﻿BULLETIN 1355, U. S. DEPARTMENT OF AGRICULTURE 



the Hutton vireos obtain nearly half their food from this source. 

 Stink-bugs form about a fifth of the food of both the blue-headed and 

 the Hutton vireos. The red-eyed and Philadelphia vireos each 

 make nearly a seventh part of their food of wasps and other hymenop- 

 terous insects, whereas the other vireos take barely half as much of 

 this kind of food. Beetles form about an eighth of the total food 

 of vireos, but in the case of the Philadelphia vireo they are a favored 

 article of diet and amount to nearly a fourth. The useful ladybird 

 beetles are notable in the diet of these birds and are especially im- 

 portant with the warbling and Hutton vireos, in each species amount- 

 ing to about a twelfth of the food. 



Most of the insects in the food of the vireos are either neutral or 

 definitely injurious in their economic relations and may be placed 

 on the credit side of the account of these birds. All vireos are 

 especially fond of caterpillars, creatures which are almost exclusively 

 injurious. Scale insects, which are uniformly destructive and num- 

 bered among the worst pests of horticulture, are a notable item of 

 vireo food; and other tree pests, as round-headed and flat-headed 

 borers, leaf beetles, click beetles, leaf hoppers, and tree hoppers are 

 freely eaten. Weevils, a group of beetles whose very name has 

 become almost a synonym for pest, also are preyed upon. Among 

 the species taken are such well-known destructive forms as the clover- 

 root, clover-leaf, cotton-boll, and nut weevils, the plum curculio, and 

 bark beetles. Vireos must be given credit also for destroying ants 

 and grasshoppers. 



Useful insects taken by the vireos include some of the hymenop- 

 terans, predacious bugs, and beetles, among which are ladybird 

 beetles (Coccinellidae). Vireos either find more ladybirds in the 

 ordinary course of their feeding habits than do most other. birds, 

 or specialize upon them, an unfortunate habit economically, as these 

 beetles are almost uniformly beneficial. Since vireos themselves 

 devour many of the pests attacked by ladybirds, however, and since 

 their capacity is so much greater, their depredations on ladybirds 

 must be excused on the principle that the greater pest destroyer is 

 more valuable than the lesser. 



Table 1. — -Percentages of various items in the food of vireos 



Species 



Num- 

 ber of 

 stom- 

 aehs 



Animal 

 food 



Vege- 

 table 

 food 



Scara- 

 baeidae 



Cocci- 

 nelli- 

 dae 



Chry- 

 some- 

 lidae 



Elate- 

 ridae, 

 Bup- 

 resti- 

 dae, 

 Ceram- 

 byei- 

 dae 



other 

 Cole- 

 optera 



Rhyn- 



choph- 



ora 



Black-wMskered vireo ( Vire- 

 osylva calidris) 



Red-eyed vireo ( Vireosylva 

 olivacea) 



Philadelphia vireo ( Vireo- 

 sylva philadelpfiica) 



Warbling vireos ( Vireosylva 

 gilva, subspp.) 



Yellow-throated vireo (Lani- 

 vireo tiavifrons) 



Blue-headed vireos (Lani- 

 vireo solitarius, subspp.) -- 



White-eyed vireos ( Vireo 

 griseus, subspp.) 



Hutton vireos ( Vireo huitoni, 

 subspp.) 



Bell vireos ( Vireo belli, sub- 

 spp.) 



569 



75 



340 



160 

 306 



221 

 70 



52 



87.50 



85.28 

 92.78 

 94.24 



98.26 

 96.32 



88.24 

 98.23 

 99.30 



12.50 



14.72 

 7.22 

 5.76 



1.74 

 3.68 



11.76 

 1.77 

 .70 



3.31 

 6.94 

 1.28 



1.84 

 1.67 



1.29 

 5.03 



8.74 



.62 



4.88 



1.36 

 8.12 

 2.19 



1.63 

 7.99 

 2.48 



.82 

 .96 



3.78 

 .25 

 3.98 



2.70 

 .96 

 1.03 



3.57 

 3.39 



2.31 



.85 

 1.69 



15.75 



.78 

 .47 

 .55 



1.82 

 .81 



1.46 

 1.01 

 1.31 



2.50 



1.13 

 3.43 

 1.45 



4.23 

 1.80 



S.21 

 2.75 

 6.09 



