FIELD tiPARKOW. 



79 



The laboratory iuvestigation includes 175 stomachs, collected during 

 every month of the year, from 15 States and the District of Columbia, 

 chiefly in New York, Massachusetts, and the District of Columbia in 

 the East, and Kansas and Wyoming in the West. Of the total food 

 they contained 41 percent was animal matter and 59 percent vegetable 

 matter. Of the animal material v/eevils form 2 percent; leaf -beetles, 

 2 percent; ground-, tiger-, click-, and May-beetles, collectively, 9 

 percent; caterpillars, 4 percent; grasshoppers, 6 percent; leaf-hoppers, 

 true bugs, sawflies, ants, flies, and spiders, taken together, 14 percent, 

 and parasitic wasps, 4 percent. This last item is the principal point 

 wherein the field sparrow diifers in food habits from the chipping 



Fig. 16.— Field sparrow. 



sparrow — a difference that is not to the advantage of the record of the 

 species from an economic standpoint, since, as has been shown, these 

 wasps are dangerous parasites of many caterpillars. Of the vegetable 

 food 51 percent consists of the seed of grasses, for the most part such 

 species as crab-grass and other panicums, pigeon-grass, broom sedge, 

 poverty grass [Aristida), and sheathed rush grass. Seeds of such 

 weeds as chickweed, lamb's-quarters, gromwell, amaranth, purslane, 

 spurge, wood sorrel, and knotweed amount to 4 x^ercent. The per- 

 centage of timothy is insignificant, but that of oats is comparatively 

 large, as they constitute 4 percent of the food. 



