392 SHRIKES 



621. Lanius borealis Vieill. NORTHERN SHRIKE. 



Adults in summer. Wide streak on side of head, and wings and tail 

 black, wings and tail extensively marked with white ; under parts white, 

 barred or undulated with grayish; upper parts pale ash gray becoming 

 whitish on forehead, superciliary, and rump; lores black and grayish, 

 a whitish spot on lower eyelid. Adults in winter : similar, but basal half 

 of lower mandible light brownish horn color, grayish in life, and lores 



From Biological Survey, U. S. Dept. of Agriculture. 

 Fig. 483. 



chiefly light grayish or whitish. Young : largely washed with brownish. 

 Length: 9.25-10.75, wing 4.35-4.60, tail 4.50-4.70, bill from nostril .50-.55. 



Distribution. Breeds from Labrador, Hudson Bay, and Cook Inlet, 

 Alaska, northward ; migrates south in winter as far as Virginia, Kansas, 

 Arizona, and northern California. 



Nest. In bushes or thorny trees, a rude, bulky structure of twigs, 

 grasses, and stems, lined with mosses, lichens, and feathers. Eggs : 4 to 

 6, pale bluish green, spotted with brown and purple. 



Food. In winter, mice, English sparrows, grasshoppers, and other 

 birds and insects. 



The northern shrikes reach Colorado in October, Prof. Cooke 

 says, first appearing on the mountains above timberline. Some of 

 them winter as high as 9500 feet in the mountain parks, but most 

 of them work their way down to the plains, where they find abun- 

 dant food in the shape of horned larks. In other regions they are 

 often tempted to visit cities by the unfailing supply of English 

 sparrows, for in habits they are miniature birds of prey. 



622a. Lanius ludovicianus excubitorides Swains. WHITE- 



RUMPED SHRIKE. 



Adults. Bill, lores, and nasal tufts wholly black ; upper parts light slate 



gray ; upper tail coverts whitish ; 

 under parts pure white, very lightly, 

 if at all, marked. Young : like adults, 

 but base of lower mandible light- 

 Fig. 484. colored, general colors less strongly 



