No. 27. NORTH AMERICAN FAUNA. October, 1908. 



A BIOLOGICAL INVESTIGATION OF THE ATHABASKA- 

 MACKENZIE REGION. 



By Edward A. Pbeble. 



INTRODUCTION. 



The greater part of Boreal America falls naturally into three great 

 regions — the region tributary to Hudson Bay, that drained by the 

 Mackenzie and its tributary rivers, and that whose waters unite to 

 form the Yukon. The present report deals with the natural history, 

 especially the higher vertebrates, of the second of these great areas. 

 Though not offering to the student of geographic distribution so 

 many problems as the Alaska region, where the various combinations 

 of boreal, humid, and alpine conditions have resulted in the differ- 

 entiation of many well-marked races, the region drained by the Mac- 

 kenzie in many respects is the most interesting of these great natural 

 divisions. Many mammals, some of them among the most valuable 

 of the fur-bearing species, range over it, and also extend over large 

 portions of adjoining areas. Within its borders live the last wild 

 herds of that all but extinct species, the American bison, while an- 

 other equally notable ruminant, the musk-ox, abounds on its Barren 

 Grounds, where probably it is destined to make its last stand. 



In the spring, when its rivers and swamps are freed from the grasp 

 of the long Arctic winter, the region becomes the resort of millions of 

 birds which hasten to breed within its borders. These include repre- 

 sentatives, and in some cases the bulk of the individuals, of most of 

 the migratory game birds, which are of great economic importance 

 in the United States, where many of them winter. 



Though explored nearly a century later than Hudson Bay and 

 consequently not furnishing so many species new to science ( for 

 many animals first described from Hudson Bay are common to both 



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