PLUMBEOUS GNATCATCHER 371 



rarely an egg is almost immaculate. The measurements of 40 eggs 

 average 14.1 by 11.1 millimeters; the eggs showing the four extremes 

 measure 15.2 by 11.2, 14.5 by 11.5, 12.2 by 11.0, and 13.1 by 10.6 

 millimeters. 



The plumbeous and the black-tailed gnatcatchers are so much alike 

 in all their habits and characteristics, due allowance being made for 

 the difference in environment, that the excellent life history of the 

 latter contributed by Mr. Woods will suffice for the former. 



As the plumbeous and the western gnatcatchers are sometimes 

 both found in the same region in winter, and as the former does not 

 show its black cap at that season, there is a chance of confusing the 

 two species in their winter haunts. However, Ralph Hoffmann 

 (1927) remarks: "The darker gray of the Plumbeous Gnatcatcher 

 and the small amount of white in the tail when spread are helps to 

 identification, but the call notes are often the only sure distinctions. 

 The call of the Plumbeous Gnatcatcher is a series of two or three 

 short notes, chee chee chee, unlike the single emphatic pee of the 

 Western. The song of the Plumbeous Gnatcatcher is a slight tsee- 

 dee-dee-dee-dee, suggesting a chickadee." 



Dr. Friedmann (1929 and 1934) mentions several cases where this 

 bird has been victimized by cowbirds. And Mr. Rowley tells me 

 that "along the Colorado River area, cowbirds parasitize the nests 

 of these birds rather abundantly," and he has "found a female sitting 

 on three eggs of a cowbird and none of her own, with many nests 

 containing one or two cowbird eggs." 



DISTRIBUTION 



Range. — Southwestern United States and northern Mexico; non- 

 migratory. 



The gnatcatchers of the melanura group breed north to southern 

 California (Santa Barbara, Yermo, Daggett, and Resting Spring); 

 southern Nevada (Las Vegas and Bunkerville) ; northern Arizona 

 (Beale Spring, Big Sandy Creek, Fort Whipple, and Keam Canyon) ; 

 western and southeastern New Mexico (Gallup and Fort Wingate; 

 Carlsbad and the Guadalupe Mountains); the western extension of 

 Texas (Frijoles, Marathon, and Chisos Mountains) and the Rio Grande 

 Valley (Lozier, Laredo, and Brownsville) ; with records of its occurrence 

 at Corpus Christi and San Antonio. East to extreme southern Texas 

 (Brownsville) and Tamaulipas (Jaumave). South to Tamaulipas 

 (Jaumave) ; central Nuevo Le6n (Monterrey) ; southern Coahuila (San 

 Pedro) ; central Chihuahua (Santa Eulalia and Chihuahua) ; central 

 Sonora (Moctezuma and Guaymas) ; and Lower California (Cape San 

 Lucas). West to the Pacific coast of Lower California (Cape San 

 Lucas, Todos Santos, Santa Margarita Island, San Juanica Bay, and 



