Landbirds on offshore islands in samoa
2001
Freifeld, Holly B. | Steadman, David W. | Sailer, Jeffrey K.
We surveyed birds on seven small (<3 km²) offshore islands in the Independent State of Samoa to investigate the distribution and abundance of landbirds relative to abiotic and biotic features of these islands. We recorded 17 of the 28 indigenous species of landbirds that reside in Independent Samoa. Species richness among the islands ranged from 3 to 12 species. Other than the domestic chicken, none of the non-native species common on the large islands of ‘Upolu and Savai'i was recorded on offshore islands. Nu'utele, the third-largest of the seven islands, had the greatest proportion of native forest and harbored the most species of landbirds, including five not found on any other offshore island (Tooth-billed Pigeon [Didunculus strigirostris], West Polynesian Ground-Dove [Gallicolumba stairi], Pacific Pigeon [Ducula pacifica], Samoan Whistler [Pachycephala flavifrons], and Samoan Flycatcher [Myiagra albiventris]). The similarly sized Apolima, which is inhabited and extensively cultivated, had only six species, about the same as the much smaller but forested Namua. Manono, the largest island, also has the largest human population, and harbored 10 landbird species. These included two species not recorded on Nu'utele (Banded Rail [Gallirallus philippensis] and Purple Swamphen [Porphyrio porphyrio]), both of which prefer disturbed habitats to native forest. Habitat and human disturbance, rather than abiotic variables such as area and distance to the nearest island, are the primary factors influencing the distribution of birds on small offshore islands, especially those >1.0 km².
显示更多 [+] 显示较少 [-]