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We investigated resource use by breeding Tricolored Herons (Egretta tricolor) and Snowy Egrets (E. thula) at a regional scale (1,312 km2) during three years (1987-1989) with dissimilar water levels. We documented the direction and distance flown from the colony to feeding sites, habitat selection, daily movement patterns, feeding flock size, and diet at the Rodgers River Bay colony in Everglades National Park, Florida. The general pattern of flight direction was similar between the two species; both species flew northwest in 1987, a wet year, and northeast in 1988, a year with moderate surface water drying. During drought conditions in 1989, only Tricolored Herons nested successfully. Despite similarities in flight direction, habitat selection differed between the two species. Tricolored Herons were more consistent in habitat use among years, whereas Snowy Egret habitat selection was more variable. However, shifts in habitat selection in response to varying hydrologic conditions among years were greater than differences in habitat selection between the two species within a year. Prey selection was similar for the two species in 1987, indicating that they procured similar prey from different habitat types. Regardless of water conditions, Snowy Egrets were significantly more gregarious than Tricolored Herons, and feeding sites on consecutive days by radio-tagged Snowy Egrets were farther apart than those used by Tricolored Herons. Our results suggest that habitat selection occurs at a coarser scale than previously recognized and that studies conducted at single sites over short temporal scales may be ignoring important aspects of habitat selection.