WHITE-THROATED SWIFT 313 



feathers; it measures about 4 inches in longest diameter and is hol- 

 lowed to a depth of about three-quarters of an inch; the eggs are 

 badly "flyspected," as seems to be frequently the case in nests of this 

 species. 



There is another interesting nest of this species in the collection, 

 perhaps a different subspecies, taken by Gerald B. Thomas in the 

 Coxcomb Mountains of British Honduras on May 27, 1906. It was 

 located in a cave, 50 feet from the ground, in a high cliff; it was 

 glued to the wall of the cave 10 feet from its mouth. The nest re- 

 sembles that of the chimney swift in shape and size, being almost 

 too small for the five eggs it contained; it is made of weed stems 

 glued together into a firm basket, and is profusely lined with small 

 feathers, dark brown and white, which look as if they might have 

 come from the parent bird. 



Wilson C. Hanna has published two interesting accounts (1909 

 and 1917) of the nesting habits of the white-throated swift in a 

 quarry on Slover Mountain in the San Bernardino Valley, Calif. 

 He describes the difficulties involved in securing the eggs, shows 

 photographs of the nests, and gives a series of measurements of both 

 the nests and the eggs. In his second paper, he says of the nests: 



Both the vertical and the horizontal cracks are used as nesting sites, but 

 with the exception of set no. 5, all that I took were from vertical cracks. It is 

 almost impossible to take nests from horizontal fissures without destruction 

 of the eggs and in the exception noted, a rock weighing at least 35 tons was 

 removed. * * * The location of nest no. 6 was rather unusual, being reached 

 by going into a vertical crack about three feet, then up eighteen inches, 

 then to the side about eight inches. ♦ * * 



Nests are constructed, for the most part, of chicken feathers and grasses 

 cemented together and to the rocks, probably by saliva. They vary in size 

 to suit the space between the walls of rock and are usually shallow and 

 narrow. * * * 



All nests that I have examined have been infested with numerous "bugs." 

 In the two nests where birds could be seen while incubating, the insects 

 could be observed crawling on the birds' heads. The eggs, in every case, were 

 more or less spotted as a result of the insects, depending upon how long they 

 had been in the nest. 



William C. Bradbury (1918) made some elaborate preparations 

 and, with the help of three young men, collected several sets of 

 eggs near Hot Sulphur Springs in Grand County, Colo. He writes : 



The cliffs where the birds were seen, bordering the Grand River, east of Sul- 

 phur Springs, are of a mixed lava formation, with some parts of hard, ringing 

 material, and others of cracked, crumbling formation, intermixed with seams 

 and deposits of soft lava ash, through which the river has cut its way in ages 

 past. The visible base of the cliffs is at the top of a steep slope of debris, 

 extending to the Grand River several hundred feet below. * * * 



The first available prospect, located by Niedrach through the presence of 

 excrement about eight feet up, and to which he was able to climb, was in a 



