In 1997, the Fish and Wildlife Service purchased an additional of land to create the Kona Forest Unit of Hakalau Forest NWR. The Kona Forest Unit includes lands within the Hoʻokena and Kalahiki land divisions on the western slopes of Mauna Loa, at elevations of . One of the primary purposes for the creation of this unit was to protect the habitat of the ʻalalā (Corvus hawaiiensis), which is now extinct in the wild.