Humans visiting natural areas often disturb wildlife, possibly displacing animals from desirable habitat. To hold ecotourt, cm at acceptable levels refuge managers need to know which species are likely to be affected and which response occurs at different levels of disturbance. Displacement of waterbtrds at J. N. "Ding" Darling National Wildlife Refuge, Florida (ZL.S_4.), by specific human activities was demonstrated experimentally by Klein in 1993. We assessed the extent of this effect of ecotourism on the distribution of 38 species of waterblrds by surveying birds in plots of known distance from a dike along which wildlife tours occurred. Most resident species were less sensitive to disturbance than were migrants. Migrant ducks were most sensitive when they first arrived, mid-October to mid-December, usually remaining more than 80 m from the drive, even at low levels of human visitation. Herons, egrets, Brown Pelicans (Pelecanus occidentalis), and Anhingas (Anhinga anhinga) were most likely to remain close to areas of high human activity. Shorebtrds were displaced at intermediate distance and visitation levels. Mottled Ducks (Atlas fulvigula) and several of the ardetds seemed to include two groups differing in behavior, one habituated to humans and one sensitive to disturbance. Public education and changes in management practices are needed to reduce disturbance. Guided tours and low-disturbance zones where people stay in their cars could reduce the negative effects of tourists, especially in the fall when migrants arrive. The number of human visitors may have to be reduced or the wildlife drive closed on certain days during the tourist season.El efecto del ecotourismo en la distribuci6n de las aves acufiticas de un refugio de vida silvestre Resumen: La visita de seres humanos a ~reas naturales perturba frecuentemente la vtda sllvestre, posiblemente desplazando antmales de los hdbitats apropiados. Para mantener el ecoturismo a niveles aceptables, los administradores de refugios tienen que saber que espectes pueden ser afectadas y cuales son las respuestas a los distintos niveles de perturbaci6n. El desplazamiento de aves acudttcas por actividades humanas espectftcas, en el Refugto Nacional de Vida Silvestre J. N. "Ding, " en Florida (U.Sdl.), fue demostrado experimentalmente por Klein en 1993. En el presente estadto evaluamos la extensi6n de los estos efectos del ecoturismo sobre la distribuci6n de 38 especies de aves acuAticas. Estudlamos aves en parcelas que se encuentran a una distancia conocida de una represa, a lo largo de la cual se llevaban a cabo excursiones. La mayorfa de los eso pecies residentes, fueron menos sensibles a la perturbaci6n que las especies migratorias. Los paros migratorios fueron los mds sensibles cuando reci#n llegaron, de medlados de Octubre a medtados de Dtclembre, permaneciendo usualmente a md.s de 80 m. del sendero, at~n cuando los niveles de las visitas por seres humanos eran bajos. Las garzas, los atrones, los pellcanos cafes (Pelecanus occidentalis), y (Anhinga anhinga) fueron ...