﻿FOOD HABITS OF THE VIREOS 



ANIMAL FOOD 



Practically six-sevenths of the food consumed by the red-eye is 

 of animal origin, and very nearly all of it is insects. The remainder 

 is composed of the small snails that are found more or less fre- 

 quently on leaves and grass. 



Lepidoptera. — Caterpillars form by far the largest single item in 

 the yearly sustenance, and amount to 32.43 per cent of the total, or 

 more than one-third of the animal matter eaten. They were found 

 in 371 of the stomachs, over half of the number examined. In 

 general it is difficult or even impossible to identify «the species of 

 caterpillars found in stomachs, but the larvae of sphinx moths, 

 swallowtail butterflies, tent caterpillars, and codling moths were 

 detected. Most caterpillars are injurious to man's interests or have 

 characteristics which at any time may cause them to become so. 

 Hence, so great a destruction of these larvae as the figures show is a 

 strong argument in favor of this vireo. 



Lepidopterous forms other than caterpillars make up a small 

 percentage (2.76) of the annual food. Adult moths and butterflies 

 were found in 26 stomachs, pupae (cocoons and chrysalids) in 14, 

 and eggs in 3. These may all be placed with caterpillars as injurious 

 forms. 



Coleoptera. — Beetles majvc up 10.84 per cent of the total food for 

 the year, 1.29 per cent of which is composed of lady beetles. Lady 

 beetles, or "ladybirds," as the members of the family Coccinellidae 

 are often called, are, with a very few exceptions, decidedly beneficial 

 to man's interests. Eighty-five of the stomachs examined contained 

 coccinellids, some from three to eight individuals each. It can only 

 be said that, considered in connection with all the food taken, the 

 destruction of lady beetles is more than repaid by beneficial activities 

 in other directions. 



Scarabaeid beetles, otherwise known as ''leaf chafers" and ''dung 

 beetles," form a small item in the yearly food of this bird. During 

 June, when the larger leaf-infesting species are in greatest abundance, 

 the percentage of this item rose to 11.88. Among the forms recog- 

 nized are many species of the medium-sized and robust brown leaf 

 chafers, which are capable of considerable damage. Scarabaeids 

 were found in 75 of the 569 stomachs examined and made a total of 

 3.31 per cent of the food. 



Leaf beetles (Chrysomelidae) are inji^rious in their feeding habits; 

 hence the quantity taken by the vireo is to be considered a gain to 

 man. Though a species of leaf beetle may be known to attack 

 only wild plants, there is always the possibility that it may adapt 

 itself at any time to life among the cultivated plants, shrubs, or trees, 

 and with that adaptation become detrimental to man's interests. 

 Examination of the stomachs shows that the percentage of leaf 

 beetles rises to 4.4 in May, after which it becomes less, disappearing 

 entirely in October. In fact, the percentages vary directly with the 

 abundance of the item, as is to be expected. Considered as part of 

 the annual diet, chrysomclids make up 1.63 per cent and were found 

 in 136 of the stomachs examined. 



Representatives of the three families Ccrambycidae, Buprestidae, 

 and Elateridae have been grouped for convenience. The larvae, or 

 grubs, of all these beetles pass their lives either within wood or among 

 the roots of })hints anfl are very destructive to lurn})er and grain 



