24 



PACIFIC COAST AVIFAUNA 



No. 14 



Warbler, and the Rocky Mountain Nuthatch. This is the only easily reco.unized 

 tree association of the Iludsonian zone. 



The Douglas fir association is one of tlie most inii)oi'tant of tiie coniferous 

 tree associations from the standpoint of bird life. It occurs in the Transition and 

 Canadian zones. The firs form a rather open forest, mainly on north slopes in 

 the lower foothills of the Transition, and on steep south slopes of rocky soil in 

 the Canadian. A number of birds show a decided preference for tiiis association 

 over others, and most of the species breeding in the lodgepole pine are found in 

 greater numbers in the firs. The characteristic species are the Olive-sided Fly- 





Fig. 8. A SPRUCE FOREST IN GERMAN GULCH, SIL- 

 VER Bow County; May, 1910. Brekdixg 

 GROUND of Rocky Mountain Creeper, Goi.- 



UEN-CROWNEI) KlN(iLET AND WINTER WREN. 



Canadian zone. 



catcher, Western Tanager and Ruby-crowned Kinglet. Others I'ound in it are 

 the Ruffed Grouse, Sparrow Hawk, Pygmy Owl, Hairy Woo(lp«>cl>:er, the three- 

 toed woodpeckers, Ked-shafted Flicker, Hammond Flyeatcher, Black-headed Jay, 

 Clark Nutcracker, Chipping Sparrow. Ihc juncos, Audul)ou Warbh'i-. Mountain 

 Chickadee, Olive-backed Thrush, and Robin. West of the continental divide, in 

 tile northwestern mountain region, a variation of this association is found in a 

 mixture of fir and tamarack. The same species of birds are foiim! in it, excejit 

 that two northwest species, Cassin Virco and Towuseud Warl)ler, arc added. .\t 

 low elevations firs occur scattered througli tlic foothills, bordering on either the 



