THE BOBOLINK. 



19 



In view of the fact that the food habits of the bird during migration 

 are well known, attention has been directed chiefly in the present 

 laboratory investigation to the character of the food taken on the 

 breeding grounds. Of 291 stomachs examined (see p. 72), 231 were 

 -obtained from various points in the North, embracing nineteen States, 

 from Massachusetts to Montana, the District of Columbia, and Onta- 

 rio. They were taken in the five months from May to September, 

 inclusive, but the majority of the September birds whose stomachs 

 have been examined may be regarded as belated migrants. The food 

 for these five months was found to consist of 57.1 percent animal mat- 

 ter and 42. 9 percent vegetable. This result would be rather surprising 

 but for the fact that only two of the May and nine of the September 

 stomachs were collected in the rice fields. The general character of 

 the food during the five months is shown in the accompanying diagram 

 (fig. 2). 



Fig. 2.— Diagram showing proportions of animal and vegetable food of bobolink in each month from 

 May to September inclusive. (The figures in the margins indicate percentages.) 



Of the insect food, as determined by the examination, beetles con- 

 stitute nearly 19 per cent. Predaceous species (Carabidse), which are, 

 broadly considered, useful insects, are represented only by a trace; 

 snout-beetles, or weevils (Rhynchophora), amount to 8.9 percent, and 

 in May to 20.8 percent; and other beetles, of various families, and all 



