264 REPORT OF THE FOREST, FISH AND GAME COMMISSION. 



and caterpillars. In the case of one species of vireo, the bugs amount to nearly 

 forty-five per cent of the food of the year, and in some months rise to over seventy- 

 five per cent. The families represented are the soldier bugs (Pentatomidae), the 

 buffalo tree-hoppers (Membracidae), the jumping plant-lice (Psyllidae), the spittle 

 insects (Cercopidae), the leaf-hoppers (Jassidae) and scales (Coccidae). All of 

 these insects are to a greater or less extent inhabitants of trees, upon the foliage 

 of which they subsist. Some species of the spittle insects are very harmful to 

 pines, while the scales in some of their numerous species infest nearly every form 

 of tree or shrub. 



The next most important element of the vireo's food is made up of caterpillars, 

 with a few of the adult insects (moths). The harm that these creatures do to the 

 foliage of trees has been discussed so often as to require no further comment. 

 The remainder of the food is made up of small beetles, including some weevils, 

 many ants, a few grasshoppers and some other insects. 



The following observation illustrates how much good work a pair of these 

 birds may do in the way of insect destruction while rearing a brood of their off- 

 spring. A nestful of young, four in number, of the red-eyed vireo was kept 

 under observation from the time that the birds were first hatched until they 

 were able to leave the nest. They were watched for several hours each day in 

 hour periods, which were selected to fall in different parts of the day, so that 

 every hour was represented from early dawn until darkness closed the work. The 

 result was that the young were found to be fed by the parents on an average of 

 somewhat more than twelve times in each hour of daylight, from the time of hatch- 

 ing till they were able to fly. As there were at that time fully fourteen hours of 

 daylight in each day the birds were fed 168 times a day at least; or, as there 

 were four of them, forty-two times each. This means the destruction of 168 

 insects every day, and probably several times that number. 



Besides the various species of birds which have been discussed in the fore- 

 going pages, there are many others that incidentally do a good work in forest 

 preservation by the destruction of its insect enemies. As the tree-destroying 

 beetles migrate from tree to tree, which they sometimes do in swarms, they are 

 preyed upon by the various species of fly-catchers, swallows and other birds that 

 habitually take more or less of their food upon the wing. To illustrate: the 

 destructive engraver beetle Tomicus pini has been identified in the stomachs of 

 the following birds: Contopus virens, Hirundo erythrogaster, Petrochelidon hinifrons, 

 Iridoprocne bicolor, and Chordeiles virginianus. 



With the exception of the first, none of these is in any sense a forest bird, and 

 the insect must have been taken on the wine: as it was migrating- to new fields 



