Vertebrate Fauna of the Pacific Coast 

 great diversification locally in temperature and 

 humidity. Within the single state of California 

 the effects of this climatic diversity on the animal 

 life are abundantly illustrated. Terrestrial verte- 

 brate animals at home within the boundaries of the 

 state are representative of the life of the far North 

 and of that of portions of Mexico. Marine life, of 

 both cold and warm waters, is also abundantly rep- 

 resented. The result is a very large number of 

 species and higher groups in proportion to the size 

 of the area. Within the state of California alone 

 there have been detected up to the date of writing 

 this chapter a total of 361 species of mammals, 539 

 of birds, 76 of reptiles, and 24 species of amphib- 

 ians. It may be stated with confidence that no other 

 state in the Union, or even contiguous pair of 

 states, possesses so many species as California, un- 

 less Texas proves more prolific than present knowl- 

 edge indicates. 



It is true that visitors to California have com- 

 plained of the apparent lack of bird life as com- 

 pared with their home localities on the Atlantic 

 Coast or in the Middle West. There is doubtless 

 some basis for this impression locally in California, 

 to be accounted for on the grounds of sparse vegeta- 

 tion, lack of water, or cultivation by such methods 

 as leave little waste ground where birds can forage. 

 Some one has suggested, too, that many native birds 

 on the Pacific Coast are still adjusting themselves, 

 though slowly, to the conditions of cultivation and 

 settlement, and that before many more years have 

 elapsed our races of wrens, martins, and bluebirds 

 will be as familiar about our California homes as 

 are their counterparts in the East. Our mammal 

 population certainly includes an abundance of indi- 

 viduals as well as of species. Even the most arid 

 parts of the great deserts, of forbidding aspect, pos- 

 sess a phenomenal population. In order to appre- 

 ciate this numerical feature the enquirer must resort 

 to systematic trapping; for the great majority of our 

 mammals are strictly nocturnal in their habits. 



It will probably prove most profitable to the 

 reader who is privileged to journey in the West if 

 we present an outline, though of necessity severely 

 brief, of the more conspicuous elements in some of 

 the faunal subdivisions of the country likely to be 

 traversed. 



In considering the distributional areas of west- 

 ern North America, it may be explained that the 

 term life zone is applied to the unit of largest area. 

 Six of these life zones are recognized north of the 

 Mexican line. These are, enumerated from south to 



105 



