Internal taxonomy confused, many subspecies often lumped, although in quite different ways: nominate sometimes considered to include koreni, birulai, kamtschatkensis, alascensis, albus, ungavus and others, from Scandinavia to Quebec; subspecies of south-eastern Siberia also often merged, sserebrowsky in okadai and kozlowae in brevirostris. Irish birds occasionally awarded separate subspecies, hibernicus.
The following 22 subspecies are recognised:
scotica (Latham, 1787) - British Isles.
variegata Salomonsen, 1936 - Islands off Trondheim, Norway.
lagopus (Linnaeus, 1758) - Scandinavia, Finland, northern European Russia.
rossica Serebrovsky, 1926 - Baltic countries and central Russia east to Kama Basin.
birulai Serebrovsky, 1926 - New Siberia Is.
koreni Thayer & Bangs, 1914 - Siberia from Urals and Yamal Peninsula to Pacific, south to Tomsk, Krasnoyarsk, Yakutsk and northern coast of Sea of Okhotsk.
maior Lorenz, T, 1904 - South-eastern Russia, northern Kazakhstan and south-western Siberia, east to Altai foothills.
brevirostris Hesse, 1912 - Altai and Sayan Mts.
kozlowae Portenko, 1931 - Western Mongolia, in Tannu Ola, Khangai and Kentei Mts.
sserebrowsky Domaniewski, 1933 - Eastern Siberia, from L Baikal to Sea of Okhotsk, south to Khingan Mts and Sikhote Alin Mts.
kamtschatkensis Momiyama, 1928 - Kamchatka and northern Kuril Is.
okadai Momiyama, 1928 - Sakhalin I.
muriei Gabrielson and Lincoln, 1959 - Eastern Aleutian Is and Kodiak I.
alexandrae Grinnell, 1909 - Coastal islands of south-eastern Alaska and north-western British Columbia.
alascensis Swarth, 1926 - Alaska.
leucoptera Taverner, 1932 - Arctic islands of northern Canada (Banks, Victoria, Southampton, Baffin) and adjacent mainland.
alba (Gmelin, JF, 1789) - Northern Canada, from northern Yukon and central British Columbia to Gulf of St Lawrence.
ungavus Riley, 1911 - Northern Quebec and northern Labrador.
alleni Stejneger, 1884 - Newfoundland.
pallasi Portenko, 1972 - British Isles.
dybowskii Stegmann, 1934 - Coastal Norway (islands off Trondheim Fjord).
hibernica (Kleinschmidt, 1919) - Baltic countries to central Russia.
The Reader's Digest Book of British Birds 1980, 3rd Edition, Drive Publications Ltd ISBN 0 340 25308 8
Birds in Colour Campbell, B., 1960, Penguin Books Ltd
The Pocket Guide to Nest and Eggs Fitter, R.S.R., 1954, Collins
RSPB Handbook of British Birds Holden, P., Cleeves, T., 2002, A & C Black ISBN 0 7136 5713 8
Birds of Britain and Europe Sterry, P., et al., 2001, AA Publishing ISBN 0 7495 3068 5
The Popular Handbook of British Birds Hollom, P.A.D., 1973, H.F. & G. Witherby Ltd ISBN 0 85493 002 7
BirdLife International Species Factsheet