Demography and movements of the endangered Akepa and Hawaii Creeper

Abstract

We studied populations of the endangered Akepa (Loxops coccineus coccineus) and Hawaii Creeper (Oreomystis mana) at four sites on the island of Hawaii. Mean monthly density (± SE) of Akepa was 5.74 ± 0.87, 1.35 ± 0.41, 0.96 ± 0.13, and 0.76 ± 0.12 Akepa/ha at Kau Forest, Hamakua, Keauhou Ranch, and Kilauea Forest study areas, respectively. Hawaii Creepers were found at densities of 1.68 ± 0.53, 1.79 ± 0.42, 0.48 ± 0.06, and 0.54 ± 0.08 birds/ha, respectively, at the four study areas. Highest capture rates and numbers of birds counted from stations occurred from August through November and February through March. Hatching-year birds were captured from May through December for Akepa and April through December for Hawaii Creeper. Annual survival for adults at Keauhou Ranch was 0.70 ± 0.27 SE for 61 Akepa and 0.73 ± 0.12 SE for 49 Hawaii Creepers. Lowest rates of mortality and emigration occurred between May and August. Both species appeared to defend Type-B territories typical of cardueline finches, retained mates for more than one year, and showed strong philopatry. Home ranges for Hawaii Creepers (x̄ = 7.48 ha) were larger than those for Akepa (x̄ = 3.94 ha). No difference was found between home range sizes of males and females for either species.

Citation

Ralph, C. John; Fancy, Steven G. 1994. Demography and movements of the endangered Akepa and Hawaii Creeper. Wilson Bulletin 106(4):615-628