S43.2: Constraints to characterising spatial heterogeneity in a lowland forest avifauna in New Guinea

New Guinea. Two hundred and five bird species were recorded in lowland alluvial forest of the Basin: 170 breeding residents, 14 regular nonbreeding visitors, 10 local nonbreeding vagrants, and 11 migrants from Asia or Australia. The list includes 156 species of forest-dwelling birds, 82 of which are restricted to forest interior. No more than 171 species have been recorded from any single site. Surveys of less than two months ’ duration produced significantly incomplete species lists; the recommended minimum effort for comprehensive site-based surveys in lowland rainforest of Papua New Guinea is four months total effort spread over several seasons. Results from individual surveys were skewed by a range of effects, some of which include observer bias, seasonal changes in avian detectability, and habitat-based effects. Having accounted for these sampling biases, we then present evidence for local patchiness of distribution within the Basin. Examples of locally patchy species include the Common Paradise Kingfisher Tanysiptera galatea and the Rusty Pitohui Pitohui ferrugineus, which are abundant at most sites but absent or rare at others. Floristic and structural heterogeneity at several scales in the Basin forests is undoubtedly a factor influencing within-Basin distribution of forest birds, and yet the complexity of the pattern of forest heterogeneity has hindered our delineating the full nature and extent to which birds track local fores