ABERTS TOWHEE 633 



Baccharis and in an introduced tree, Tamarix gallica. I believe that 

 a marked enlargement of habitat suitable for Abert's towhees has 

 occurred in southeastern California, as in Arizona, as a result of the 

 enlargement of irrigation facilities there in the past few decades. 



Nesting. — Abert's towhees of both subspecies nest most commonly 

 in willows, and three quarters of the 80 nests of P. a. aberti C. E. 

 Bendire (1890) found along Rillito Creek near Tucson, Pima County, 

 Ariz., were in plants of this type, particularly stumps. Mesquite 

 also appears to be regularly used as a nest site (Oilman, 1915; Bendire, 

 1890). P. a. aberti has also been recorded nesting in a Mexican elder- 

 berry shrub (Sambucus mexicana?) (Brandt, 1951); a species of ash 

 (Fraxinus sp.) (Bendire, 1890); Suaeda torreyana, umbrella tree 

 {Melia azedarach), and Zizyphus (M. F. Oilman, 1915); cottonwood 

 (F. C. Willard, 1923), and a mistletoe clump (Phoradendron sp.) in a 

 cottonwood (F. Stevens, 1878). P. a. dumeticolus is known to nest 

 in willows and mesquite and has also been recorded nesting in arrow- 

 weed and mistletoe clumps (Phoradendron sp.) probably located in 

 mesquite (van Rossem, 1911), and in such introduced plants as 

 pepper trees (Schinus molle) and orange trees near Palm Springs, 

 Riverside County, Calif. (M. F. Oilman, 1903). 



The nest of the Abert's towhee is rather bulky and loosely con- 

 structed (H. Brandt, 1951; H. Brown, 1903; and F. M. Bailey, 1928). 

 W. L. Dawson (1923) describes a typical one as follows: 



"A typical nest of this towhee is a bulky assemblage of weed-stems, 

 dead vines, bark-strips, green leaves; and, interiorly, coiled bark, 

 dried grasses, and horsehair. Bark is a favorite material, and I have 

 seen nests which contained nothing else. Occasionally, the taste 

 inclines to green grass, and the superstructure may be composed of 

 green, or recently dried, grass or leaves of a single sort. * * *" 



Bendire (1890) reported the dimensions of one nest to be: outer 

 diameter, 5.5 inches; overall depth, 4 inches; inner diameter, 3 inches; 

 inside depth, 2.5 inches. Brown's (1903) and Brewster's (1882a) 

 measurements of other nests of this species are comparable. 



The nests are placed off the gi'ound usually in low bushes. There 

 are several records of them placed in trees. Bendire (1890) found 

 one such along Rillito Creek in an ash fully 25 feet above the ground, 

 and Stevens (1878) found anotlier apparently along the Oila River 

 in a clump of mistletoe about 30 feet above the ground. Perhaps 

 the most unusual nest site on record was a cavity near the top of a 

 rotten cottonwood stump 12 feet above the ground (F. C. Willard, 

 1923). 



Eggs. — The clutch size for birds of both subspecies ranges from 

 two to four (C. K. Averill, 1933; F. M. Bailey, 1928; Bendire, 1890; 

 van Rossem, 1911; and M. F. Oilman, 1903), \nth the usual number 



