GREEN-TAILED TOWHEE 549 



Calif.), and 4,350 feet (Fremont National Forest, Colo.) above sea 

 level; the highest point was 10,500 feet (San Francisco Mountains, 

 Ariz.). A median or average elevation based on this series of records 

 is about 7,300 feet. Southerly populations tend to breed at higher 

 elevations than more northerly ones do. Although present in much 

 of the transition zone, this brush inhabitant is perhaps most character- 

 istic of the Canadian zone, as was graphically illustrated for the 

 Yosemite region by J. Grinnell and T. I. Storer (1924). The range 

 also extends well up into the Hudsonian zone in areas such as the 

 San Francisco Mountains, where R. Jenks (1934) found that "these 

 birds inhabit the mountain willow and wild gooseberry thickets on 

 the borders of alpine meadows, from altitudes of 8,300 up to 10,500 

 feet." 



Especially prominent among shrubs that characterize its breeding- 

 season habitats are sagebrush (Artemisia), deerbush and snowbush 

 (Ceanothus) , wUd rose and spiraea (Rosa and Spiraea), manzanita 

 (Ardostaphylos) , waxberry {Symphoricarpos) , and chokecherry 

 (Prunus virginianus) . Other plants, either less widespread or less 

 important for the green tail, are mountain mahogany (Cercocarpus) , 

 gooseberry (Ribes), antelope brush (Purshia), ninebark (Physocarpus) , 

 serviceberry (Amelanchier) , and ocean-spray (Flolodiscus) . Fre- 

 quently open stands of pifion and juniper are interspersed in the 

 chaparrallike vegetation or ponderosa pme forms a partial canopy above 

 it. This species' habitat and niche, as found in California, are suc- 

 cinctly described by J. Grinnell and A. H. Miller (1944): 



"* * * Forest is avoided; only scattered trees within the brushland are 

 tolerated, but they may be used as song posts. The brush cover is 

 typically low (2 to 4 feet) and spreading, affording runways between 

 plants and underneath the foliage. Within forested areas, the places 

 occupied are comparatively diy and well insolated; in the Great Basin 

 region the lower, warmer flats are avoided even though grown to 

 sagebrush. The sphere of activity is low, foraging taking place on 

 the ground in the leaf litter and in the tangle of branches.* * *" 



Spring. — W. W. Cooke (1914) says: "From its winter home in 

 northern Mexico and along the border of the United States, the 

 Green-tailed Towhee moves slowly northward, occupying more than 

 two months — late February to early May — in passing across the less 

 than a thousand miles from the northern lunit of the winter home to 

 the northern boundary of the breeding range," 



Many of the migrants triclde into southern parts of California, 

 Arizona, and New Mexico in the first week in April. Representative 

 arrival dates for Silver City, N. Mex., and Carson City, Nev., are 

 April 12 and 25, respectively, while an average early date (based on 

 data from 7 years) for Laramie, Wyo., is May 11. In California, 



