NATURAL AREAS AND REGIONS 



135 



All of the main head tributaries of this 

 great stream, the Stewart, Pelly, Lewes, 

 and White, together with the Porcupine, 

 rise either within Yukon's borders, or 

 close to them, and drain about four- 

 fifths of its territory. Most of the area 

 remaining contributes to the Liard and 

 Peel. 



As might be inferred from the fore- 

 going discussion of its drainage, the 

 Yukon River affords the principal 

 means of access to most parts of Yukon 

 Territory. From Skagway, at the head 

 of navigation on Lynn Canal, the White 

 Pass and Yukon Railway takes one to 

 Whitehorse at the head of steamboat 

 navigation on the Yukon, which may, of 

 course, be easily descended with or 

 without power. From their junctions 

 with the Yukon, the Pelly, Stewart, 

 and many smaller streams may be 

 ascended by small power boats or by 

 tracking well toward the main divide, 

 affording access to alpine areas of large 

 extent. The Frances Lake region, which 

 is drained by Frances River and other- 

 tributaries of the Liard, may be reached 

 by canoe from the upper Pelly, or from 

 the Dease Lake region of British 

 Columbia. 



Faunally and florally, Yukon has close 

 affinities with both Mackenzie and 

 Alaska. Comparison of lists of plants 

 of the three sections show very few 

 differences. Their mammal and bird 

 faunas are also strikingly alike. 



Of the large game animals of Yukon 

 the mountain sheep, found on both the 

 eastern (Mackenzie) and the western 

 slopes of the main Rocky Mountain 

 range, here generally referred to as the 

 Mackenzie Mountains, as well as in many 

 of the ranges to the westward, from 

 southern Yukon north to the Arctic 

 watershed, is probably the most interest- 

 ing. This animal (Ovis dalli), is found 

 in its typical form in many of the ranges 

 of northern Yukon. To the south it 

 gradually becomes darker, finally merg- 

 ing into the dark race named Ovis stonei 

 of northern British Columbia. Moose, 

 caribou, black and grizzly bears, and 

 (in extreme southeastern Yukon) moun- 



tain goats, are also found in some 

 numbers. 



Most of the small mammals show 

 affinities with both Mackenzie and 

 British Columbia, in varying degrees. 

 The chestnut-cheeked meadow mouse 

 (Microtus xanthognathus) , the Hudson 

 Bay jumping mouse (Zapus hudsonius), 

 the Rocky Mountain shrew (Sorex 

 obscurus), and the Yukon chipmunk 

 (Eutamias b. caniceps) are found in both 

 the Mackenzie and Yukon regions. 

 The British Columbia wood rat (Neo- 

 toma c. saxamans) is a Rocky Mountain 

 type, extending northward from British 

 Columbia into southern Yukon. 



The avifauna of Yukon, especially as 

 regards the smaller land birds, shows 

 close affinities with the Mackenzie 

 Valley. Conspicuous are the following 

 species, most of which probably have a 

 breeding range which is continuous from 

 Mackenzie to Yukon by way of the low 

 valleys tributary to the upper Liard 

 and thus including northeastern British 

 Columbia. A partial list follows: Co- 

 laptes a. borealis, Chordeiles virginianus, 

 Empidonax trailli alnorum, Euphagus 

 carolinus, Passerculus sandwichensis al- 

 audinus, Zonotrichia leucophrys gambeli, 

 Junco hyemalis, Petrochelidon lunifrons, 

 Hirundo erythrog aster, Tachycineta bi- 

 color, Vermivora celata orestera, V. 

 peregrina, Dendroica aestiva rubiginosa, 

 D. coronata, D. striata, Seiurus auroca- 

 pillus, S. noveboracensis notabilis, Wil- 

 sonia pusilla, Sitta canadensis, Pen- 

 thestes atricapillus septentrionalis, Hylo- 

 cichla aliciae, H. ustulata swainsoni, H. 

 a. pallasi, and Ixoreus n. meruloides. 

 Species which extend northward from 

 western British Columbia include the 

 following: Selasphorus rufus, Pica p. 

 hudsonica, Dendroica townsendi, Empi- 

 donax hammondi, Zonotrichia coronata, 

 and Tachycineta thalassina lepida. 

 Most of these reach the upper Yukon 

 (Canadian Zone) only. 



2. The Barren Grounds (Arctic Zone) 



Under this heading will be considered 

 the great area lying to the north and 

 northeast of Great Bear and Great 



