.--On 15 June 1973 while on Enderbury Island (3 ø 08' S, 171 ø 05' W) in the central Pacific Ocean, I made some observations of an unusual feeding habit of the Gray-backed Tern (Sterns lunata). Initially about 5 adult terns were seen swooping low over an area of coarse coral rubble sparsely covered by low bushes (Sida/allax), a prostrate herb (Boerhavia cliffusa), and dry moribund clumps of a bunch grass (Lepturus repens). The first bird I saw clearly rose from a swoop with a lizard in its beak. The lizard was ahnost certainly a snake-eyed skink (Cryptoblepharus boutoni) because the only other species of lizard found on Enderbury, the mourning gecko (Lepidodactylus lugubris) is nocturnal. Another tern, which I watched for about 8 rain caught skinks on 2 of 3 swoops. At least twice during this period the tern made in- complete swoops probably because the lizard had seen the tern and had taken evasive action. Captured lizards were held across the mid-body and swallowed head first while the birds were in flight. As far as is known, the normal diet of this species consists primarily of small fish and squid (Munro, Birds of Hawaii, 1944; Pacific Ocean Biological Survey Program, unpubl. data filed at the U.S. National Museum of Natural History). Small crustaceans and insects are also eaten but apparently quite uncommonly (POBSP, unpubl. data). None of the species of terns treated in Bent (U.S. Natl. Mus. Bull. 113, 1921) was noted as having fed on lizards. However, Rowher and Woolfenden (Wilson Bull. 80:330-331, 1968) reported green anoles (Anolis carolinensis) in the digestive tracts of 4 of 6 Gull- billed Terns (Gelochelidon nilotica) collected in Florida. As these authors have indicated eating of lizards by this species was also noted by Jensen (Dan. Ornithol. Foren. Tidsskr. 40:82-83, 1946). Anderson (Dan. Ornithol. Foren. Tidsskr. 39:199, 1945) also recorded Gull-billed Terns eating lizards (Lacerta vivipara and L. agilis). Such a feeding habit of the Gray-backed Tern is apparently unusual because no mention of it is made in the extensive files of the Smithsonian Institution's Pacific Ocean Bio- logical Survey Program. Further, none of the Gray-backed Tern stomachs collected for the Program held anything other than that indicated above. It seems likely that this feeding pattern was an opportunistic response to the great abundance of these lizards on Enderbury at that time.--RogER B. CLAPP, National Fish and Wildlife Laboratory, National Museum o] Natural History, Washington, D.C. 20560. Accepted 8 May 1975.