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.
The Bullock oriole[38] is practically a counterpart of the Baltimore oriole, taking the place of that species west of the Plains and throughout the Pacific coast region. It does not essentially differ in its habits of nesting or in its food from its eastern relative, but it is less beautiful in plumage. The examination of 162 stomachs shows that 79 per cent of its food consists of insects, with a few spiders, a lizard, a mollusk shell, and eggshells. Beetles amounted to 35 per cent, and all except a few ladybugs were harmful species. Ants were found in 19 stomachs, and in one there was nothing else. Bees, wasps, etc., were in 56 stomachs, and entirely filled 2 of them. Including the ants, they amount to nearly 15 per cent of the food of the season.
[38] Icterus bullocki.