﻿EOOD HABITS OF THE VIREOS 9 



flowers, suffer most from the red-eye; but their number is so great 

 that it is probable that no one species is much affected by the vireo. 

 As only two instances were found of the eating of a honeybee by this 

 bird; it is evident that this vireo is not destructive to these useful 

 i"asects. As with most of the hemipterans, the greatest destruction 

 of the hymenopterans by the bird is in spring, the percentage for 

 April being 20.39. This figure is increased to 20.97 in May, and from 

 then on to the close of the season it diminishes steadily to 3.18 in 

 October. Hymenopterans, with 10.79 per cent, stand third in quan- 

 tity in the annual food of this species. 



Diptera. — Flies, although eaten more or less regularly, do not at 

 any time form a large portion of the diet of the red-eye. Remains of 

 these were found in 119 stomachs and amounted to 4.46 per cent of 

 the total food. Crane flies and midges appear to be the kinds usually 

 taken; this is undoubtedly because such forms are more abundant in 

 the natural feeding haunts of the bird. 



Other insects. — Grasshoppers, katydids, stone flies, tree crickets, and 

 similar insects together make up 4.59 per cent of the food. Of 569 

 stomachs examined, 88 contained at least traces of these forms, the 

 percentage steadily increasing toward fall. This increase may be 

 attributed to the greater abundance of the grasshoppers and katydids 

 at that season and als<s to the growing scarcity of the foods which 

 formed substantial percentages in spring. There are both beneficial 

 and injurious forms included in the miscellaneous category; but it is 

 evident from the stomach analyses that the injurious forms, as grass- 

 hoppers, outnumber the beneficial forms — dragonflies, and other pre- 

 dacious amphibious insects — -by more than two to one. One can 

 hardly begrudge the vireo this small toll (about 2 per cent) collected 

 while performing a good service. 



Spiders. — Most spiders make their homes on bushes and in the 

 branches of trees and there spread their filmy nets to catch whatever 

 unwary insect may stumble into them. Thus both the red-e3^e and 

 the spider are helping to check the increase of insects. But as the 

 predatory activity of 10 or even 100 spiders is not comparable to 

 that of one vireo, the bird is economically the more useful. That the 

 remains of spiders were detected in 188 of the stomachs examined 

 indicates that they are a favorite article of diet with this vireo. In 

 August, when they are most abundant, spiders amount to nearly 

 6.5 per cent of the total food, but this figure is not maintained either 

 in spring or fall, and the annual percentage is only 4.05. 



Other animal food. — Apparently it is only curiosity which leads a 

 red-eyed vireo to take animal food other than insects or spiders. 

 Remains of snails, probably of a kind usually found on leaves and 

 grass, were found in two stomachs collected in June, and as they form 

 onl}'- 0.02 per cent of the food of that month they are entirely lost in 

 the yearly averages. 



r VEGETABLE FOOD 



During the first part of the year, when insect food is plentiful, the 

 red-eyed v^ireo takes very little vegetable matter. From August on, 

 however, the vegetable food increases rapidly, until in October the 

 percentage of 49.41 is reached. Berries of all kinds find favor with 

 this bird, from the sweet mullxu-ry to the bitter barberry. Of the 

 berries most used by man and eaten also by the red-eyed vireo may 



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