INTRODUCTION 
XXXV 
The Canadian Zone comprises “ the southern or lower part of the 
great transcontinental coniferous forest.” It is the zone of firs, 
spruces, and white pines, which on Mt. Shasta are represented by 
the Shasta fir and the silver pine. One of its characteristic animals 
is the mountain beaver, and it has also the porcifpine, pine squirrel, 
bear, wild cat, wolf, and other mammals. It is the home of the 
crossbill, Lincoln sparrow, and Arctic three-toed woodpecker, and 
frequented by birds found in the Hudsonian zone, such as the sooty 
grouse, rufous hummingbird, siskin, j uncos, warblers, kinglets, and 
solitaire, together with a number found also in the next lower zone 
(the Transition), such as the white-headed, hairy, and pileated 
woodpeckers, nighthawk, olive-sided, Hammond, Wright, and west¬ 
ern flycatchers, Steller jay, Louisiana tanager, Macgillivray war¬ 
bler, and robin. 
The Transition Zone, in which northern and southern elements of 
flora and fauna often overlap,, is characterized in the west by the 
yellow pine ( Pinus ponderosa), several species of oaks and manza- 
nita, together with buck brush and sage brush. Some of the char¬ 
acteristic mammals are the big gray pine squirrel, the gray fox, 
and various species of chipmunks, spermophiles, and pocket go¬ 
phers. Among birds there are the western wood pewee, Gairdner 
woodpecker, Lewis woodpecker, California pygmy owl, green-tailed 
towhee, pygmy nuthatch, red-breasted sapsucker, and Brewer spar¬ 
row, mixed with many species from the Upper Sonoran, the zone 
below, such as the California jay, valley quail, California wood' 
pecker, and spurred towhee. 
The Upper Sonoran Zone of the west is characterized by junipers, 
piiion, and various oaks, jack rabbits, cottontails, five-toed kangaroo 
rats, and several species of wood rats, the canyon wren, western lark 
sparrow, California chewink, and California bush-tit, while many 
Transition zone species also occur. 
The Lower Sonoran Zone, coming next above the Tropical zone, 
is the zone of the hot valleys, where live-oaks, mesquites, and creo¬ 
sote bushes abound, and the characteristic mammals and birds are 
the four-toed kangaroo rat, cotton rat, and spotted skunk, the 
mockingbird, nonpareil, verdin, pyrrhuloxia, road-runner, caracara, 
white-necked raven, phainopepla, and scaled quail. 
of Mt. Shasta; ” North American Fauna, No. 3, “ Results of a Biological Sarvey of San 
Francisco Mountain Region and Desert of the Little Colorado; ” “ The Geographic Dis¬ 
tribution of Life in North America, with Special Reference to the Mammalia,” Proc. 
Biol. Soc. Wash. vii. April, 1892, 1-64. 
