Breeding season diet of Scarlet Ibises and Little Blue Herons in a Brazilian mangrove swamp

We studied the diet composition and overlap of Scarlet Ibises (Eudocimus ru ber) and Little Blue Herons (Egretta caerulea in a mangrove swamp in southe ast Brazil during the 1996-1997 breeding season, which occurs during the ra iniest period. Crabs comprised 95% of all prey taken by the ibises and 80% of the prey of the herons, Nevertheless, diet overlap was small (similar to 30%) due to ibises feeding mostly on Uca spp. and Eurythium limosum crabs, which were taken from their burrows; the herons fed on the arboreal and se mi-arboreal Aratus Pisonii and Metasesarma rubripes crabs. Divergent huntin g strategies of ibises (tactile foragers) and herons visually-oriented pred ators) explains the diet segregation when preying on an ecologically divers e crab guild, but it is unclear why herons prey rarely on fiddler crabs. Sc arlet Ibises bred successfully while feeding oil estuarine organisms living in low salinities in the mangroves, showing that mangroves may be adequate foraging habitats for chick-rearing ibises during periods of low salinity.