mississippi kites, peregrine falcons and merlins are raptors that are known to take adult chimney swifts in flight, being among the select few avian hunters fast enough to overtake the appropriately named swift on the wing. eastern screech-owls have been seen attacking colonies, as have non-avian predators including eastern rat snakes, northern raccoons and tree squirrels. these are most likely to take nestlings but may take some nesting adults as well. when disturbed by potential predators (including humans) at the colony, adult chimney swifts slap their wings together after arching back and taking flight, making a very loud noise known either as "booming" or "thunder noises". when disturbed, nestlings make a loud, raspy "raah, raah, raah" sound. both sounds seem designed to startle potential predators.