26 FOOD OF BOBOLINK, BLACKBIRDS, AND GRACKLES. 



Beetles form 5.3 percent of the year's food. The predaceous ones, 

 or those that prey to a greater or less extent on other insects (Cara- 

 bidge and a few Cicindelidse), although living on the ground and 

 often found by cowbirds, are rarely eaten, the aggregate for the year 

 being about three-fourths of one percent of the whole food. Of the 

 eight families of beetles represented in the food, only one group, the 

 snout-beetles or weevils (Rhynchophora), are eaten to any noticeable 

 extent, and these amount to little more than 2 percent of the food of 

 the year, although in June they rise to more than 9 percent. They 

 belong mostly to the families of scarred snout-beetles (Otiorhynchidse), 

 curculios (Curculionidffi), and 'bill bugs' (Calandridse), and as the}!" 

 are all potentially harmful and most of them actual pests, their 

 destruction is a benefit to agriculture. The rest of the beetle food, 

 ^comprising species that are all more or less injurious, amounts to a 

 little more than 2 percent, and is taken chiefly in April, May, and 

 June. 



Grasshoppers appear to be the cowbirds' favorite animal food, and 

 compose almost half of the insect food, or 11 percent of the whole. 

 They are -first taken in ]\Iarch, when the birds return from their winter 

 home, reach a maximum of 45.1 percent in August, and decrease to 

 6.2 percent in November. This is a large record, compared with 

 those of most other birds whose food has been accurately determined. 

 It is much greater than those of the crow, crow blackbird, or red- 

 winged blackbird, all noted ground feeders, and is exceeded only by 

 those of the mcadowlark and a few of other families. 



Caterpillars are eaten to some extent in everj^ month of the cow- 

 birds' sta}' in the North, but do not constitute a very important element 

 of the food, averaging only a little more than 2 percent of the whole. 

 The greatest number, amounting to a little more than 10 percent, are 

 eaten in May. The notorious army worm {Leucania umjfunctd) was 

 identified in four stomachs, and was probably contained in many more, 

 but not in a condition to be recognized. One small moth and one 

 ephemerid were also found. 



Spiders were found in manj' stomachs, but not in large numbers. 

 Thc}'^ seem to be eaten wherever they are found, l)ut prol)abh' only ter- 

 restrial species are taken. Snails were found in a number of stomachs. 



Eggshells occurred in several stomachs, but in such small quantities 

 as to preclude the probaljility that they were taken from the nests of 

 other birds. "When young birds are hatched the parents remove the 

 eggshells and drop them at some distance from the nest, where, 

 doubtless, they are found and eaten by other birds, for bits of eggshell 

 appear more or less frequently in the stomachs of nearly cverv species 

 examined. 



The vegetable food of the cowbird exceeds the animal food, l)oth 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 arc probably taken whenever found. Various 



