Juvenile dispersion and use of habitat by the endangered Kakerori Pomarea dimidiata (Monarchinae) on Rarotonga, Cook Islands

Abstract

The Kakerori (Rarotongan flycatcher) Pomarea dimidiata is a small, territorial passerine, endemic to Rarotonga, Cook Islands. Now listed as endangered, the total known population in August 1991 was 48 individuals. Kakerori are found in the steep, forested inland of southern Rarotonga. Newly fledged young remain high in the canopy near the natal nest. However, 4?5 months later they occupy spurs and small ridges immediately surrounding the parental territory, while 7?8 months after fledging, these young birds are most often found on high, exposed ridges where they form small cohorts. The daily activity budget for Kakerori is dominated by calling and looking, and the most common method of feeding is gleaning. Overall, successful territories (those that produce fledged young) have a lower canopy, fewer ferns, and trees with a larger total basal area, than unsuccessful territories (those that do not produce fledged young). Survival of this species depends on continued management of the population, including further research on habitat requirements and effective predator control.