288 CALIFORNIA MAMMALS. 



Zone in California. A few species of plants constitute the only 

 peculiarly Arctic life in California, as the areas are so small that 

 animal life of strictly Arctic species has disappeared, with the 

 possible exception of insects. 



The Boreal Zone is forested nearly throughout its extent in 

 California. The principal forest trees are the Foxtail Pine, 

 White-barked Pine, Mountain Pine, Tamarack Pine, and Red 

 Fir. The Californian mammals peculiar to this zone are the 

 Gray-headed Pika, Mountain Beaver, Yellow-bellied Marmot, 

 Belding- Ground Squirrel, Alpine, Sierra Nevada and Alpine 

 Chipmunks, Californian Pine Squirrel, Black Fox, Wolverine, 

 Pine Marten and Ermine. Some of the birds breeding princi- 

 pally or exclusively in this zone are Sooty Grouse, White-headed 

 Woodpecker, Williamson Woodpecker, Western Niglithawk, Cal- 

 liope Hummingbird, Olive-sided Flycatcher Gray-eared Finch, 

 White-cro'wned Sparrow, Lincoln Sparrow, Thick-billed Spar- 

 row, Green-tailed Towhee, Audubon Warbler and Black- 

 throated Gray Warbler. The Californian part of the Boreal Zone 

 may be called the Californian Alpine Fauna. 



The Transition Zone is of considerable extent in northern 

 California, but is of less extent in the southern part of the State, 

 where it is limited to the sides and upper parts of the moun- 

 tains, except that small part rising above about 7,000 feet alti- 

 tude, which is Boreal. In most parts of the State the Transition 

 Zone is well timbered, and is the great source of supply of wood 

 and lumber in this State. The Yellow, Black and Sugar Pines, 

 White Fir, Cedar and Redwood are characteristic of this zone. 

 It contains a large number of species of birds and mammals, 

 though few, perhaps none, are limited to it, nearly all its species 

 being found in the adjoining zones, either above or below. Some 

 of the birds breeding principally in it are the Californian Wood- 

 pecker, Blue-fronted Jay, Californian Purple Finch, Violet-green 

 Swallow and Mountain Chickadee. 



The Transition zone in California may be divided into sev- 

 eral Faunas. The northeast part of the State, north of Honey 



