﻿FOOD HABITS OF THE VIEEOS 15 



to figure in the food only incidentally, but after the height of the 

 insect season has passed the birds turn to the ripe fruits as a source 

 of supply. Thus in April the vegetable matter formed but 0.12 

 per cent, but in August and September it ran as high as 18.69 and 

 9.33 per cent, respectively. Of the total food, this item makes up 

 5.76 per cent. 



SUMMARY 



The economic status of the warbling vireo is in some ways more 

 distinctly unfavorable than that of the other species of this family 

 of birds, especially in its consumption of ladybirds. In more than 

 a third of the stomachs examined the remains of these beneficial 

 beetles were found. Destruction of ladybirds is most evident in 

 stomachs collected in California, where the members of this group 

 of beetles are known to be unusually common. The species known 

 as the California ladybird leads the list in number, appearing in 41 

 stomachs, as high as eight to a single stomach in a few instances. 

 A second category of insects, which from predacious habits are to be 

 considered beneficial to man, is made up of the species of stink-bugs 

 of the genus Podisus, detected in 18 stomachs. Owing to their size, 

 a few will completely fill the stomach of the bird, and thus the 

 likelihood of extensive meals so far as numbers of the insects are 

 concerned is not great. 



On the other hand, the injurious insects taken by the warbling 

 vireo make up the greater part of the food. Lepidopterous remains, 

 including adult moths and butterflies, caterpillars, pupae, and eggs, 

 were taken from about 77 per cent of those examined. This alone 

 should atone for the bird's injurious proclivities along other lines. 

 In addition to lepidopterans, the consumption of scale insects, which 

 were found in 18 stomachs, and of bugs, omitting the forms of Podisus 

 and a few others, swells the total of injurious kinds consumed. 

 Little if any of the vegetable food taken was obviously cultivated, 

 in most cases being from plants not used for their fruits. It seems 

 reasonable, then, to class the bird as neither beneficial nor injurious. 



It is probable that a warbling vireo in a citrus grove would be 

 economically a liability, but in the woods and other places where the 

 conservation of coccinellids is not of so great importance there is little 

 to be considered objectionable in its habits. 



YELLOW-THROATED VIREO 



Lanivireo flavifrons 



The yellow-throated vireo is the handsomest of the family and 

 spends much of its time high up in the trees. This species is not 

 uncommon in the eastern part of the United States, where it remains 

 during the summer months to breed. It arrives in Florida and 

 Texas about the last of March and by the first week in May many 

 individuals have reached their breeding grounds. The return 

 migration in fall commences early in September, and by October 

 there are few birds of this species left in the United States. 



One hundred and sixty stomachs of the yellow-throated vireo, 

 collected during the months April to September, inclusive, were 

 available for analysis, the most noticeable fact established by the 



