THE TUNDRA AND ITS FAUNA 27 
it appears to winter in the Arctic, notably in Green- 
land. 
Wherever in the tundra region lemmings and small 
birds are to be found, there occurs the snowy owl 
(Nyctea nivea), though it does not seem to be common 
except where lemmings are abundant, as in Nova 
Zembla and parts of the mainland of Northern Asia. 
The bird has a general resemblance in coloration to 
a ptarmigan in winter plumage, and often lives in the 
stony regions frequented by that bird, upon which the 
owl preys. It is, however, no exception to the rule that 
the carnivorous animals of these barren regions need to 
lay the sea under contribution as well as the land, for it 
eats fish in addition to birds and small mammals. It 
winters in the tundra, and is a very characteristic bird 
of the region. Another predatory bird of the Arctic is 
the Greenland gerfalcon (Falco candicans), a beautiful 
bird, predominantly white in colour, which inhabits 
Greenland and Arctic America, and is represented by 
an at least closely allied species in Northern Asia. It 
preys upon ptarmigan and other birds, and also upon 
lemmings, and winters in Greenland. The third pre- 
daceous bird of the tundra is the raven (Corvus coraz), 
which is the scavenger of the region, and will eat 
practically anything from land or sea. 
As is to be expected from the unfavourable con- 
ditions of life, reptiles and amphibians are absent, and 
fresh-water fish are not abundant. Representatives of 
the salmon family occur in some lakes, but there is 
nothing characteristic. 
Among the invertebrates the insects present some 
interesting points. Except in Spitsbergen and Nova 
Zembla, mosquitoes are enormously numerous, and 
form in many regions a terrible plague. It may seem 
