BLACK-TAILED GNATCATCHER 375 



washes along watercourses, as around Azusa and Claremont in Los 

 Angeles County, and in various parts of San Diego, Riverside, and 

 San Bernardino Counties. A. C. Bent (MS.) and Dr. Louis B. 

 Bishop also encountered this species, together with Bell's sparrow, 

 near Norco, on "low, rolling hills covered with an open growth of 

 low bushes, chamise, white sage, golden yarrow and wild buckwheat." 

 Even in the most favorable situations the black-tailed gnatcatcher 

 is not abundant, and, as it does not range far in search of food, it 

 might be looked for in vain through a period of years in any given 

 locality. 



Measurements indicate that this species closely rivals the bush tit 

 for the distinction of being the smallest North American passerine 

 bird. 



Nesting. — As its nesting sites, the black-tailed gnatcatcher chooses 

 small or medium-sized bushes rather than large ones. Eight nests 

 discovered at Azusa by the present writer, during three different 

 years, were placed at heights of 2 to 3 feet. Four were in buckthorn 

 bushes (Rhamnus crocea), two in laurel sumac (Rhus laurina), one 

 in a clump of cactus and weeds, and the last in a shrubby composite 

 (Ericameria pinifolia). These locations afforded varying degrees of 

 concealment, one of the buckthorns being so densely branched that 

 the nest could hardly be discerned from any point outside the bush, 

 while those in the sumacs could easily be seen from a distance. 



Descriptions of nesting sites in other districts differ in minor details. 

 Wilson C. Hanna (1934) mentions a nest 4 feet from the ground, near 

 the top of a black sagebush on a dry hillside near Riverside. Mr. 

 Bent (MS.) saw one near Claremont "about 2 feet up in a small 

 branching cactus growing in a clump of chamise, on a dry, dusty 

 chamise-covered flat." Probably the earliest description of the 

 black-tailed gnatcatcher's nest is that of Bendire (1888) : 



This gnat-catcher was first described by Mr. William Brewster, from specimens 

 collected by Mr. F. Stephens near Riverside, * * * Cal., March 28, 

 1878. * * * * 



The nest of P. Californica, like that of P. plumbea Baird, from Arizona 

 Territory, differs radically in structure from that of its eastern relative, P. caerulea 

 (Linn.), wMch is too well known to ornithologists to require description. It 

 lacks entirely the artistic finish of the lichen-covered structure of the former, and 

 resembles more in shape certain forms of the nest of the Summer Yellow Warbler, 

 Dendroica aestiva (Gml.), and the American Redstart, Setophaga ruticilla 

 (Linn.) 



The nest is cone-shaped, built in the forks of a small shrub, a species of ma- 

 hogany, Coleogyne ramosessima (Tore.) I think, only 2 feet from the ground, 

 and it is securely fastened to several of the twigs among which it is placed. Its 

 walls are about half an inch in thickness. The material of which the nest is 

 composed, is well quilted together and makes a compact and solid structure. 



