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_.
One of the most interesting articles of food in the oriole's dietary was
the black olive scale, found in 45 stomachs, and amounting to 5 per cent
of the food. In several cases these scales formed 80 per cent or more of
the contents, and in one, 30 individual scales could be counted. They
were evidently a standard article of diet, and were eaten regularly in
every month of the oriole's stay except April. Hemipterous insects other
than scales, eaten quite regularly, make up a little more than 5 per cent
of the food. They were mostly stinkbugs, leaf hoppers, and tree hoppers.
Plant lice were found in one stomach.
Moths, pupæ, and caterpillars compose the largest item of the oriole's
animal food; the average consumption during its summer stay Is a little
more than 41 per cent. Of these, perhaps the most interesting were the
pupæ and larvæ of the codling moth. These were found in 23 stomachs,
showing that they are not an unusual article of diet. No less than 14 of
the pupal cases were found in one stomach, and as they are very fragile
many others may have been present, but broken beyond recognition.
Grasshoppers probably do not come much in the oriole's way. They were
eaten, however; to the extent of a little more than 3 per cent. But in
spite of the fact that grasshoppers are eaten so sparingly, 2 stomachs,
both taken in June, contained nothing else, and another contained 97 per
cent of them.
Various insects and spiders, with a few other items, make up the rest of
the animal food, a little more than 5 per cent. Spiders are not important
in the oriole's food, but are probably eaten whenever found. They were
identified in 44 stomachs, but in small numbers. The scales of a lizard
were found in one stomach and the shell of a snail in another.
The vegetable contingent of the oriole's food is mostly fruit, especially
in June and July, when it takes kindly to cherries and apricots, and
sometimes eats more than the fruit grower considers a fair share.
However, no great complaint is made against the bird, and it is probable
that as a rule it does not do serious harm. With such a good record as an
insect eater it can well be spared a few cherries.