Habitat relationships of forest birds on Tutuila Island, American Samoa

Aim Our knowledge of landbirds on tropical Pacific islands is often comprised of brief, one-time surveys. We know little of species' habitat preferences, and this information is critical for understanding the resource requirements or population status of native species and the impacts of human activity on island birds. Location Tutuila Island, American Samoa. Methods The spatial patterns in forest birds were investigated. This island harbours large tracts of native forest, a variety of disturbed and non-native forests, and some relatively healthy bird populations. The distribution of birds was correlated with forest types using habitat data collected at fifty-seven sites and avian census data collected monthly for 1-4 years at these sites. Results Differences in location and in vegetation structure and composition between native and non-native habitats are important influences on the distribution of birds on Tutuila. Among native species, for example, the purple-capped fruit-dove (Ptilinopus porphyraceus Temminck) is dependent upon native habitat, the Samoan starling (Aplonis atrifusca Peale) occurs in all habitats, and the cardinal honeyeater (Myzomela cardinalis Gmelin) is more abundant in low elevation, non-native habitat. Conclusions This research reinforces the importance of quantitative assessment of habitat relationships in the study and conservation of Pacific birds.