CALIFORNIA BIRD STUDIES 



257 



mon, among them being numbers of Desert Song Sparrows, 

 which, with haunts not unlike those our Eastern Song Spar- 

 row often frequents, is still the palest form among some 

 twenty races of this plastic species ; evidently it owes its 

 colors to the direct action of the aridity of its environment, 

 and not to a natural selection which has brought it into a 

 fancied harmony with its immediate surroundings. 





Tree Yuccas at Hesperia 



To the westward one should pause on the borders of the 

 lately formed and now disappearing Salton Sea, in which 

 White Pelicans have taken possession of an island ; or, still 

 farther west, to observe the effects of irrigation on bird as 

 well as plant-life of the Imperial Valley. The desert range 

 is here crossed through the San Gorgonio Pass, where the 

 rush of wind from the Pacific to the heated deserts creates 

 a sand-blast from which the telegraph poles must be pro- 

 tected. 



