Second Progress Report June-July ATF 1964 During the second 31 days of the trip 14 days were spent ashore while 17 days were spent at sea or in Pago Pago. Six islands were visited during this period and, with the exception of Hull Island, complete bird and plant surveys were made. Insect collections were made where needed to fill in previous collections and ectoparasites were collected off of as many species as possible. 409 blood samples were taken, 105 birds collected, 40333 birds banded with 3164 returns being obtained, plant collections were made on all islands and fish collections were made on three islands. Further evidence was gained during the second half of the trip regarding the importance of cats as a limiting factor on bird distribution. In the Oct.-Nov. preliminary report it was proposed that presence of cats on an island would prevent the breeding of petrels, shearwaters, or small terns. Evidence from the last trip (Feb.-Mar.) indicated that cats in large numbers would eliminate Red-footed Boobies, Frigates and possibly Blue-faced Boobies from an island. Efforts by the Smithsonian party on Howland, Baker and Enderbury have been directed toward the complete elimination of cats on these islands. The rather immediate response of the birds to the elimination of cats has been quite surprising. On Howland, where the last cat was eliminated in February, we found two species of the shearwater-petrel group looking for nest sites or sitting on the ground and one species of small tern nesting for the first time in our experience. On Baker where the last four cats were eliminated this July we found ten nests of Blue-faced Boobies and one nest of a Red-tailed Tropicbird plus a number of Gray-backed Tern nestlings. None of these birds had been found nesting on previous visits. On Enderbury Island, where the last three