We exposed 13 species of waterbirds (Pelecaniformes, Ciconiiformes, Falconiformes) to the direct approach of an airboat to determine their flush distances. Five lakes with different levels of airboat activity were visited in central Florida during April-August 1999 to 2001. We detected considerable variation in flush distances among individuals within the same species and significant differences among species in response to an airboat. Average flush distances among all species ranged from 49 m for the Snail Kite (Rostrhamus sociabilis) to 172 m for the Bald Eagle (Haliaeetus leucocephalus). Average flush distances among herons ranged from 65 m for the Tricolored Heron (Egretta tricolor) to 113 m for the Great Egret (Ardea alba). Larger species generally exhibited greater average flush distances. A comparison of the flush distances elicited by a fast moving outboard-powered boat and an airboat indicated that all nine species exhibited significantly greater flush distances to the approach of an airboat. Recommended buffer zones that would minimize disturbance of waterbirds while foraging and loafing ranged from about 130 m (Snail Kite) to 365 m (Bald Eagle) for raptors and 165 m (Tricolored Heron) to 255 m (Great Egret) for wading birds.