State and Federal Endangered
This bat (Family: Vespertilionidae) is Hawaiʻi’s only native terrestrial mammal. It is a tree-roosting bat and does not aggregate in large numbers.
The DLNR 2015 SWAP factsheet (snip from factsheet is below):
Here is a better photo:
Links to all USFWS documents related to the species, including a 1998 Recovery Plan: https://ecos.fws.gov/ecp0/profile/speciesProfile?sId=770
The 2015 SWAP shows the location of incidental records reported by the species up until publication of that document.
In more recent times the hoary bat was not reported on Oahu until studies associated with permits for the wind energy facilities showed that they were still present on Oahu. There are still no reliable estimates of the bat population on any island and some guesses for the state range as high as 2 orders of magnitude difference!
Several recent studies have investigated the history and evolution of the bat in Hawaiʻi. The most recent study recommends full species status for the Hawaiian Hoary Bat (it is still considered a subspecies as of 2020) and postulates based on evidence that there were at least two separate colonizations with one relatively recently, and one much older, with one study estimating about 1 M years ago (the population which that study recommend for full species status). That study by Baird et al. (2015) is here: https://academic.oup.com/jmammal/article/96/6/1255/1171864
Additional support for full species status for the Hawaiian Hoary Bat is the detailed description of differences from the mainland hoary bat provided in the PhD dissertation of D. Jacobs (1993) which can be found here: https://scholarspace.manoa.hawaii.edu/handle/10125/10331.
The US Geological Survey (USGS) has done much of the bat research in Hawaiʻi and is actively doing more research on life history, genetics, and prey of the species. Recent research on the bat is available here: https://dlnr.Hawaiʻi.gov/wildlife/esrc/hhb/.
Several of the more pertinent past studies are listed below.
Foraging Range Movements on Hawaiʻi Island: https://pubs.er.usgs.gov/publication/70144482
Behavior at wind turbines in Hawaiʻi: https://pubs.er.usgs.gov/publication/70155144
Other USGS publications on the Hawaiian Hoary Bat, such as monitoring results at specific sites, can be found here: https://www.usgs.gov/centers/pierc/publications
Research published in 2016 described a second species of bat in Hawaiʻi that is now extinct whose remains were found in a Maui lava tube in 1981. As explained on the Wikipedia page (https://en.wikipedia.org/wiki/Synemporion) “Synemporion keana is an extinct species of bat which lived in what is now Hawaiʻi from at least 320,000 years ago to around 2,100 years ago. It is the only species in the genus Synemporion.” More information is available at the website.