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**History and General information on the Hawaiian Hoary Bat (Lasiurus cinereus semotus)**

On the remote Hawaiian island archipelago there lives an endemic land mammal, the Hawaiian Hoary Bat (Lasiurus cinereus semotus) which is a member of the family Vespertilionidae or common vesper bat (Honolulu Zoo, 2007 [1]). The Hawaiian Hoary bat is considered a subspecies of the North American Hoary bat which is considered the most widespread bat in the continental United States (Shump and Shump, 1982). The Hoary bat is named after the animal’s appearance. "Hoary" describes the fur of the bat, which is brown and grey, tinged with white, so that the bat looks "frosty." When the bat was first discovered by the native Hawaiian inhabitants it was named “Opeapea” which refers to the bats half taro leaf, canoe sail body outline (Honolulu Zoo, 2007). The Hawaiian Hoary bat weighs between 5-8 ounces.The Hawaiian Hoary Bat is solitary, nocturnal and feeds on insects. In a single night the Hoary bat can eat up to its own weight in insects (Honolulu Zoo, 2007). The female bats are larger than the males with a wing span of approximately 10.5-13.5 inches (USFWS 2007). It has been documented by the fossil record that the Hawaiian Hoary Bat was once present on the islands of Hawaii, Molokai, Maui, Oahu, and Kauai, but now they have only been documented as breeding on the islands of Hawaii and Kauai. A complete extinction of Hawaiian Hoary Bats on the island of Oahu was hypothesized to be due to a loss of habitat brought upon by the land change to accommodate humanity in the 19th century (Tomich, 1986). Much of the forest was cut down to make room for houses and buildings. On top of habitat change, the Hawaiian Hoary Bats populations appear to be indirectly affected by the use of pesticides, but the mechanisms of this effect are as of yet, unknown (USFWS 1998).

The Hawaiian Hoary Bat: Listed as endangered

In 1970, the Hawaiian Hoary Bat was listed as endangered under the Endangered Species Conservation Act of 1969 (USFWS, 1970), which was later replaced by the Endangered Species Act of 1973. ([2]) Under section 3 of the Endangered Species Act, an “endangered species” is any species or subspecies that is “in danger of extinction throughout all or a significant portion of its range.” The exact numbers of Hawaiian Hoary bats is unclear and remains unknown. The decision to add the Hawaiian Hoary bat to the endangered list seems to have been precautionary (Fuller, 1989a) and motivated by its rapid extinction on the island of Oahu, and the loss of forest habitat in the bat’s range (USFWS 1998). Till this day, the decision to list the Hawaiian Hoary Bat as endangered is controversial. According to Fuller, who in 1989 surveyed the island of Kauai for Hawaiian Hoary bats, “the Hawaiian Hoary Bat is deserving of its endangered status” On the other side, S. Scott claims in his article written in Plants and Animals of Hawaii that “although the Hawaiian Hoary Bat is on the federal endangered list, it may not truly be endangered.” Until exact numbers of the Hawaiian Hoary bats are found, uncertainty over whether or not the bat should be listed as endangered is a matter of opinion. However, since the Hawaiian Hoary Bat was listed in the 1970s, conservation is underway by the Nature Conservancy, the US Fish and Wildlife Service, and independent researchers.

Recovery plan and current conservation methods in use

The US Fish and Wildlife Service has appropriated a recovery plan for the Hawaiian Hoary Bat ([3]). The goal of the recovery plan is to de-list the Hawaiian Hoary Bat from endangered status to threatened status (USFWS: Recovery Plan 1998). However, due to the lack of understanding of the life history of the bats, more information is needed before any decision is made to de-list the bat. According to the recovery plan, all islands that have Hawaiian Hoary Bats must have increasing populations for at least 5 consecutive years to be considered for down-listing to threatened status (USFWS: Recovery Plan 1998). New methods are being infiltrated to try and get a good estimate of the population numbers of Hawaiian Hoary Bats. One method that is looking promising is monitoring the bats echolocation calls. Unlike most parts of the world where there are other species of bats whose calls would interfere with the Hoary Bat’s echolocation transmissions, the Hawaiian Hoary Bat is the only species of bat in Hawaii, and thus any echolocation ([4]) that is heard and recorded must be from the Hawaiian Hoary Bat (Fenton et al. 1994). So far, echolocation monitoring has worked well because it is non-obtrusive to the bats, which is important when working with an endangered species (Fuller. 1989b). Another approach that is being looked into is that of putting GPS satellite receivers on the bats to try and gain a better understanding of their life histories and strategies. However, since the bats are small it is hard to outfit them with trackers without potential side effects of the already endangered bat (USFWS 2007).

Outlook for the future of Hawaiian Hoary Bats

Although not much reliable information is known about the Hawaiian Hoary Bat, its prognosis for survival seems high due to the facts that: it is found on multiple islands, there have been frequent individual sightings, and it can be found in both native and non-native plant habitats, which shows diversity in livable habitats (Nature Conservancy Website, 2007) ([5]). For these reasons, the conservation of the Hawaiian Hoary Bat seems probable, and possible. By the year 2010, the US Fish and Wildlife Service hopes to have down-listed the Hawaiian Hoary Bat as threatened, and not endangered (USFWS: Recovery Plan 1998).

Literature Cited

1. Fenton, MB, Rautenbauch, IL, Smith, SM, Grossel, J and van Jaarsveld, J. 1994 Bats and Raptors: Threats and Opportunities. Animal Behaviour Vol: 48. Pg 9-18.

2. Fullard, JH 1989a Opeapea: Hawaii’s elusive native bat. Bats Vol: 17(3) Pg 10-13.

3. Fullard, JH 1989b Echolocation survey of the distribution of the Hawaiian Hoary Bat (Lasiurus cinereus semotus) on the island of Kauai. Journal of Mammalogy. Vol:70 Pg. 424-426.

4. The Nature Conservancy in Hawaii: http://www.nature.org/wherewework/northamerica/states/hawaii/science/art2417.html

5. Scott, S. 1991 Plants and Animals of Hawaii. Bess Press, Honolulu, Hawaii.

6. Shump, KA Jr. Shump, AU. 1982 Lasiurus cinereus. Mammalian Species. No:185 Pg 1-5.

7. Tomich, PQ. 1986 Mammals in Hawaii (2nd edition). Bishop Museum Press, Honolulu, Hawaii.

8. US Fish and Wildlife Service 1970. Appendix D-United States list of endangered native fish and wildlife. Federal register, 35: 16047-16048.

9. US Fish and Wildlife Service 1998. Recovery Plan for the Hawaiian Hoary bat. US Fish and Wildlife Service. Portland, OR.

10. US Fish and Wildlife Service Website 2007. http://www.fws.gov/pacificislands/wesa/hrybatindex.html

11. The Honolulu Zoo: http://www.honoluluzoo.org/hawaiian_bat.htm. 2007.