VERTEBRATE FAUNA OF THE PACIFIC COAST 

 colored species of coyote, and also bats of a sur- 

 prisingly large variety, again an evidence of the 

 abundance of insect life in proportion to the scant 

 vegetation. 



Birds of the Lower Sonoran deserts are few in 

 individuals save on the bottomlands along such 

 streams as the Gila, Colorado and Mohave. Here, 

 where the deciduous mesquite, cottonwood and wil- 

 low furnish directly or indirectly abundance of 

 food and shelter, birds are plentiful and strikingly 

 different as a rule from those familiar to the visitor 

 coming from either the Atlantic Coast or the Paciiic. 

 Ihe titmouse-like verdin, Abert towhee and crissal 

 thrasher are resident the year through, while the 

 Lucy warbler, plumbeous gnatcatcher, Cooper tana- 

 ger, white-winged dove, Sonora yellow warbler, and 

 a score of other species are but summer visitants. 

 Out on the desert proper, far from water, one may 

 find here ana there a pair of Say phoebes nesting in 

 some rocky ravine or mine tunnel; rock wrens asso- 

 ciate with the chuckawallas in the bare broken rock 

 masses; cactus wrens build their conspicuous cov- 

 ered nests in clumps of the most prickly cactus 

 without apparent inconvenience to themselves but 

 safe from ordinary predators; and, finally, we must 

 mention that elusive songster of the desert wastes, 

 the LeConte thrasher. A veritable will-o-the-wisp 

 by reason of its sand-toned color and extreme wari- 

 ness, it was for many years considered the rarest 

 of southwestern birds. Its clear whistled notes are 

 to be heard in the cool of the mornings ringing out 

 over the desert; but days may pass before the most 

 alert collector has gained even a glimpse of the bird 

 itself. From the transcontinental trains are fre- 

 quently seen a pair of ravens, scavengers that have 

 learned to follow back and forth along the railroad 

 tracks gleaning food from the garbage thrown from 

 the trains. Strange as it may seem, the desert avi- 

 fauna includes also several species of woodpeckers, 

 most of which excavate their homes in the trunks 

 of the giant cactuses. One little ladder-backed 

 woodpecker, however, ranges far over the desert, 

 foraging among bushes and digging out its nesting 

 cavity in the stem of some yucca or palo verde, not 

 infrequently in the hard wood of a telegraph pole. 



Perhaps the most instructive bits of any one of 

 the routes to the Pacific, as far as the zoogeographer 

 is concerned, lie at those points of mingling or sep- 

 aration, where desert and Pacific faunas meet. Such 

 points are the San Gorgonio, Soledad and Tehachapi 

 passes on the Southern Pacific, and El Cajon Pass 

 on the Santa Fe. It is to be hoped that in his travels 



112 



