THE FOOD HABITS OP NEBRASKA BIRDS. 225 



cannabalistic, and will devour one of its kind. Birds aggregate 

 thirty-four per cent of its food. Mice constitute twenty-six 

 per cent of the food and are most frequently eaten in March. 

 They are mostly meadow mice, while some are harvest mice, 

 white footed mice and house mice are also eaten. Carrion also 

 is sometimes eaten. 



The forty per cent of insect food is largely grasshoppers and 

 crickets, which are constantly taken and together form twenty- 

 four per cent of the food, and over half of that eaten in October 

 and November. Beetles form five per cent, and over half of 

 them (four per cent) are useful predaceons beetles, the remain- 

 der (one per cent) tiger beetles and tenebrionids. Caterpillars 

 form eight per cent of the food of January and February, and 

 six per cent of the entire food, and includes both cutworms and 

 the bristly kinds. Ants, wasps and flies (two per cent) consti- 

 tute the remaining insect food. Spiders form three per cent of 

 the food. 



The summary, then, of one-fourth mice, one-fourth grasshop- 

 pers, one- fourth other injurious insects and English Sparrows, 

 while the last one-fourth only is of beneficial wild birds and in- 

 sects, shows that the Northern Shrike does decidedly more 

 good than harm. 



Considering now our summering species. Here vertebrate 

 food comprises only twenty -eight per cent, and of this fifteen 

 per cent is small mammals, mostly mice and especially the 

 white-footed mice, taken mostly in winter when it forms one-half 

 of the food. Birds amount to only eight per cent and include 

 the Tree Sparrow, Grasshopper Sparrow, Song Sparrow, Chip- 

 ping Sparrow, White-throated Sparrow, Chimney Swift, Bell 

 Vireo, Snow-flake, Blue-gray Gnatcatcher and, as a relief, the 

 English Sparrow. The other four per cent of vertebrate food 

 are snakes, lizards, frogs and fish. Like the Northern Shrike 

 the southern species will occasionally eat carrion. 



But it is in their insect diet (seventy-two per cent) that the 

 smaller shrikes do most good. Orthoptera (thirty-nine per cent), 

 mostly grasshoppers, are very extensively consumed, and when 

 these insects are abundant the birds are left alone. They in- 

 clude the Red-legged Locust, the Dusty Road Grasshopper and 



