2 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 
Black-whiskered vireo ( Vire- 
osylva calidris) 
Red-eyed vireo ( Vireosylva 
olivacea) _ . 
Philadelphia vireo ( Vireo- 
sylva philadelphicu) 
Warbling vireos ( Vireosylva 
gilva, subspp.) .. 
Yellow-throated vireo (Lani- 
vireo liavifrons) 
Blue-headed vireos (Lani- 
vireo solitarius, subspp.).... 
White-eyed vireos ( Vireo 
griseus, subspp.) 
Hutton vireos ( Vireo huttoni, 
subspp.) 
Bell vireos ( Vireo belli, sub- 
spp.) 
Num- 
ber of 
stom- 
achs 
75 
340 
160 
306 
221 
70 
52 
Animal 
food 
87.50 
85.28 
92.78 
94.24 
98.26 
96.32 
88.24 
98.23 
99.30 
Vege- 
table 
food 
Scara- 
baeidae 
12. 50 L 
14. 72 I 
7.22 I 
5.76 
1.74 
3.68 I 
11. 76 I 
1.77 j 
.70 L 
3.31 
6.94 
1.28 
1.84 
1.67 
.66 
.27 
Cocci- 
nelli- 
dae 
1.29 
5.03 
8.74 
.62 
4.88 
1.36 
8.12 
2.19 
Chry- 
some- 
lidae 
1.63 
7.99 
2.48 
.82 
.96 
3.78 
.25 
3.98 
Elate- 
ridae, 
Bup- 
resti- 
dae, 
Ceram- 
byci- 
dae 
2.70 
.96 
1.03 
3.57 
3.39 
2.31 
.85 
1.69 
Other 
Cole- 
optera 
15.75 
.78 
.47 
.55 
1.82 
.81 
1.46 
1.01 
1.31 
Rhyn- 
choph- 
ora 
2.50 
1.13 
3.43 
1.45 
4.23 
1.80 
3.21 
2.75 
