CALIFORNIA SHRIKE 177 



impaled objects does occur it is due to the habitual return of the 

 shrike to a successful impaling station because of the facilities avail- 

 able there for the ready handling of the prey, not because of a desire 

 to store or concentrate food. In inspecting numerous shrike impal- 

 ings I find that where abundant impaling situations, such as barbed- 

 wire fences, are at hand, the unfinished meals of shrikes are distributed 

 along such fences at considerable intervals. Concentrations of im- 

 palings such as often do occur probably result from a scarcity of 

 impaling facilities in a territory. 



A considerable portion of the deserted impalings consists of parts 

 of animals that would seem to be less desirable as food. Jaws of 

 lizards, the hard heads of Stenopclmatus, partly picked bones of mice, 

 and the wings and tails of birds are samples of deserted parts that 

 appear on the average more abundantly than do soft-bodied insects 

 and the flesh of vertebrates. Recent, although deserted, impalings 

 do not appear in the same abundance at all times of year in California. 

 During the middle of winter they are rare, and I have never found 

 them where young or brooding females were being fed. The season 

 of their greatest abundance is late in summer and in fall. 



Voice. — Most of the utterances of California shrikes have been 

 mentioned in earlier sections, but they may here be reviewed. The 

 spring song of the male consists of short trills or combinations of 

 clear notes repeated a number of times, yet varied in rhythm, pitch, 

 and quality. For example, each of the separate parts or units of 

 the song may be primarily a trill with three or four distinguishable 

 throbs in it. The quality of the trill often is described as liquid, but 

 the trill also contains harsher, burred qualities. Added to this trill 

 are clear, usually sharp, descending or ascending terminal notes. 

 Other songs lack a trill, two or three clear or burred notes, variously 

 accented and pitched, constituting the unit of song. Still other indi- 

 viduals precede a trill by clear notes. The most characteristic features 

 of the California shrike's song are not pitch or the structure of the 

 unit song of a series but rather the rhythmic repetition of song units 

 and certain general tonal qualities impossible of description or even 

 exact imitation. The units of song are repeated at an average of 

 one every two seconds, but the rhythm may be more rapid if the song 

 unit is especially short. 



The feeding territory song of gamheli given late in summer by males 

 and females alike is of the same general construction as the spring 

 song but appears to contain fewer high clear notes and more notes 

 rough in quality and resembling the quality of the harsh screeches or 

 begging notes. 



Immature birds give a decidedly different song of a continuous sort, 

 consisting of short screeches, gurgles, trills, and clear notes in a succes- 

 sion quite pleasing to the human ear. It is the continuous type of 



