Final Comprehensive Conservation Plan - U.S. Fish and Wildlife ...

Hakalau Forest National Wildlife Refuge
Comprehensive Conservation Plan
Management actions include the eradication of pigs and control of nonnative plants (Gorresen et al.
2005).
Management of the Mauna Loa Strip study area (elevation approximately 3,280-4,920 ft) by the
Hawai„i Volcanoes National Park includes the exclusion of ungulates (cows, goats, pigs, and sheep)
and the control of nonnative plants. The East Rift study area (1,640-3,280 ft) is comprised of wet
„ōhi„a-dominated forests. The portion of the study area that lies within the Hawai„i Volcanoes
National Park has received ungulate control. The adjacent area (i.e., Kahauale„a Natural Area
Reserve) has received no nonnative plant or ungulate control. The forest surrounding and including
parts of the study area have been extensively disturbed by lava flows, fire, and „ōhi„a dieback
(Gorresen et al. 2005).
Figure 4-5 shows the configuration of Forest Bird Survey Transect lines established at the Hakalau
Forest Unit (HFU) for annual bird surveys.
4.4.1 ‘Akiapōlā‘au (Hemignathus munroi)
The „akiapōlā„au is a medium-sized, stocky, short-tailed Hawaiian honeycreeper. Its bill has a long,
sickle-shaped upper mandible and a short, straight lower mandible that is only half as long as the
upper. Males are larger and heavier than females and have a slightly longer bill. Adult males have a
bright yellow head and underparts, a greenish back and wings, and black lores. Adult females differ
in color, with a yellowish-white chin, throat, and upper breast that contrasts with a pale yellowishgray
lower breast and belly. Fledglings have a mottled yellowish-gray or green plumage with pale
underparts.
The „akiapōlā„au is endemic to the Island of Hawai„i. Historically, the „akiapōlā„au was much more
common and widespread than it is today, being found virtually islandwide in native forest. In the
early 1900s, these forest birds were reportedly abundant, occurring in forests as low as 1,650 ft near
Hilo. In the 1940s, they were still present above 5,500 ft in Hawai„i Volcanoes National Park, but by
1970 they had disappeared from the Park and were less common elsewhere (Pratt et al. 2001a).
In the 1970s, „akiapōlā„au were found in five disjunct populations with a total estimated population
size of 1,500 ± 400 birds (confidence interval (CI) =95 percent) (Scott et al. 1986). Four of these
populations inhabited koa-dominated montane forests in Hāmākua south to the upper Waiākea
kīpuka, Kūlani, and Keauhou, in Ka„ū and Kapāpala, in southern Kona, and in central Kona. A fifth
population occupied subalpine dry forest on Mauna Kea. Originally these populations were all
connected, but they have since been isolated by clearing of forest, mainly due to grazing.
The most recent population estimate, based on islandwide surveys from 1990-1995, is 1,163 birds,
with a 90 percent CI of 1,109-1,217 birds (Fancy et al. 1995). However, more recent surveys indicate
that the population size might be greater.
4-16 Chapter 4. Refuge Biology and Habitats