This data release includes data and metadata on bird-mediated and passive seed rain for sites selected to have a range of understory cover under canopy trees (Metrosideros polymorpha and Acacia koa). All sites were within Hakalau Forest National Wildlife Refuge on Hawaii Island. Broadly, this study asks what thresholds of seed rain and native and exotic plant cover are needed for passive forest regeneration. Quantifying natural seed rain rates in different habitat types was needed to better understand how these thresholds function.