ARIZONA SULPHUR-BELLIED FLYCATCHER 101 



the material and builds the nest, without any help from the male, 

 except that he follows her about and perches near the nest hole, giving 

 her encouragement with the nearest approach to pleasing notes that 

 he can produce. Mr. Willard told me that the busiest time for nest 

 building is early in the morning, about 6 o'clock, but that the work 

 goes on spasmodically all day ; it took about eight days to build one 

 of the nests that he watched. He said that the female collected 

 twigs from a walnut tree, breaking them off, but the midribs of the 

 walnut leaves were picked up from the ground. 



The nesting habits of the Central American race seem to be very 

 similar to those described above. Mr. Skutch says in his notes : "The 

 nest is placed in a cavity in a tree, preferably in a dead trunk standing 

 isolated in a clearing. An old woodpecker's hole may be used; but 

 at other times the bird prefers an open niche or hollow formed by 

 decay, and scarcely sheltered from the sky. The nests I have seen 

 have varied in height from 11 to 45 feet. The nest is built by the 

 female alone ; but the male is most attentive to her while she works, 

 frequently following her on her trips to fetch material, and some- 

 times picking up fine twiglets with which he toys, then drops." He 

 watched a female that seemed to have diflBculty in deciding which 

 of two available cavities to occupy and was filling both with twiglets 

 alternately. "'When she flew toward one or the other of the cavities 

 that she was filling, her mate often hurried ahead of her and came 

 to rest on the sill of the doorway, or clung to some convenient pro- 

 jection close beside it, where he sang a low, hurried, twittery, somewhat 

 harsh-voiced song, while his partner arranged the material within." 



Eggs. — The three or four eggs laid by the sulphur-bellied fly- 

 catcher are very handsome and richly colored. The eggs are ovate 

 and only slightly glossy when fresh. The ground color varies from 

 white to rich creamy buff. They are profusely spotted and blotched, 

 usually over the entire surface, with rich reddish browns, "chestnut," 

 "auburn," or "liver brown," with underlying spots of different shades 

 of "Quaker drab" or "lavender"; Bendire (1895) mentions one that 

 is marked with dark "pansy purple." The measurements of 26 eggs 

 average 25.9 by 19.0 millimeters; the eggs showing the four extremes 

 measure 27.9 by 19.3, 26.0 by 19.9, and 24.0 by 18.0 millimeters. 



Toij,ng. — Mr. Skutch (MS.) writes: "Once in Guatemala I stuck 

 in the entrance of a low nest a twig that bore on its exposed end a 

 little wad of cotton soaked with vermilion paint. The flycatchers 

 succeeded in pulling it out and carrying it away, but while doing so 

 both of the pair stained with vermilion the pale yellow plumage 

 of their under parts. The female acquired the heavier marks, by 

 which she could readily be distinguished from her mate. I watched 

 this nest from concealment for nearly seven hours, during which 



824726—42 8 



