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

Hakalau Forest National Wildlife Refuge
Comprehensive Conservation Plan
success. They create either open water nests or nests in emergent vegetation. Nesting occurs yearround,
but most activity occurs March-September. Eighty percent of the population occurs on Kaua„i,
but they are found on all the main Hawaiian Islands (with the exception of Kaho„olawe). The
population is stable and estimated to be 2,000-4,000. Similar to the rest of the Hawaiian waterbirds,
threats to „alae ke„oke„o are habitat loss, nonnative mammalian predators such as mongooses, rats,
cats, barn owls, etc., altered hydrology (modified wetlands), nonnative invasive plants, and avian
diseases (e.g., botulism). Though rare, „alae ke„oke„o are known to be present at the ponds at HFU
(Mitchell et. al, 2005).
4.7 Endangered Mammal
4.7.1 ‘Ōpe‘ape‘a (Lasiurus cinereus semotus)
The endangered „ōpe„ape„a is the only extant native land mammal in the archipelago. Both males and
females have a wingspan of approximately 1 ft, and females are typically larger bodied than males.
Both sexes have a coat of brown and gray fur. Individual hairs are tipped or frosted with white.
Population estimates for all islands have ranged from hundreds to a few thousand. Since no accurate
population estimates exist for this subspecies and because historical information regarding its past
distribution is scant, the decline of the bat has been largely inferred. „Ōpe„ape„a have been regularly
sighted in Kaua„i, Hawai„i, and Maui (Menard 2001).
Changes in seasonal abundance of „ōpe„ape„a at locations of different elevations indicate that
altitudinal migrations occur on the Island of Hawai„i. During the breeding period (which begins as
early as April), „ōpe„ape„a occurrences increase in the lowlands and decrease at high elevation
habitats, such as the HFU. „Ōpe„ape„a occurrences are especially low from June-August in high
elevation areas. In October, during the post-lactation period, bat occurrences increase at the HFU and
in the central highlands. In January, bat occurrences at HFU also increase, possibly receiving
„ōpe„ape„a from both the lowlands and central highlands (Menard 2001).
Echolocation studies in the Pua „Ākala tract at the HFU confirm these observations. The area has
moderate use (less than 40 bat call pulses per week sampled) by „ōpe„ape„a between May-June.
However, bat activity at Pua „Ākala dramatically increases during fall and winter (August-March)
such that this area may be considered an important „ōpe„ape„a wintering ground for „ōpe„ape„a from
many parts of the island (Bonaccorso 2008).
„Ōpe„ape„a roost in native and nonnative vegetation from 3-29 ft above ground level. They occur in
both wet and dry areas of the island but are believed to be more abundant on the drier leeward side
(Jacobs 1994). „Ōpe„ape„a have been found roosting in „ōhi„a, hala, coconut palms, kukui, kiawe,
avocado, shower trees, pūkiawe, and fern clumps; they are suspected to roost in eucalyptus and Sugi
pine stands. The species is rarely observed using lava tubes, cracks in rocks, or manmade structures
for roosting. While roosting during the day, „ōpe„ape„a are solitary, although mothers and pups roost
together (USFWS 1998c, Mitchell et al. 2005).
„Ōpe„ape„a feed on a variety of native and nonnative night-flying insects, including moths, beetles,
crickets, mosquitoes, and termites (Whitaker and Tomich 1983) but may have a preference for moths
4-44 Chapter 4. Refuge Biology and Habitats