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Six archaeological sites up to 1000years old on Aitutaki, Cook Islands, have yielded bones of 15speciesof birds, five of which no longer occur ontheisland: Pterodromarostrata(Tahiti Petrel);Sula sula(Red-footedBooby); Dendrocygna,undescribedsp.(alarge,extinctwhistlingduck); Porzanatabuensis (Sooty Crake); and Vini kuhlii (Rimatara Lorikeet). Of these, only S. sula and P. tabuensis survive anywhere in the CookIslands today.The nearest record of anyspecies ofDendrocygnaisinFiji.Asidefrom theaquaticspeciesEgrettasacra (Pacific Reef-Heron) and Anas superciliosa (Gray Duck), the only native, resident land bird on Aitutakitoday isthe SocietyIslands Lorikeet(Viniperuviana), which may have been introduced from Tahiti. Residents ofAitutaki note that Ducula pacifica (Pacific Pigeon) and Ptilinopus rarotongensis (Cook Islands Fruit-Dove)also occurredthere until the 1940sor 1950s.There isno indigenous forest on Aitutaki today. The bones from Aitutaki also include the island's first record of the fruit batPteropus tonganus. Limestone caveson the island of Atiu yieldedthe undated bones of sixspeciesof birds, three of which no longer exist there or anywhere elsein the Cook Islands: Gallicolumba erythroptera (Society Islands Ground-Dove),Ducula aurorae (SocietyIslands Pigeon),and Vinikuhlii. Each of these specieshas been recovered from prehistoric sites on Mangaia as well. The limestone terrain of Atiu is mostly covered with native forest that supports populations of Ducula pacifica, Ptilinopus rarotongensis, Collocalia sawtelli(Atiu Swiftlet), and Halcyon tuta (Chattering Kingfisher). The survival of these land birds depends upon protection of Atiu's forests.

Between 1892 and 1930, 58 percent (30 taxa) of Hawaiian endemic forest birds either were greatly reduced or became extinct. The order in which the islands experienced major declines ofseveral forest birds is Oahu (ca. 1873-1887), Hawaii (1892-1900), Mo10kai (1893-1907), Maui (18941901), Kauai (after 1900), and Lanai (1926-1932). Loss of habitat, reduced food supply, introduced avian diseases, as well as predation by man, feral cats, mongooses, and Norway rats (Rattus norvegicus) all appear to have reduced some species ofbirds, but none ofthese factors adequately explains the accelerated rates ofdecline offorest birds that occurred after 1892. Although it has been assumed that roofrats (Rattus rattus) reached Hawaii with the first European ships at the end of the 18th century, there is circumstantial evidence, independent of the bird decline data, that indicates that this rat did not arrive until after 1840, probably between 1870 and 1880. The hypothesis is advanced that after its establishment on Oahu in the 1870s, R. rattus spread to the remaining large islands in the group, resulting in a stepwise accelerated decline offorest birds on each island in turn. Hawaii thus parallels some other Pacific islands where major reductions of birds have followed the establishment of R. rattus. The need for precautions to prevent rats from reaching rat-free islands in the Hawaiian group is emphasized.