314 ANDERSON: EXPLORATIONS IN THE ARCTIC 



ological work. The reports of this expedition are now being 

 published by the Canadian government in extended form, the 

 separates on each group being distributed as soon as printed. 



The principal difficulties in Arctic zoological work are (i) 

 difficulty of transportation; (2) Hmited fauna in winter; (3) 

 limited scope for field work in each summer; (4) necessity of 

 moving at best season for field work. 



It is worthy of note that the eastern North American land 

 fauna runs far to the westward along the Mackenzie River sys- 

 tem. Traces of Western influences begin to appear in the 

 Mackenzie delta. 



Tongues of the Hudsonian life zone extend far beyond the 

 Arctic Circle in places. The isothermal lines are very irregular. 



The prevailing east and west migration along the Arctic coast 

 brings some Pacific forms far east along the coast. 



There is an extensive north and south bird migration along 

 part of the Mackenzie system, the Anderson River, Liverpool 

 Bay, and towards Banks Island. 



There is little migration along the Coppermine River. 



Traces of the Siberian fauna come across from Bering Strait 

 and Kotzebue Sound to the Colville delta on the Alaskan Arctic 

 coast. 



There has evidently been a great diminution of some forms of 

 bird life in the Arctic in recent years, the same as elsewhere, 

 but this is not primarily due to destruction by natives, except 

 perhaps in parts of western Alaska. 



The reduction of game and fur animals is due principally to 

 white men's influence, directly or indirectly. The numbers of 

 individuals and conditions of existence of many species are 

 rapidly changing over many large areas in the Arctic, and causing 

 rapid and extensive shifting of native population. 



The Arctic marine life is fairly uniform in circumpolar regions, 

 the conditions of life being nearly uniform. Large series of 

 terrestrial animals show that there is less variation of some 

 species over large areas, than has been supposed. 



