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

Hakalau Forest National Wildlife Refuge
Comprehensive Conservation Plan
In the central windward region of Hawai„i, common „amakihi trends are stable or increasing at the
upper elevation study areas such as Kūlani-Keauhou and the Mauna Loa Strip; however, they are
trending downward at lower elevation sites such as „Ōla„a and East Rift. Between 1995-2003,
common „amakihi density increased at Kūlani-Keauhou from 1.3-1.6 birds per acre. From 1977-
1994, common „amakihi showed a stable trend at the Mauna Loa Strip (1.8 birds per acre). Common
„amakihi were absent at „Ōla„a throughout the survey period (1977-1994) and nearly absent at East
Rift (0.008 birds per acre from 1979-1994) (Gorresen et al. 2005).
Elevational changes in distribution in the common „amakihi have also been documented. While
„amakihi are uncommon lower than 1,640 ft (Scott et al. 1986), range expansion of the „amakihi to
lower elevations has been documented in the Puna district located on the southeastern corner of
Hawai„i Island. Common „amakihi are the most common native birds in these areas of active malaria
transmission (Spiegel et al. 2006, Woodworth et al. 2005).
At the HFU, common „amakihi attained highest densities in the higher elevation portion of the unit
above 4,900 ft. These densities occurred in a range of habitats including grassland, closed canopy
forest with a koa component, banana poka-infested stands, and heterogeneous habitats along the
forest margins. The species were absent or occurred at low densities in the wet forest with tree fern
and matted fern. Common „amakihi densities were positively associated with koa and species
richness, and negatively associated with nonnative vegetation and rainfall (Camp et al. 2003).
Common „amakihi are found at the KFU and are present at all elevations (Atkinson et al. 2005).
The common „amakihi is a year-round inhabitant of a wide range of native dry shrublands and dry,
mesic, and wet forests in montane and subalpine communities (Scott et al. 1986). The species is also
a characteristic bird of „ōhi„a forests (Lindsey et al. 1998).
Common „amakihi are generalized foragers that most often glean arthropods from the leaves,
blossoms, twigs, branches, and less frequently from tree trunks of a variety of trees, ferns, and
shrubs. They feed on nectar predominately from the flowers of „ōhi„a, māmane, and native lobelias
(Campanulaceae), but also forage on flowers of a number of other native and nonnative plants.
Common „amakihi also eat fruit from native and nonnative plants, but predominately from pilo
(Mitchell et al. 2005).
Common „amakihi breed from December-July on the Island of Hawai„i (Lindsey et al.1998, van
Riper 1987). In dryland māmane-naio forest, māmane trees are the preferred nesting substrate; of
174 nests, 88 percent were found in māmane trees and 12 percent were detected in naio (van Riper
1987). In mesic and wet forests, „amakihi use „ōhi„a trees almost exclusively for nesting (Kern and
van Riper 1984).
Common „amakihi are range limited because of loss and destruction of native forests, the presence of
malaria at lower elevations, and predation by mammals. Mortality of „amakihi experimentally
infected with the malaria parasite was 65 percent. While „amakihi are uncommon under 1,640 ft,
range expansion of the species to lower elevations has been documented at Puna, where they are the
most common native birds in these areas of active malaria transmission (Spiegel et al. 2006,
Woodworth et al. 2005). Common „amakihi are also found at lower elevations in the KFU (Atkinson
et al. 2005). Common „amakihi in these low-elevation areas show malaria prevalence levels of up to
80 percent and were also more likely to be infected with pox (Atkinson et al. 2005, Woodworth et al.
4-34 Chapter 4. Refuge Biology and Habitats