like all swifts, the chimney swift forages on the wing. studies have shown that of its food items are flying insects, including various species of flies, ants, wasps, bees, whiteflies, aphids, scale insects, stoneflies and mayflies. it also eats airborne spiders drifting on their threads. it is an important predator of pest species such as the red imported fire ant and the clover root curculio. researchers estimate that a pair of adults provisioning a nest with three youngsters consume the weight equivalent of at least insects per day. like many bird species, the chimney swift periodically coughs up pellets composed of indigestible bits of prey items.