1936] MAMMALS AND LIFE ZONES OF OREGON 21 



cipitation of 40 inches in the Willamette Valley to 80 inches near 

 the coast and along the upper slopes of the Cascade Range. The 

 greater part of this heavy precipitation occurs during the winter 

 months, when the mountains are being heavily laden with the deep 

 snows that lie late into the spring and in higher zones remain 

 throughout the summer. This abundant supply of water is shown 

 in the magnificent forest growth along the sides of the mountains 

 and toward the coast where the moisture is in still greater abundance. 

 The warmer and drier Willamette and other valleys are conspicu- 

 ously less-heavily forested and better adapted to general agriculture. 



MAMMALS 



Some of the characteristic mammals of the humid Transition Zone 

 of Oregon are Roosevelt's elk, Columbian black-tailed deer ? Oregon 

 white-tailed deer, Washington rabbit, Oregon brush rabbit, silver 

 gray squirrel, Douglas's squirrel, Townsend's chipmunk, Douglas's 

 ground squirrel, Oregon flying squirrel, dusky wood rat, ruddy deer 

 mouse, California red-backed mouse, tree mice (Phenacomys longi- 

 cawlus and silvwola), white-footed phenacomys, Townsend's and 

 gray-tailed meadow mice, Oregon creeping mouse, mountain beavers 

 (Aplodontia rufa and pacifica), jumping mouse Zapus princeps 

 trinotatus] , pocket gophers (Thomomys bulbivorus, oregonus, and 

 niger), and northwest coast bobcat (Lynx fasciatus). 



BIRDS 



Some of the breeding birds of humid Transition Zone are : Sooty 

 grouse, Oregon ruffed grouse, band-tailed pigeon, California pygmv 

 owl, Harris's woodpecker, northern pileated woodpecker, Lewis s 

 woodpecker, Vaux's swift, Steller's jay, Townsend's warbler, west- 

 ern winter wren, California creeper, Oregon chickadee, chestnut- 

 backed chickadee, wren tit, western golden-crowned kinglet, and 

 black-headed grosbeak. 



PLANTS 



The abundant vegetation of this division of the zone is to a great 

 extent peculiar to the Pacific slope and of species that range from 

 western British Columbia to northwestern California. The princi- 

 pal forest trees are sugar pine, Willamette pine, Jeffrey pine, nar- 

 row-cone pine, Douglas fir, western hemlock, lowland fir (Abies 

 (grandis), noble fir (Abies nobilis}, white fir (Abies concolor, includ- 

 ing lowiana) , incense cedar, western red cedar, Oregon yew, Oregon 

 maple, vine maple, Oregon alder, mountain alder, black cottonwood 

 (Populus trichocarpa) , tanbark oak, Oregon white oak, California 

 oak, western chinquapin, Oregon ash, madrone, California laurel, 

 cascara, western dogwood, Oregon crab apple, and black hawthorn. 

 The more characteristic shrubs are California hazel, wild cherry, 

 manzanita, Oeanothus thyrsiflorus and integerrimus, Garrya ellyp- 

 tica, mountain-laurel, salal, purple elderberry, devilsclub, red blue- 

 berry, evergreen blueberry, salmonberry, and thimbleberry. Some 

 of these humid Transition Zone species run more or less irregularly 

 along the middle-eastern slope of the Cascades where the low sum- 

 mit of the range allows considerable rain to pass over, but their 

 main abundance will be found on the west slope. 



