14 PACIFIC COAST AVIFAUNA No. 14 



they should be considered local areas within one life-zone simulatin.g those ol' 

 another, rather than areas really belonging to that other life-zone. 



The Canadian zone is found in all the higher mountains of the western part 

 of the state. It occurs from about 5,500 feet in the north and 6,000 in the soulh 

 to 7,500 or 8,000 feet. Its characteristic tree is the lodgepole pine {Pinus mur- 

 rayana). With this tree are found Douglas fir, Engelmann spruce, and alpine 

 fir {Abies lasiocarpa) . West of the divide several other species are found, such 

 as western white pine (Pinus monticola), western hemlock {Tsuga helerophylla), 

 arbor-vitae {Thuya plicata), and lowland fir {Abies grandis). Some of the 

 birds typical of this zone are the Franklin Grouse, the three-toed woodpeckers, 

 Hanunond Flycatcher, Rocky Mountain Jay, Lincoln Sparrow, Pileolated Warb- 

 ler, and Mountain Chickadee. There is much less difference in t)ie conditions 

 of this zone on the two sides of the divide than in the case of the Transition 

 zone. 



The Hudsonian zone occurs in all the higher mountains of the western half 

 of the state. It occupies comparatively small areas on the higher mountain 

 slopes, varying little in different parts of the state. It lies from 7,500 to 8,000 

 feet up to 9,000 or 9,500, but its upper limit varies greatly. The zone is easily 

 recognized by the stunted and often misshapen character of the ti'ces. It occurs 

 from the point where the trees begin to take on this character, ui> to timberline, 

 the limit of tree growth. The species of trees found in this zone un' Ml[)ine fir, 

 spruce, limber pine, and white-bark pine {Pinus albicaulis) . The last species 

 is the only one entirely characteristic of the zone. The one charactoristie bird is 

 the Rocky Mountain Pine Grosbeak. The Clark Nutcracker is usually more 

 abundant in this zone than elsewhere, and other species, found chiefly in the 

 Canadian zone, range up into this zone. Such species are the ^lontana and Pink- 

 sided juncos and Audubon Warbler. 



The Alpine-Arctic zone occupies the tops of the highest mountains above 

 timber line. In most parts of the state it covers only small scattered areas on 

 the peaks of the highest mountains or along very high ridges. Northwai'd it 

 covers a larger proportion of the mountain area. It can be best observed in the 

 Glacier National Park. The birds characteristic of this zone are the White-tailed 

 Ptarmigan, the Rosy Finches, and the Pipit. These birds have been found breed- 

 ing only in the northern part of the state, so that this zone in the south, so far as 

 it is known, has no characteristic breeding birds. It is probable that the Black 

 Rosy Finch, however, breeds in this zone in the southwestern ranges. 



The associational areas are those which have the same conditions of soil, 

 moisture or exposure, and hence a certain association of plants and animals 

 which depend either on those conditions directly, or on other forms of life in 

 the associations. Some associations are local in distribution, while others are 

 found over the greater part of the state. Some are limited to a single faiinal 

 area, while others are found in several such areas and often in more than one 

 life zone. A complete study of associational distribution in the state is not pos- 

 sible at present, but the following data on the more important and more widel.v 

 distributed associations should be of value. 



Associations are the most fundamental of distributional areas, for it is oT 



