Stomachs of nestlings, varying in age from 24 hours to some that were nearly fledged, were found to contain 89 per cent animal to 11 per cent vegetable matter. The largest items in the former were caterpillars, grasshoppers, and spiders. In the latter the largest items were fruit, probably cherries; grain, mostly oats; and rubbish.
[BALTIMORE ORIOLE.]
Fig. 12.—Baltimore oriole. Length, about 7½ inches.
Brilliancy of plumage, sweetness of song, and food habits to which no exception can be taken are some of the striking characteristics of the Baltimore oriole[37] ([fig. 12]). In summer it is found throughout the northern half of the United States east of the Great Plains. Its nest commands hardly less admiration than the beauty of its plumage or the excellence of its song. Hanging from the tip of the outermost bough of a stately elm, it is almost inaccessible to depredators and so strongly fastened as to bid defiance to the elements.
[37] Icterus galbula.
Observation both in the field and laboratory shows that caterpillars constitute the largest item of the fare of the oriole. In 204 stomachs they formed 34 per cent of the food, and they are eaten in varying quantities during all the months in which the bird remains in this country. The fewest are eaten in July, when a little fruit also is taken. The other insects consist of beetles, bugs, ants, wasps, grasshoppers, and some spiders. The beetles are principally click beetles, the larvæ of which are among the most destructive insects known; and the bugs include plant and bark lice, both very harmful, but so small and obscure as to be passed over unnoticed by most birds. Ants are eaten mostly in spring, grasshoppers in July and August, and wasps and spiders with considerable regularity throughout the season.
During the stay of the oriole in the United States, vegetable matter amounts to only a little more than 16 per cent of its food, so that the possibility of its doing much damage to crops is very limited. The bird is accused of eating peas to a considerable extent, but remains of such were found in only two cases. One writer says that it damages grapes, but none were found in the stomachs.