voracity of Arctic
and red foxes, wolves and gluttons, rough-legged buzzards and ravens,
owls and skuas which have followed them; the survivors pay no heed.
Where these go, how they end, none can say; but certain it is, that the
tundra behind them is as if dead, that a number of years pass ere the
few who have remained behind and have managed to survive slowly multiply
and visibly re-people their native fields." This eloquent passage
reminds us of the manner in which migrations of all kinds of animals
have taken place in former times, and are still taking place. It is
principally want of food which compels them to search for new homes.

On page 91 I have referred to some birds which have come to us from the
north. One of these, the Snow Bunting (_Plectrophenax nivalis_), is a
typically Arctic species. In summer it is widely distributed, and is
found in Spitsbergen, Novaya Zemlya, Siberia, and the Arctic Regions
generally. In winter it migrates down into North America, into Japan,
Northern China, Turkestan, Southern Russia, and occasionally even across
Europe into North Africa. Very characteristic Arctic birds are the Eider
Ducks belonging to the genus _Somateria_. Three species have visited
the British Islands. The common Eider Duck (_S. mollissima_), which is
of such high commercial value, is abundant in Norway and northward,
throughout the Polar Regions. The appearance of the King Eider (_S.
spectabilis_) on our coasts is an extremely rare occurrence, and even in
Norway it is only known as a visitor, but on Novaya Zemlya and along the
Arctic shores of Siberia, in Greenland and Arctic North America, it is
known to breed. The third species, Steller's Eider (_S. Stelleri_),
seems to be still rarer, and only in the Aleutian islands and in the
north of Alaska can it be said to be at all abundant. It is probable
that the famous Great Auk (_Alca impennis_, Fig. 9) also was a typical
Arctic species. Its range extended to both sides of the Atlantic. In
Newfoundland and on the coast of Iceland it is known to have been met
with in considerable numbers within historic times; and no doubt, like
all Arctic species, it extended farther southwards at a more remote
period.

[Illustration: Fig. 9.--The Great Auk (_Alca impennis_).]

The members of the genus _Lagopus_, including the various species of
Grouse, are likewise of northern origin. The British Red Grouse (_L.
scoticus_), which may be looked upon as a form of the Scandinavian