156 BULLETIN 17 9, UNITED STATES NATIONAL MUSEUM 



walls against which to place their nests, and these sites must be within carry- 

 ing distance of some source of the mud used in nest construction. Such sites 

 are widely and irregularly scattered. The building of bridges over creeks and 

 the maintenance of stock barns with watering troughs near by have probably 

 increased the population of these birds in the country as a whole. 



The following account of nesting sites chosen by black phoebes in 

 the vicinity of Fresno, Calif., together with dates of nesting, by 

 John G. Tyler (1913), is typical of descriptions by various observers 

 in both California and Arizona: 



Nests of these birds are sometimes fastened to the walls of deserted cabins, 

 and occasionally a pair will build in an old well if they can gain entrance, 

 such nests being from six to fifteen feet below the surface of the ground. The 

 most common nesting sites, however, are the large stringers of bridges, where 

 the nest is securely fastened above the water. I have never known this species 

 to choose a place where there would be support for the bottom of the nest, as 

 the Eastern Phoebe is said to do. Our bird attaches its wall pocket to the ver- 

 tical surface of a plank, and so securely is it fastened that it will often break 

 apart rather than give way. This species often nests on the faces of rocks in 

 the hills, but such sites are almost entirely wanting in the Fresno district. I 

 have found one or two nests fastened to the partly dead trunk of some large 

 tree, but it is safe to say that nine out of ten birds choose the protection 

 afforded by bridges, where mud is easily secured, and horsehairs as well, for 

 these two ingredients enter largely into the construction of the nest. * * * 



I have found eggs nearly ready to hatch on April 5 and fresh ones June 15, 

 so the nesting period may be said to extend from March 1 to July 1, with 

 probably two broods reared in a season, in some cases at least. 



Several other writers have mentioned wells as nesting sites, 4 or 5 

 feet below the surface. As an instance of the birds' fearlessness in 

 attending their nests despite disturbances, Florence A. Merriam 

 Bailey (1896) wrote: "April 30, 1898, I found three eggs in the nest 

 of a Black Phoebe five feet down in a deserted well. Before the eggs 

 hatched, a pump was put down the well and water pumped up every 

 day, but the birds did not desert the nest." Illustrating the same 

 characteristic, Milton S. Ray (1906) says, "About Visalia I noticed 

 about half a dozen nests with eggs placed in sluice boxes through 

 which the water coursed uncomfortably close to the mud-made domi- 

 cile." 



John McB. Robertson (1933) describes the unusual occurrence of a 

 black phoebe's nest in a willow tree leaning over a watercourse near 

 Artesia, Calif. : "One tree, about eight inches in diameter, had a dead 

 limb on its lower side extending downward at a sharp angle, and on 

 the end of this was a typical mud nest of the Black Phoebe, contain- 

 ing two young birds about a week old. The parent birds were near- 

 by. Shreds of willow bark had been used with the mud and fringed 

 the outside of the nest ; the lining was of bark and hair. The nearly 

 horizontal trunk of the tree formed a shelter about six inches above 

 the nest which was about three feet from the water." The black 



