PLUMBEOUS GNATCATCHER 369 



is decorated with a very few lichens, all these materials being over-wrapped and 

 kept in place by a nearly invisible tissue of spider-web. The interior is lined 

 with fragments of silky cocoons and a few feathers. The other nest, which was 

 placed in the fork of a small tree about ten feet above the ground, and which is 

 essentially similar to the specimen just described, save that it has no lichens 

 whatever, measures externally 2.15 in diameter by 2.10 in depth; internally, 1.40 

 in diameter by 1.50 in depth. Both nests are smaller and more compact than 

 any nests of P. caerulea in my collection. 



There is a set of eggs in the Doe collection, taken by J. Stuart 

 Rowley at Miraflores on May 8, 1933 ; the nest was saddled on a branch 

 of a palo bianco tree, 20 feet above ground. A nest in the Thayer 

 collection, taken by W. W. Brown near La Paz on June 25, 1908, was 

 placed between two upright stems of a bush, about 5 feet from the 

 ground. The construction of this nest is similar to that of the nest 

 described above; there are no lichens on it, but it has a decidedly 

 gray appearance. 



The eggs of the San Lucas gnatcatcher are similar to those of the 

 species elsewhere. The measurements of 32 eggs average 14.5 by 11.2 

 millimeters; the eggs showing the four extremes measure 15.6 by 11.8, 

 14.3 by 11.9, 12.9 by 11.2, and 13.6 by 10.6 millimeters. 



POLIOPTTLA MELANURA MELANURA Lawrence 



PLUMBEOUS GNATCATCHER 



HABITS 



The type race of this species is the desert form that inhabits the 

 arid and semiarid regions of the southeastern United States and 

 northern Mexico. The plumbeous gnatcatcher, like many other 

 desert forms, is much paler, especially on the dorsum, than its near 

 relative and neighbor, the California black-tailed gnatcatcher, and it 

 has more white in the tail and usually more on the lores and sides of 

 the head. 



The favorite haunts of this gnatcatcher are in the thorny thickets of 

 mesquites or in the rank growths of saltbush on the southwestern 

 deserts. Van Tyne and Sutton (1937) say that, in Brewster County, 

 Tex., both this and the western gnatcatcher are common, "but the 

 Plumbeous is a bird of the river banks and low country, while the 

 Western Blue-gray is a bird of the mountains. We found the Plum- 

 beous especially abundant in the dense thickets of mesquite in the 

 ravines and along the Rio Grande." Mrs. Bailey (1902) says: "The 

 small bluish figure of plumbea is a familiar sight in the brushy canyon 

 mouths of the Guadalupe Mountains in Texas and in the orchard-like 

 juniper and pifion pine tops of the mountains." We found it fairly 

 common in the low, arid valleys and dry brushy washes in southern 

 Arizona, nesting in the thorny bushes. 



