Avian Feeding Guild Composition in Papua Lowland Forest: A ComparativeAcross Habitat Types in Manokwari

Changes in forest cover from forest to non-forest systems alter habitat structure and resource availability, thereby affecting the functional composition of bird communities. This study aimed to identify and compare the structure of avian feeding guilds along a forest successional gradient in the lowland forest of Manokwari. Bird surveys were conducted using repeated point counts across six habitat types representing early (mixed shrub and agricultural habitats), intermediate (mixed plantation and young secondary forest), and late successional (old secondary and primary forest). Species were classified into feeding guilds based on their primary food. Guild species richness and relative abundance were calculated, and the effects of habitat succession on guild abundance were analysed using a negative binomial generalized linear mixed model. A total of 55 species belonging to 15 feeding guilds were recorded. Aerial frugivores contributed the highest proportion of species richness (21.82%), whereas insectivore–nectarivore showed the highest relative abundance (21.67%), followed by arboreal frugivores (20.77%) and nectarivores (20.31%). Bird abundance was markedly higher in intermediate and late successional habitats than in early successional habitats, indicating greater trophic resource availability in more structurally complex vegetation. The GLMM revealed significant effects of habitat succession (Wald χ² = 48.32, p < 0.001) and feeding guild (Wald χ² = 331.93, p < 0.001) on bird abundance, demonstrating a functional shift in trophic guild dominance along the successional gradient. These findings highlight the importance of intermediate and late successional forests in maintaining functional diversity and supporting key ecosystem processes in tropical lowland forests.