EASTERN BROWN-HEADED COWBIRD 443 



of insects and spiders, a few snails forming the exceptions. The insects comprise 

 wasps and ants (Hymenoptera), bugs (Hemiptera), a few flies (Diptera), beetles 

 (Coleoptera) , grasshoppers (Orthoptera), and caterpillars (Lepidoptera). * * * 

 Grasshoppers appear to be the cowbird's favorite animal food, and compose almost 

 half of the insect food, or 11 percent of the whole. * * * 



The vegetable food of the cowbird exceeds the animal food, both in quantity 

 and variety. When searching the ground about barnyards or roads the bird is 

 evidently looking for scattered seeds rather than insects, though the latter are 

 probably taken whenever found. Various other substances are also eaten, but 

 they are mostly of the same general character, such as hard seeds of grasses or 

 weeds, with but little indication of fruit pulp or other soft vegetable matter. 



In his list of vegetable matter the following items are the most prom- 

 inent: Corn was found in 56 stomachs, wheat in 20, oats in 102, and 

 buckwheat in one, as against seeds of ragweed in 176 stomachs, barn- 

 grass in 265 and panicgrass in 133. Grain as a whole amounted to 

 16.5 percent, or about one-sixth of the total food for the year, and 

 probably one-half of this was waste grain. "In summing up the results 

 of the investigation," he says, "the following points may be considered 

 as fairly established: (1) Twenty percent of the cowbird's food con- 

 sists of insects, which are either harmful or annoying. (2) Sixteen 

 percent is grain, the consumption of which may be considered a loss, 

 though it is practically certain that half of this is waste. (3) More than 

 50 percent consists of the seeds of noxious weeds, whose destruction is 

 a positive benefit to the farmer. (4) Fruit is practically not eaten." 



Dr. B. H. Warren (1890) says that cowbirds eat blackberries, 

 huckleberries, cedarberries, wild cherries, and summer grapes (Vitis 

 aestivalis). E. R. Kalmbach (1914) includes the cowbird among the 

 birds that eat the alfalfa weevil; from the first of May to the middle 

 of July, the weevil forms more than half of the bird's food. A. H. 

 Howell (1907) credits the bird with feeding on the cotton boll weevil. 

 And Hervey Brackbill sends me the following note: "One afternoon I 

 came upon a female cowbird eating dandelion seeds from a full-blown 

 seed-head. It must have found feeding from the upright stem incon- 

 venient, for after I had seen it take a few billfuls, it suddenly thrust 

 out one foot and pinned the stem to the ground and finished its eating 

 that way." 



Economic status. — It appears that in its food habits the cowbird 

 is decidedly more beneficial than harmful, doing very little damage to 

 the farmer's crops and destroying many destructive insects. The 

 chief cause of its unpopularity is the harm that it does through its 

 parasitic habits for it undoubtedly interferes with the successful 

 hatching and rearing of large numbers of small insectivorous birds. 



Paul Harrington, of Toronto, has sent me his notes on the study of 

 100 nests of various birds that contained cowbird eggs or young. 

 Most of these were nests of small birds, 48 of warblern, 37 of finches, 



