Jul- Sep [Nov]): As in spring, but colour paler grey, less dark brown-grey; sparse black patches on back typical; lores brown, speckled white. Paler than Willow Grouse at same time of year, lacking rufous tinge. - Adult female spring-summer: Differs from male in having more coarsely barred plumage with more yellowish tinge, dark brown and black, barred and spotted yellowish-buff and off-white. Lores rather pale. Compared with Willow Grouse, throat and sides of head are a little darker and more greyish (not tinged buff and ochrous, respectively). - Winter: Plumage all white, except for black tail and black loral stripe on all males and, thinly, on some females; most females have white lores (and may therefore be difficult to distinguish from Willow Grouse). When seen close, note that the bill is smaller than on Willow Grouse (and claws are on average darker). Generally forms large flocks in winter, keeping on open mountainsides or in scrub and heather rather than in forests (cf. Willow Grouse).
VOICE: Rather less vocal than Willow Grouse, but far from mute (in spite of scientific name)! All calls rather similar, mostly low belching or dry, snoring sounds. Actually only one call typical, an almost Garganey-like creaking with characteristic rhythm, ‘arr orr ka-karrr’ (‘here comes the bride’; sometimes only two or three syllables); appears to have song function (but at times given by female, too), mostly delivered from ground in spring, sometimes when flushed. A related shorter ‘urr-errr’ has been described as ‘perch-song’. In song-flight in early spring, male gives a belching sound while descending on stiff wings, ending in a cackle, ‘ahrrrr-ka-ka-ka-ka-kaka’. Alarm or aggression shown by a ‘kwa’ and variations. Call of female a soft ‘kee-a’.
