158 BULLETIN 19 7, UNITED STATES NATIONAL MUSEUISI 



is especially common in the Great Valley of California and in coastal 

 southern California. To the northward in eastern Oregon and Wash- 

 ington and the northern part of the Great Basin it occurs rather 

 sparsely in juniper and sagebrush land. Aggressive, vigorous, and 

 decisive in its actions, and contributing strident bursts of sound and 

 also varied melodic trills to the auditory ensemble, it is likely to be one 

 of a person's first bird acquaintances in those regions where it flour- 

 ishes. Shrikes are drawn to roadsides by desirable perches on fences 

 and power lines, and in such places their conspicuous foraging actions 

 and their interesting butchering habits are easily watched, as is also 

 their nesting activity, which centers in isolated clumps of trees or tall 

 bushes. Through the spring and early summer the wheedling cries 

 of large families of hungry young shrikes are an ever-present sound, 

 typical of the parched plains and gently sloping hills of a lowland 

 California countryside. 



Loggerhead shrikes hunt by watching from fixed positions, and long 

 unobstructed views are required. Food typically is taken on the 

 ground and is seen from above. These instinctive methods demand that 

 the bird live in the open but where there are good lookout posts. 

 Dense brush and continuous woodland or forest would not permit 

 normal operations. Further than this, these shrikes seem to do best 

 where there is little or but moderate rain and fog, especially in the 

 summer season. Agricultural developments within the range of the 

 California shrike have probably favored this bird by providing trees 

 in open plains areas without diminishing significantly the exposed 

 ground surface where they hunt. 



North of California, shrikes are largely migratory, but south of 

 latitude 40° their populations are resident. Migration is never a 

 conspicuous affair in this bird, although on the Colorado Desert Cali- 

 fornia shrikes winter regularly with Sonora loggerhead shrikes, 

 Lanius ludovicianus sononensis, which are permanently resident there. 

 Where I have most closely watched California shrikes in Contra Costa 

 County, Calif., and in the Lower San Joaquin Valley, no movements 

 of more than local type have been detected. 



Territory. — Unlike many passerine birds, shrikes display territorial 

 behavior throughout the year. Late in summer and in fall, resident 

 California shrikes are completely solitary, and males and females de- 

 fend feeding territories. The annual territorial cycle then may be 

 said to begin at the close of the breeding season early in July when 

 family groups are disintegrating. Typical was the action of an adult 

 male observed on July 3, 1929, at Firebaugh, Fresno County. Two 

 young were pursued seemingly in an endeavor to chase them from the 

 vicinity. The adult sang at frequent intervals and attempted to at- 

 tack three young captive shrikes that I had in camp. No other adult 

 shrike was permitted to come about the singing posts of this male. 



