Most of us have been taught that birds do not eat monarchs. In fact, if a bird just happens to try to make a meal out of a monarch, it gets sick from ingesting the poisonous compounds that course through the monarch’s body. After living through such an experience most birds do not try to dine on a monarch again.
Eastern bluebirds are an exception to the rule. These gorgeous backyard favorites eat monarch caterpillars laden with poisonous chemicals obtained when they chomp on milkweed plants without showing any ill effects.
The bluebird can devour this toxic food because it uses a technique to prepare a caterpillar before it tries to consume it. Once a bluebird grabs a monarch caterpillar it flies to a branch and squeezes the large, juicy caterpillar time and time again. This process forces much of the juicy innards of the caterpillar out both ends of its body. Once the caterpillar has been flattened, the hungry bluebird then proceeds to eat the hapless insect.