Animals often eavesdrop on other species' alarm calls to gain information about danger, but this can allow for deception by callers. Such deception often uses 'aerial' alarm calls, which normally warn of airborne predators and prompt immediate fleeing. The calls are deceptive if they are given when no flying predator is present and the caller benefits from the victim's response, typically by gaining food dropped when the listener flees. We studied deceptive alarm calling by brown thornbills,