VIREOS. 



39 



scale. TTero, tlion, is an instance ^xhoro the bird eats the nsefnl beetle 

 and also its noxious prey. As there is nothing to indicate that the 

 bird exercises a choice between them, we must infer that it eats both 

 whenever it finds them. It eats the beetles and the food (scales) 

 upon M-hich they feed. From this point of view also it must be 

 allowed that the harm done by the vireos in eating coccinellids is offset 

 to some extent. 



WESTERN WAinUJXO VTRKO. 



(T//ro n'llniy: x/r (//)/. so///".) 



One hundred and ten stomachs of the warbling vireo have been 

 examined. They were collected during the seven months from April 

 to October, inclusive, and though hardly as many as could be desired, 

 they probably furnish a fair idea of the food during that portion of 

 the year. 



VegetaUe food. — Insects, with a few spiders, amount to over 97 

 percent of the diet, leaving less than 3 percent of vegetable matter, 

 practically all of which was taken in August and September; it 

 consisted of wild fruit (elderberries), a few seeds of poison oak, a few 

 other seeds, and some rubbish. 



Animal food. — Of the animal food the largest item is Lepidoptera ; 

 that is, caterpillars, moths, and the like. These amount to something 

 more than 43 percent of the whole. Caterpillars make up the great 

 bulk of this portion of the food and are a very constant and regular 

 article of diet. Fewer are eaten in July and August and more at the 

 beginning and end of the season. In April they amount to over 82 

 percent of the food of the month. Pupa? of codling moths were iden- 

 tified in four stomachs, and minute fragments probably of the same 

 were found in several others. A few adult moths also were found, 

 but the s])ecies could not be identified. 



Hemiptera are the next most important item of diet, and amount 

 to 21 percent. They consist of stink-bugs, leaf-bugs, leaf-hoppers, 

 spittle-insects, tree-hoppers, and scales. The last were the black olive 

 species {Saissetia olea^). Coccinellid beetles, or ladybirds, were eaten 

 to the extent of over 19 percent of the whole. None was in the 

 stomachs taken in October, while the greater part (over 03 percent) 

 was contained in those obtained in July. The species belong to the 

 genera Hippodamia and Coccinella, which are larger than those of 

 the ffenus Scvmnus selected by the warblers. Other beetles, mostly 

 harmful species, amount to more than 7 percent. 



Hymenoptera, which are an important food of the warblers, are 

 conspicuous by their absence in the stomach of the warbling vireo. A 

 little more than 1 percent represents the sum total. They consist of a 

 few ants and an occasional wasp. 



