﻿22 BULLETIN" 1355, U. S. DEPARTMENT OP AGRICULTURE 



ANIMAL FOOD 



Nearly nine-tenths of all the food eaten by the white-eyed vireos is 

 composed of insects, spiders, and other animal matter; of this all but 

 3.96 per cent is of insects. 



Lepidoptera. — Moths and butterflies and their larvae (caterpillars) 

 make up slightly less than one-third of the food of this species and 

 form the most important item of the diet. Of this portion, 20.66 

 per cent is represented by caterpillars, and except for February and 

 March a minunum of 18.7 per cent of the monthly food is of this 

 item. The maximum is reached in August with a percentage of 

 33.12. The adult insects, on the other hand, are not nearly so 

 plentiful in the stomachs, except during February and March, at 

 the time when the caterpillars have become scarce. Taking adults 

 and larvae together, the total does not fall below 26.33 per cent, 

 and rises to 37.93 in June. The yearly average for the adult forms 

 is 9,83 per cent, which with the caterpillars msikes a total percentage 

 of 30.49. 



Hemiptera. — As with other species of this family of birds, the 

 white-eyed vireos prey heavily upon stink-bugs (Pentatomidae) at 

 nearly all times, although the toll taken in February and March is 

 much greater than in summer. A second high point comes in Sep- 

 tember with 15.74 per cent. The yearly average is 8.56 per cent. 

 The rest of the bugs make up 11.71 per cent of the yearly food. 

 April is the time of maximum consumption, with a total of 24.18 

 per cent, and May follows with 19.25 per cent. Scale insects (Coc- 

 cidae), which have not figured in quantity in the economy of the 

 vireos previously discussed, are eaten by the white-eyes to the extent 

 of 2.85 per cent. This is not a high percentage, yet, considering the 

 small size of scales in general, it represents a great many individuals. 

 In April, 12.78 per cent of the total food, or more than half of all the 

 hemipterans eaten, was of the family Coccidae. 



Coteoptera. — Beetles of all kinds make up 12.78 per cent of the 

 total food. The leaf-eating forms ( Chrysomehdae) and weevils 

 (Rhynchophora) represent more than half of these, or 6.99 per cent. 

 Except for the Philadelphia and Bell vireos, no other of the vireo 

 family eats so many leaf beetles as this, while in percentage of 

 weevils consumed the white-eyed vireos are exceeded by three others^ 

 Ladybird beetles (Coccinelhdae), with a percentage of only 1.36, 

 seem not to be greatly in favor with the white-eyes. The wood-boring 

 beetles make up 2.31 per cent, the scarabs 0.66 per cent, and all other 

 beetles 1.46 per cent. 



Hymenoptera and Diptera. — Of the annual subsistence of the white- 

 eyed vireos 11.64 per cent is composed of wasps, bees, ichneumons, 

 and flies. The hymenopterans appear in the food in moderate quan- 

 tity each month, their greatest frequency being in May, at which 

 time they have a relative value of 11.16 per cent. On the other 

 hand, flies, though not found in stomachs collected after August, 

 are taken freely earlier in the year. In June 20.43 per cent of the 

 total food is made up of these insects, few of which are species of 

 economic importance. 



Orihoptera. — ^In discussing the food of the white-eyed vireos it 

 seems best to separate the grasshoppers from the miscellaneous in- 

 sects. The average percentage for the year is 5.36. In January 



