50 FOOD HABITS OF THE GROSBEAKS. 



canelkis), which at times is very destructive, the plum leaf-beetle 

 (Nodonota tristis), which causes dropping of cotton bolls, a species 

 (Griburius equestris) which feeds on wild roses, and another wild- 

 flower beetle (Cryptocephalus quadrimaculatus) . 



With the Chrysomelidse is concluded also the list of principal 

 Coleopterous families. The grosbeak eats few others. One rose- 

 breast devoured 5 of the decidedly malodorous burying beetles 

 (Silpha noveboracensis) , which feed on carrion, while another cap- 

 tured one hard, polished Hister, an insect of similar habits. Sixteen 

 of the little orange and black Ips fasciatus were secured by one of 

 the three birds which fed upon this occasional depredator of stored 

 vegetables and grain. 



It thus appears that a large number of the beetle enemies of agri- 

 culture are preyed upon by the rose-breasted grosbeak. An almost 

 equal array of serious pests is secured from the ranks of another 

 order, which is eaten to only one-ninth the extent that beetles are, 

 namely, the moth and butterfly order or Lepicloptera. 



This group may be discussed conveniently under the heads " larvae " 

 and " adults." The latter do not seem to be eaten to any great extent 

 by birds, and only 2 rosebreasts fed upon them. Four moths were 

 secured, but they composed less than 0.2 percent of the total food. 

 The larvae or caterpillars, however, are more generally relished by- 

 birds and often are eaten in large numbers. Twenty-two out of the 

 176 rosebreasts had eaten caterpillars, some of them securing from 6 

 to 14 each, which usually constituted from 50 to 85 percent of the 

 stomach contents. They make up 3.82 percent of the entire food of 

 all the rosebreasts examined. 



It is well known that at times the depredations of lepidopterous 

 insects, such as canker worms, tent caterpillars, gipsy moths, and 

 many others, are very serious, threatening ruin to orchards and even 

 large forests, and thus becoming of State, if not National, importance. 

 The difficulties encountered in combating such pests render the aid 

 of natural enemies most valuable. It should be widely known that 

 the rose-breasted grosbeak is conspicuous among the enemies of these 

 insects, and also that it feeds upon no fewer than eight of the very 

 worst lepidopterous pests. 



Among the more widely known of these are the canker worms, 

 which are very destructive to both orchards and woodlands. They 

 often strip orchards so that they appear as if fire swept, and when 

 their attacks are continued for a few years the trees die. The rose- 

 breasted grosbeak devours both the spring canker worm (Paleacrita 

 vernata, fig. 35) and the fall canker worm (Alsophila pometaria, 

 fig. 27). Two birds collected in Illinois in May had fed upon the 

 former caterpillar, while O. W. Knight testifies that in Pleasant 

 Valley, Me., the birds actively attack the other. 



