WESTERN HOUSE WREN 143 



from the ground ; both of these were at an elevation of about 8,000 

 feet. F. Seymour Hersey mentions in his Manitoba notes a nest that 

 was built in the skull of a moose, with horns attached, that was hung 

 up in a tree back of an Indian's house. 



The commonest and most primitive nesting sites are in natural cav- 

 ities or crevices in stumps, or in fallen or standing trees, including old 

 woodpecker holes; such sites are usually at no great height above 

 ground, generally below 10 feet ; heights of 20 or 30 feet are unusual. 

 The highest nest I find recorded is reported by Grinnell, Dixon, and 

 Linsdale (1930) in the Lassen Peak region: "The bird carried twigs 

 to the top of one of the tallest of the dead yellow pine stubs of that 

 vicinity, fully fifty meters above the ground. The bird each trip moved 

 upward by a well defined route, flying from limb to limb as though 

 moving up a staircase. By the time the wren reached the nest in a 

 crack at the top of the stub, the observer on the ground could scarcely 

 trace its movements." They found two other nests that were ten 

 meters up in similar stubs, as well as others at more normal heights. 



Nests have been found in cavities in rocks and crevices in caves. 

 Ridgway (1877) mentions some interesting nests, observed in Nevada : 

 "One nest was placed behind a flat mass of a small shrub {Spiraea 

 caespitosa) , which grew in moss-like patches against the face of a cliff. 

 Another one, and the only one not concealed in some manner, was built 

 in the low crotch of an aspen, having for its foundation an abandoned 

 Robin's nest. It consisted of a somewhat conical pile of sticks, nearly 

 closed at the top, but with a small opening just large enough to admit 

 the owner. Including its bulky base, the total height of this structure 

 was about 15 inches." 



About human habitations bird boxes are eagerly accepted where 

 these are available ; otherwise, any nooks or crannies on or in buildings 

 are used, or any tin can, box, pail, crate, empty stove pipe, or old hat 

 or coat left hanging in a shed will do. Some such interesting nests 

 have been described. Dr. W. W. Arnold (1906) shows a photograph 

 of a huge nest: "A shallow box afforded the foundation of the nest, 

 which was constructed of the smaller twigs of the scrub oak and built 

 into the form of a pyramid. Many of the twigs were forked and skill- 

 fully locked together, forming a very rigid structure, 12 inches wide at 

 the base, 51/^ inches across the top, and 16 inches high." 



The nests are constructed mainly of small sticks or twigs, or rather 

 more accurately, this material is used to fill up, or to attempt to fill up, 

 the cavity adopted ; in some cases an immense amount of such material 

 is brought in, sometimes enough to fill a bushel basket. The lining con- 

 sists mainly of feathers, often in great profusion and of many colors. 



Many nests contain more or less snakeskin, and some are largely lined 

 with it. Dix Teachenor (1927) reports that out of 30 nests of western 

 house wrens examined by him and Harry Harris, near Kansas City, 



