154 University of California Publications in Zoology [Vol.12 



branches with much cobweb; the rather shallow cavity (48mm. wide 

 by 17 deep) is lined with plant fibers, a few horse and cow hairs, and, 

 most liberally, with down feathers from the desert quail. In spite of 

 the absence of foliage on the tree, the nest was difficult to see even 

 from a distance of fifteen feet, because of its small height above the 

 branches on which it rested, and because its outer surface of gray 

 twigs blended admirably with the striately shredded bark of the dead 

 branches. One large branch extended above the nest, and gave partial 

 protection from the sun, and certain other small branches may have 

 helped some ; but the sitting bird must have been compelled to endure 

 the direct and intense sunshine a good part of the day. The nest was 

 discovered only by flushing the bird, which sat very closely, and 

 returned promptly when the intruder left the immediate vicinity. 

 Only the female was seen on or close to the nest. The far more bril- 

 liantly colored male remained at a distance of twenty to fifty yards 

 from the nest, selecting conspicuous perches on dead mesciuites, from 

 which it sallied forth after passing insects in ordinary flycatcher 

 fashion. It sang musically early in the morning before sunrise, the 

 song resembling somewhat that of the black phoebe, though of greater 

 length and not so loud. 



The nest and pair of birds were finally collected. The abdominal 

 surface area of the female was found to be conspicuously modified for 

 incubatory function, the skin being greatly thickened owing to the sub- 

 cutaneous vascular development. The male had no such feature. This 

 must have been an exceptionally early laying for the specias in this 

 vicinity, as other females taken showed no signs of breeding. 



The vermilion flycatcher was next noted on the Arizona side five 

 miles above Laguna, where it was fairly common on overflow land 

 among drowned and living cottonwoods and dead mesquites. On the 

 California side, four miles below Potholes, the species proved to be one 

 of the most numerous of the birds present. Here the valley widens out ; 

 much land is being reclaimed for farming, and intersecting irrigation 

 ditches supplied from the Laguna Dam conduct water throughout the 

 region. There is much wa.ste land as yet, and burning has killed many 

 of the cottonwoods. In this sort of locality the vermilion flycatchers 

 were found to be far more numerous than anywhere else; it would 

 appear that here is a native bird of the Colorado Valley which will 

 greatly augment in numbers with the settling of the region. 



A peculiarity of the bird which impressed me was that by apparent 

 preference it avoided green foliage, almost invarial)Iy perching on 



