1 38 DA VET'S PRIMER 



THE CUCKOOS. 



Two species of cuckoos, the yellow-billed (see 

 photograph) and the black-billed, are common in the 

 United States east of the Plains, and a subspecies of the 

 yellow-billed extends westward to the Pacific. While 

 the two species are quite distinct, they do not differ 

 greatly in food habits, and their economic status is 

 practically the same. 



An examination of 155 stomachs has shown that 

 these cuckoos are much given to eating caterpillars, 

 and, unlike most birds, do not reject those covered with 

 hair. In fact, cuckoos eat so many hairy caterpillars 

 that the hairs pierce the inner lining of the stomach 

 and remain there, so that when the stomach is opened 

 and turned inside out, it appears to be lined with a 

 thin coating of fur. 



An examination of the stomachs of 46 black-billed 

 cuckoos, taken during the summer months, showed the 

 remains of 906 caterpillars, 44 beetles, 96 grasshoppers, 

 100 sawflies, 30 stink bugs, and 15 spiders. In all 

 probability more, individuals than these were repre- 

 sented, but their remains were too badly broken for 

 recognition. Most of the caterpillars were hairy, and 

 many of them belonged to a genus that lives in colonies 

 and feeds on the leaves of trees, including the apple. 



Of the yellow-billed cuckoo, 109 stomachs collected 

 from May to October, inclusive, were examined. The 

 contents consisted of 1,865 caterpillars, 93 beetles, 242 

 grasshoppers, 37 sawflies, 69 bugs, 6 flies, and 86 



