﻿FOOD HABITS OP THE VIREOS 27 



Other insects and spiders. — The rest of the animal food of the Bell 

 vireos is composed of a few miscellaneous insects and spiders and a 

 very few snails, spiders (2.71 per cent) being the most important. 

 The first appearance of this group of food items was in the stomachs 

 of birds taken in June, at which time it composed 6.93 per cent of 

 the food. An immediate drop to 2.52 per cent took place the next 

 month, and the percentage in August was nearly the same. 



VEGETABLE FOOD 



It is not until July that the Bell vireos feed on wild fruits. At 

 that time 1.57 per cent of the subsistence is of vegetable matter. 

 In August the percentage decreased slightly to 1.25. The average 

 percentage for the year is only 0.7. 



SUMMARY 



During the summer months the Bell vireos consume a great many 

 injurious insects and very few beneficial ones. Grasshoppers, 

 locusts, caterpillars, and moths are frequently injurious to man's 

 best interests, as also are many of the hemipterans. The percentage 

 of these insects in the food of birds of this species is 73.58, nearly 

 three-fourths of the total. Of the remainder about half the beetles 

 and^ hymenopterans are injurious. This will add about 11 per cent, 

 leaving about 16 per cent of the food of debatable import. As the 

 small quantity of vegetable matter eaten is of no economic significance 

 it may be disregarded. Ladybird beetles are about the only oeneficial 

 forms that the birds take, and these are not consumed in very great 

 numbers. 



GRAY VIREO 



Vireo vicinior 



The gray vireo is a rare bird in a restricted range, and for this 

 reason is of very little economic importance. It may be seen in 

 southern California, southern Nevada, Arizona, New Mexico, as far 

 east as western Texas, and south to northern Mexico and on the 

 peninsula of Lower California. 



There are only two stomachs in the collection of the Biological 

 Survey, and, while from such limited material it is impossible to draw 

 more than an inference, it may be said that the habits indicated are 

 similar to those of the Hutton and Bell vireos. Caterpillars and a 

 small moth were found in one stomach, together with a stink-bug 

 (Prionosoma jyodoyioides) , a tree hopper (Platycentrus acuticornis) , 

 and a tree cncket (Oecanthus). In the other stomach two dobson 

 flies (Chauliodes) , a small cicada (Tihicinoides hesperius), and a 

 long-homed grasshopper made up the greater part of the contents; 

 two beetles (Acmaeodera neglecta and PacJiyhrachys) complete the 

 list. 



Because of the relative infrequency of its occurrence and the 

 chiefly beneficial nature of its food habits as here indicated, it is 

 probable that the gray vireo will never prove destructive. 



