The Gnatcatchers of Southern California 



75 1 A WESTERN GNATCATCHER {Polioptila caerula obscura) 

 753 black-TAIEED GNATCATCHER {Polioptila californicd) 



SMALL and perky, blue-gray and black, almost the color of the sage ana 

 chemise brush in which they constantly make their home, incessantly 

 noisy, there is no bird of all the Southwest more easily heard and less easily 

 located than either one of these busy insect-hunters. Both are residents of 

 the sections they inhabit, but both are what might be called "local 

 migrants," frequenting at one time of the year the low foothills and at 

 another the slopes of the higher mountains. High or low, however, they 

 most commonly frequent brush-grown washes, " California rivers," dry as a 

 bone all summer and grown up to a mass of thick shrubbery, about waist 

 high, and in some cases almost impenetrable. Here the incessant twit, twit 

 of one or both of a pair of Gnatcatchers will be heard for at least every 

 hundred feet of progress one makes. If the way be particularly easy, so that 

 the observer makes little noise, the biids will come boldly about him, keep- 

 ing up an incessant chatter, perhaps a trifle noisier if the nest be near, though 

 they seem to have little idea of concealing that home by silence as is the 

 practice of so many small birds. 



These homes are built in the forks of the branches of any suitable shrub, 

 sometimes several feet from the ground, more often a yard or less, and are 

 perfect little cups of softly felted plant down, fibres from the inner bark of 

 such trees and dead cactus plants as they may be able to find, and an occa- 

 sional horsehair, though this lining is not often resorted to save in very bar- 

 ren districts where plants bearing any sorts of down are scarce. There seems 

 to be little difference in the nest built by the two species, nor in the mater- 

 ials used. But the birds are so well distinguished that the collector has little 

 trouble in correctly identifying the nests found. The most common of the 

 two is, of course, the Western Gnatcatcher, and nine out of ten of the sets 

 taken in this end of the state belong to that variety. It is very unreasonable 

 in a choice of nesting sites, selecting one season a well-wooded bit of wash, 

 and the next an apparently barren and unsuitable place, while all around are 

 much better situations — from a human standpoint. 



