500 ANIMAL LIFE IN THE YOSEMITE 



Like other hunting birds which feed exclusively on flying insects these 

 swallows spend most of the daylight hours on the wing. At times they 

 come to rest on a wire or other convenient perch where they are wont to 

 spend some minutes in dressing and preening the long flight feathers of 

 the wings. Depending as they do so completely on these organs for gain- 

 ing their livelihood it is not to be wondered at that the swallows take 

 exceedingly good care of their wings. In consequence of their care of 

 their plumage and of the open nature of their forage area, the primary 

 feathers do not show anywhere near so much wear as do the flight feathers 

 of birds which inhabit shrubbery, grass or trees, whose feathers come in 

 direct contact with these objects. 



The Barn Swallow arrives in the Yosemite region during March and 

 lingers until late summer or even early fall. Six individuals, including 

 some young of the year already on the wing, were seen near Merced Falls 

 on August 17, 1915. About 12 birds of this species were observed near 

 Grant Lake, east of the Sierras, on September 14, 1915. 



At Mono Mills on June 19, 1916, a nest of the Barn Swallow was found 

 at the side of an old cellar which had once been used for the storage of 

 potatoes. No bridge beams being available the birds had made use of 

 the one site most nearly like that usually chosen. The nest contained five 

 eggs in which incubation was well advanced. 



In Bower Cave on July 18, 1920, a pair of these swallows was seen to 

 enter a dark cavern at the bottom of the pit, skimming close over the 

 water. One bird was carrying a fluffy white chicken feather which could 

 be followed by the eye after the bird itself had become invisible in the 

 gloom. Nest construction was probably under way even though, seasonally, 

 the date was late. On July 20, 1920, near Dudley, 6 miles east of Coulter- 

 ville, a nest containing two fresh eggs was discovered in a mining shaft 

 30 feet below the surface of the ground. 



The Barn Swallow, like the Cliff Swallow, constructs a mud nest. But 

 the nest of the former is open-topped, like a phoebe's, instead of retort- 

 shaped, and has more straws and feathers incorporated into it. 



Tree Swallow. Iridoprocne bicolor (Vieillot) 



Field characters. — Body size about that of Linnet or Junco; tail nearly square-ended. 

 Upper surface of body black with a steely blue iridescence; -whole under surface white; 

 no white on rump. Voice: Faint single notes, sect, sometimes given several together to 

 form a weak twitter. 



Occurrence. — Sparse summer visitant. Eecorded only in vicinity of Snelling and 

 Lagrange, and, east of the mountains, at Mono Lake Post Otfiee. Usually near standing 

 water. In pairs or loose companies. 



