828 EXPERIMENT STATION EECOED. 



ZOOLOGY. 



The food of the bobolinks, blackbirds, aiid grackles, F. E. L. 

 Beal ( U. /S. Dept. Aijr. , Dirision of Jjlologlcal Survey Bui. 13, pjj. 

 77^ figs. 6). — In this l)ulletiii the author discusses the food habits of 

 the bobolink, cowbird, yellow-headed l)lackbird, red-winged blackbird, 

 California red-winged blackbird, rusty blackbird, Brewer's blackbird, 

 crow blackbird, and boat-tailed grackle. 



It is stated that a study of the stomach contents of blackbirds con- 

 firms to some extent the popular estimate of their grain-eating habits, 

 but shows also that these birds destroy large quantities of seeds of 

 noxious weeds and a great number of insects. In general, it was 

 found that the vegetable portion of the food exceeded the animal por- 

 tion and that the latter consisted mainly of insects. The vegetaljle 

 food comprised for the most part grain, grass, and weed seeds. The 

 author states that the animal food of the 9 species of blackbirds 

 must be considered for the most part in their favor, as the insects 

 eaten are injurious. 



Of bobolinks, 291 stomachs were examined, coming from 19 States 

 and taken during 5 months from May to September. The food con- 

 sisted of 57.1 per cent animal and 42.9 per cent vegetable matter. 

 Most of the stomachs were collected in Northern States, but the author 

 believes that the great damage done by bobolinks to the rice crops is 

 due to the immense numbers of bobolinks and the fact that the rice 

 iields lie in the direct course of their spring and fall migrations. It is 

 concluded that the harm done b}' the bobolink far outweighs its behetits. 



Of the cowbird, 544 stomachs were examined from 20 States, taken 

 during every month of the year. The animal matter contained in 

 these stomachs was 22.3 per cent, while the vegetable matter vvas TT.7 

 per cent. Corn, wheat, oats, and buckwheat were found in the stom- 

 achs, grain as a whole amounting to 1(3.5 per cent of the food of the 

 year. Weed seeds amounted to 60 per cent of the whole food. The 

 author summarizes the results of the investigation of this bird as fol- 

 lows: Twenty per cent of the cowl)ird's food consists of noxious 

 insects; 10 per cent of grain, about half of which is waste grain; while 

 more than 50 per cent consists of noxious weed seeds. 



Of the yellow- headed blackbird, 138 stomachs were received from 

 10 States during 7 months. The food consisted of 33.7 percent animal 

 and 66.3 per cent vegetable matter. Grain, collectively, amounted to 

 38.9 per cent of the total food. While a considerable portion of this 

 grain was undoubtedly waste, the bird may evidently do great damage 

 to grain fields. The author concludes that this species feeds princi- 

 pally upon insects, grain, and weed seeds, that in general it does much 

 good l)v destroying noxious insects and troublesome weeds, but that 

 where grain is very abundant it may b(; injurious to such crops. 



Of the red-winged blackbird, l,u;3«8 stomachs were collected from 80 



