CALIFORNIA SHRIKE 165 



seems to be indicated by the fate of three nests I have observed near 

 Pinole. The young in these nests were allowed to fall to the ground 

 or the nests became dangerously tilted as a result of placement among 

 small branches a centimeter or less in diameter. 



The female builds the nest with little or no active aid of the male. 

 The difficulty of distinguishing male and female in the field makes 

 it hard to be sure that this is always true. To judge from the actions 

 of pairs in which the sexes of the birds were known, the male usually 

 follows the female while she is gathering material, and he may go 

 with her to the nest but, in my experience, has not been seen to touch 

 the nest or to bring material to the female (see however, Johnson, 1938, 

 with respect to Lanius ludovlclanus migrans). He may sit within a 

 foot of the female while she is building. California shrikes are 

 extremely shy while engaged in nest construction and will cease 

 activity when the nest is approached within 60 yards. It is difficult, 

 therefore, to observe the manipulation of material at the site, which 

 is usually well hidden from view. Foraging for material is con- 

 ducted, for the most part, within a radius of 50 yards of the nest. 

 The greatest distance that I have observed a bird transport substances 

 designed for the nest is 100 yards. Nevertheless, on occasion it is 

 fairly certain that materials are obtained at even greater distances 

 from the nest. One female was seen to go to an old Bullock's oriole's 

 nest constructed of hair and tug vigorously at the edge, finally secur- 

 ing small pieces of the rim which it carried directly to its own nest. 



Eggs. — With gamheVi., in the vicinity of San Francisco Bay, sets of 

 seven eggs are as common as those of five, six being the usual number. 

 In San Diego County, Calif., on the other hand, Bancroft states that 

 ganibeli lays five or six eggs, usually five. Likewise, I have taken 

 immerous complete sets of five eggs in western Los Angeles County. 



The time of laying of first sets ranges from April and early in May 

 in the north to late in March and early in Aj^ril in the San Diegan 

 district of California. Occasionally sets of eggs are found in Febru- 

 ary in southern California. Second broods and replacement of 

 destroyed nests may prolong the laying period into the early part of 

 July. 



Eggs of the loggerhead shrike vary from dull white to either light 

 neutral gray or buff in ground color. The spots are usually small, 

 the maximum diameter in most eggs being about 21/^ millimeters, but 

 occasionally spots and splotches as large as 6i/^ millimeters occur. 

 The sharply defined surface markings vary from neutral gray to vari- 

 ous tones of yellowish brown and umber. There also are indistinct 

 light gray spots deposited in layers beneath the surface of the eggshell. 

 Occasionally, fine black scrawlings appear near the large end of the 

 eggs. Spots are more concentrated at the large end but rarely are 

 grouped into pronounced blotches with intervening unpigmented 



