The purple martin is the biggest swallow that lives in the United States. In the eastern part of the country, this bird lives almost solely in birdhouses that are set up by citizens and conservationists. Like all swallows, the purple martin is an excellent flier, using this ability to both eat and drink.
The purple martin eats flying insects that it captures while in flight. It is capable of eating thousands of flying insects, catching them with its bill as it glides through the air.
Species of bugs that wind up on the purple martin's menu are moths, butterflies, common houseflies, grasshoppers and dragonflies, which are a favorite food.
Mosquitoes make up as little as 2 percent of a purple martin's diet, despite claims by birdhouse companies that exaggerate how many of the pests martins eat.
Purple martins also eat honeybees, but only those that occasionally fly high enough to become prey; martins do the majority of their hunting for insects quite high off the ground.
Many people will put out oyster shells and eggshells on a raised platform near a purple martin colony; the birds eat them quickly for an excellent source of calcium.