BIRDS AS CONSERVATORS OF THE FOREST. 257 



insignificant, collectively a scourge, which prey upon the hopes of the fruitgrower, 

 and which, if undisturbed, would bring his care to naught."* 



The food of the warbler, with the exception of the few ground-feeding species, 

 consists of such insects as are found upon the trunks, branches, leaves and flowers 

 of trees, mostly those of the forest, though many species of these birds visit the 

 orchard for food, and sometimes nest there. As might be expected, small beetles, 

 ants, and caterpillars, with some scales and plant-lice, make up the bulk of the 

 food of the tree-feeding species. The three elements which appear most prominently 

 in the stomachs are beetles, ants and caterpillars. These are remarkably constant 

 elements of the food, and are found in most of the stomachs examined. The 

 beetles are largely of the family of snout-beetles (Rhyncophora), all of which are 

 injurious to some plant, and many of them to forest trees. To show the capacity 

 of some of these small birds, the contents of several of their stomachs may be 

 cited. No. 1 contained 68 weevils, some scales, a pupa case and a spider. 

 No. 2 contained 65 weevils, with a few other insects. No. 3 had at least 53 

 weevils, with fragments of others, and some other insect. No. 4 contained 

 50 weevils, with remains of others, a leafhopper and some ants. No. 5 was filled 

 with 35 weevils, remains of Hymenoptera (wasps), caterpillars, a pupa case and 

 a spider. These five birds had eaten altogether 271 of these injurious weevils, 

 and from the broken remains contained in their stomachs it is highly probable that 

 300 is much nearer the true figures. In another stomach were found 52 specimens 

 of another beetle, with remains of other insects. 



While the different species of the warbler family show some peculiarities in 

 the selection of their food, there is still a pronounced similarity in the elements 

 selected by all those whose haunts are the same. The species that live upon 

 trees, which constitute a majority of the family, not only show the same tastes 

 in diet, but also strongly resemble in this respect the birds of other families that 

 live and obtain their food in the same places. Thus the food of the warblers is 

 strongly suggestive of that of the titmice, the nuthatches, the creepers and the 

 kinglets. 



A single instance may serve to illustrate the kind of work done by this family 

 of birds. The spring of 1900 was remarkably cold and backward in the Northeastern 

 States, and a multitude of birds had migrated as far north as Massachusetts, but 

 were held from going farther by the cold and snow which still lay upon the ground 

 in New Hampshire and northward. In the meantime, owing to the cold northerly 

 winds, the insects were slow to come from their hiding-places, so that the birds 



' Birds of the Colorado Valley, p. 201. 

 17 



