374 BULLETIN 19 6, UNITED STATES NATIONAL MUSEUM 



region of Lower California in the lowland country. A pair were 

 building a nest in the immediate vicinity of my base camp at Mira- 

 flores in the latter part of May 1933, but they were rather shy about 

 divulging the actual nest site. However, after much watching, the 

 nest was found to be in the extreme top of a tall mahogany tree, and 

 since the birds were obviously building at this time, it was left undis- 

 turbed. On the day I broke camp, the extension ladder was set up to 

 its fullest length of 28 feet and that distance plus my six feet, plus arm 

 reach, fell short of reaching the nest by a good ten feet; so the nest was 

 cut down and lowered to me, only to find it contained but one egg. 

 I have never found a gnatcatcher nesting as high from the ground as 

 this one did." 



He took a set of three slightly incubated eggs near San Jose del 

 Cabo on May 23, 1933, which is now in the Doe collection at the 

 University of Florida. The nest was placed in a mesquite bush, 4 

 feet from the ground, and was made of fine fibers. These three eggs 

 measure 15.3 by 11.9, 15.3 by 11.4, and 14.5 by 11.4 millimeters. 



Since the above was written, the A. O. U. Committee has ruled in 

 its nineteenth supplement to the Check-list (Auk, vol. 61, p. 457) 

 that this bird is synonymous with P. m. margaritae, but it seems best to 

 include the above account as a matter of historical record. 



POLIOPTILA MELANURA CALIFORNICA Brewster 



BLACK-TAILED GNATCATCHER 



HABITS 



Contributed by Robert S. Woods 



Although frequenting the environs of some of the most populous 

 districts of the West, the black-tailed gnatcatcher remains one of the 

 least familiar of North American birds. For some reason this species 

 is localized and comparatively few in numbers, while the western 

 gnatcatcher, apparently with no superior endowments, is widespread 

 and numerous. 



Formerly classified as a separate species (Polioptila californica) , this 

 form is now regarded as a subspecies of the plumbeous gnatcatcher, 

 but it is easily distinguishable from the latter in the field by its decidedly 

 darker body coloration. The dividing line between their respective 

 territories lies across San Gorgonio Pass and along the higher mountain 

 chain of southern California. The range of the present subspecies 

 extends from Ventura southward into northwestern Lower California. 



Semidesert valleys and lower slopes covered with a low and often 

 scattered growth of shrubs are the home of the black-tailed gnat- 

 catcher, and few land birds confine themselves so rigidly to their 

 characteristic habitat. Suitable conditions are found on gravelly 



