FISHES EATEN BY SOOTY TERNS AND BROWN NODDIES IN THE DRY-TORTUGAS, FLORIDA

Fish prey items sampled over a 50-year period from Sooty Terns (Sterna fuscata) and Brown Noddies (Anous stolidus) in the Dry Tortugas, Flor ida, were compared. Samples were from the nesting seasons during three time periods: 1920-1941, 1960-1964 and 1974-1976. Eighty-four species from 33 families were identified, showing a wide diversity in feeding . However, 13 families represented by at least 14 species composed the basic diets of these birds because they occurred during all three sam pling periods. Ten of these are families of species that are either pe lagic and open-ocean throughout their lives or species that have pelag ic post-larvae or juveniles, the life stages preyed upon by the terns. Nine of these families are also found in the diets of Sooty Terns and Brown Noddies on Christmas Island, Pacific Ocean, and the Hawaiian Is lands. The terns of the Dry Tortugas appear to be unique in that for a t least the last 50 years they have exploited several reef-oriented sp ecies, including two species of benthic, burrow-dwelling fishes, the o pistognathid Lonchopisthus micrognathus and the gobiid Bollmannia boqu eronensis. Neither of these terns dives and both of these fish species apparently never come near the surface. They are brought to the surfa ce and made available to the terns by shrimp trawlers as part of their bycatch.