﻿10 BULLETIN 1355, U. S. DEPAHTMENT OE AGEICULTURE 



be mentioned white mulberries, found in 3 stomachs; wild cherries^ 

 in 1; currants (probably wild), 1; blackberries, 9; elderberries, 10; 

 blueberries, 1; and grapes (the wild chicken grape), in 2. Berries 

 without even" so much economic importance, that appear most often 

 in the stomachs are those of spice bush, found 7 times; cornel of 

 various species, 22 times; bay, 5; Virginia creeper, 11; and sassafras, 

 6 times. Thus the predominance in the food of the nonuseful fruits 

 over the useful is great. The total vegetable matter, which also 

 includes a few grass seeds and flower and leaf buds, amounts to ap- 

 proximately one-seventh (14.72 per cent) of the yearly food, and is 

 second of the items in quantity. 



SUMMARY 



During the months April to October, inclusive, the food of the red- 

 eyed vireo is made up of six-sevenths animal matter, practically all 

 insects, and one-seventh vegetable, mostly fleshy fruits and berries. 

 Not more than 5 per cent of the entire food can be considered of great 

 economic value, while most of the remaining 95 per cent is of kinds 

 decidedly injurious to man's best interests. It is, therefore, obvious 

 that in usefulness the red-eyed vireo ranks high. 



PHILADELPHIA VIREC^ 



Vireosylva philadelphica 



The Philadelphia vireo is rather uncommon in the United States 

 over the greater part of its range, but may be found in considerable 

 abundance at times in Canada. Somewhat smaller and more gray 

 than the red-eyed vireo, it may be recognized by its small size and 

 the yellow of the throat and breast. The breeding range is in general 

 north of the United States, although there are records of breeding 

 birds as far south as Indiana. 



The collection of the Biological Survey contains 84 stomachs of 

 this bird; only 75, however, taken in the months of May, June, and 

 September, contained sufficient food for the proper estimation of per- 

 centages. (See fig. 3.) The food is largely animal in nature, there 

 being but 7.22 per cent not of this character. 



ANIMAL FOOD 



Insects make up all but 4.34 per cent of the animal food consumed 

 by the Philadelphia vireo in the summer months — this small per- 

 centage representing the spiders so frequently present in the food 

 of insectivorous birds. 



Lepidoptera. — The largest single item is the group consisting of 

 caterpillars and adult moths and butterflies, which together make an 

 average yearly percentage of 26.3, or more than a fourth of all the food 

 consumed. Of this, only 2.17 per cent refers to adults, leaving a total 

 of 24.13 per cent for the caterpillars. It appears that as the season 

 advances caterpillars become more and more important in the food, 

 for in May the percentage is only 15, while by September it has risen 

 as high as 39.94, which, taken with 5.59 per cent of adults, makes a 

 total of 45.53 per cent, or nearly half the entire food of the month. 



Coleo'ptei-'a. — A total for the year almost as great as that of cater- 

 pillars and their adult forms is found to be made up of beetles and 



