HAWAIIAN HONEYCREEPER HOME RANGE SIZE VARIES WITH HABITAT: IMPLICATIONS FOR NATIVE ACACIA KOA FORESTRY

Abstract

Reforesting degraded landscapes with native, high‐value timber trees may contribute to biodiversity protection while also increasing the economic value of the land. Ideally, reforested areas should have the habitat characteristics to support viable populations of native fauna. We investigated habitat use by Akiapolaau (Hemignathus munroi), an endangered Hawaiian honeycreeper, in three habitat types: a relatively intact old‐growth forest, an old‐growth forest with a long history of grazing, and a native Acacia koa plantation. We quantified habitat characteristics, calculated foraging preferences, mapped home ranges, measured territoriality, and determined reproductive success at all sites. We found that Akiapolaau were highly selective foragers, foraging primarily on A. koa despite its relative scarcity in the environment, and then secondarily on several subcanopy species. Home range size was significantly smaller at the intact old‐growth site and the A. koa plantation, the two sites with the greater cover of A. koa and of the subcanopy species preferred by Akiapolaau. Birds at these sites were also less territorial, supporting behavioral theory that predicts a nonlinear relationship between food availability and territoriality. Overall, our results show that the A. koa plantation, the site with the highest percentage of A. koa, the smallest Akiapolaau home ranges, and the least territoriality, supported the highest density of birds with no apparent reproductive cost. Because A. koa is an extremely high‐value hardwood and thus can be selectively harvested, there is tremendous potential for conservation advocates to work with landowners to grow A. koa for economic benefit while also enhancing biodiversity.