WESTERN BLUEBIRD 267 



then flew away. A similar performance was seen a few days later; 

 the male seemed to flatten himself out for the female to mount. 



Nesting. — The nesting habits of the western bluebird do not differ 

 materially from those of its eastern cousin. The only two nests that 

 I have seen were in nowise out of the ordinary; one, found on May 14, 

 1911, near Tacoma, Wash., was in a cavity 10 feet from the ground 

 in a dead oak stub; it contained four eggs; the other, in Ventura 

 County, Calif., on April 7, 1929, was in an old hole of a California 

 woodpecker on the under side of a limb of a sycamore tree. The 

 nests were very simply and carelessly built structures of dry grass 

 and a few feathers. 



Referring to the Yosemite region, Grinnell and Storer (1924) 

 write: 



Old woodpecker holes are occupied when available, but failing to find one of 

 these the birds will use some naturally formed opening in a tree. The decay of 

 stubs of medium-sized branches often results in the formation of cavities in the 

 heart wood of an oak which are appropriate in form and size for use by the blue- 

 birds. * * * The nest found near Lagrange was in a blue oak on a hill top. 

 It was in a naturally rotted-out cavity at a height of 9 feet from the ground. 

 Distant but 17 inches in the same stub was the nest of a Plain Titmouse. The 

 bluebird's nest was 6^ inches below the rim of the opening and the sparse fining 

 upon which the 4 eggs lay consisted chiefly of dry foxtail grass. Another nest seen 

 at Smith Creek, east of Coulterville, was 14 feet above the ground in a black oak. 

 A natural cavity about 11 inches deep by 5 inches in diameter had been filled for 

 a depth of 4 to 5 inches with soft materials. Entrance was afforded to the nest on 

 two sides; on the one side was a hole about 2J4 inches in diameter, while there 

 was a much larger opening on the other side, so that the nest was easily visible 

 from without. 



In the Point Lobos Reserve, Monterey County, according to 

 Grinnell and Linsdale (1936), "all the nests were in cavities in pines 

 or pine stumps at heights ranging from five to forty feet, averaging 

 twenty-two feet. On the few occasions when material was seen being 

 carried to the nest, the female was doing the work. Usually, however, 

 the male was present and showed an interest in the procedure. Once 

 a male at a nest spent more time there than did the female, going in 

 and out and moving the materials. Several times a male was seen 

 to feed his mate." 



Western bluebirds are as easily encouraged to nest near our homes 

 in bird boxes as are their eastern relatives ; here they often meet serious 

 competition with violet-green swallows or western house wrens, but 

 the bluebirds are generally the masters of the situation; they can 

 defend their homes against such intruders and have been known to 

 drive out the swallows from their occupied nest. Where natural 

 cavities, woodpecker holes, or bird boxes are not available the blue- 

 birds will build their nests in any suitable cavity in a building, or 



