ee 
aes el GRINNELL, The California Thrasher. 433 
apparent “shyness’’ of the Thrasher — by the ease with which it 
eludes close observation, or, if thoroughly alarmed, escapes detec- 
tion altogether. For this protective effect the bird is dependent 
upon appropriate cover, the chaparral, and upon its ability to 
co-operate in making use of this cover. The Thrasher has strong 
feet and legs, and muscular thighs, an equipment which betokens 
powers of running; the tail is conspicuously long, as in many run- 
ning birds; and correlatively the wings are short, rounded, and 
soft-feathered, indicating little use of the flight function. The 
colors of the bird are non-conspicuous — blended, dark and light 
browns. The nests of the Thrasher are located in dense masses 
of foliage, from two to six feet above the ground, in bushes which 
are usually a part of its typical chaparral habitat. In only excep- 
tional cases is the chosen nesting site located in a bush or scrubby 
tree, isolated more or less from the main body of the chaparral. 
These various circumstances, which emphasize dependence upon 
cover, and adaptation in physical structure and temperament 
thereto, go to demonstrate the nature of the ultimate associational 
niche occupied by the California Thrasher. This is one of the 
minor niches which with their occupants all together make up the 
chaparral association. It is, of course, axiomatic that no two 
species regularly established in a single fauna have precisely the 
same niche relationships. 
As a final statement with regard to the California. Thrasher, 
we may conclude, then, that its range is determined by a narrow 
phase of conditions obtaining in the Chaparral association, within 
the California fauna, and within the Upper Sonoran life-zone. 
