ʻōpeʻapeʻa
The Hawaiian hoary bat (Aeorestes semotus ), also known as ʻōpeʻapeʻa, is a species of bat endemic to the islands of Hawaiʻi. Whereas the mainland hoary bat (A. cinereus ) is found throughout North America, the Hawaiian hoary bat is distributed only among the major volcanic islands of Hawaiʻi, making it the only extant and native terrestrial mammal in the state; although some studies also posit that the mainland hoary bat lives in sympatry on the Hawaiian Islands alongside the Hawaiian hoary bat, this has been disputed. The Hawaiian hoary bat was officially named the state land mammal of Hawaiʻi in 2015. It is a federally listed endangered taxon of the United States.
Like many species of bats, Hawaiian hoary bats are brown in color. However they are distinguished by the silver coloration that ‘frosts’ the fur on their back, ears, and neck. They typically weigh between 14 to 18 g (0.49 to 0.63 ounces), and have a wingspan of about 10.5 to 13.5 inches, with females being larger than males. They are insectivorous, nocturnal, and forage and hunt using echolocation. They are a solitary subspecies and roost individually rather than in colonies. They are found throughout a large range of different habitats - forests, agricultural fields, and areas populated with humans. Due to their elusive and solitary nature, there is very limited knowledge on the ecology or life history of the bat. As of now, population sizes are unknown, which is problematic because this data is necessary for species recovery plans. Currently the Hawaiian hoary bat is listed as endangered under the Endangered Species Act.
Regarding conservation, the Hawaiian hoary bat faces a number of possible threats including: habitat loss, collisions with man-made structures such as wind turbines and barbed wire, impact of pesticides on primary food source, predation and competition with invasive species, and roost disturbance and tree cover reduction.
The Hawaiian hoary bat is the only extant and native terrestrial mammal found in Hawaiʻi. Like many species of bats, Hawaiian hoary bats are brown in color. However, they are distinguished by a silver tint along the brown fur of their backs. More pronounced silver bands are found along the necks as the fur transitions to a yellowish brown along the face with the ears retaining a black edging around their perimeter. The common name of hoary bats was inspired by the hoary, or frosty, the coloration of their coats. Females of this species are larger than males.
These bats are native to the islands of Hawaiʻi. They are found in landscapes including human-populated areas, forests, agricultural fields, pastures, and even near mountain summits. During the warmer months, bats will travel to lowland environments where they will be more active. During the colder months, Hawaiian hoary bats travel to highland environments where they are not as active.
Hawaiian hoary bats are solitary and prefer to roost individually rather than in colonies. They are nocturnal hunters, usually hunting for food just before sunset and returning to their nests just before sunrise. Like other bats, they capture and eat their prey while still in flight. Bats do not have keen eyesight to spot their prey; rather, they use echolocation. By foraging using echolocation, bats can catch their target while in flight. The bats’ flight patterns differ in accordance to the environment they are hunting in and the prey they are hunting. When hunting in open environments (i.e pastures or above the canopy) where larger prey is more abundant, they will fly faster with less maneuverability. When hunting in closed environments (i.e clustered forests) where smaller prey is more abundant, they will fly slower to allow for more maneuverability to catch their elusive prey. While foraging, Hawaiian hoary bats can travel up to 19 km (12 miles) a night.
Hawaiian hoary bats are carnivores (insectivores) preying on insects for their source of food. They feed mainly on moths and beetles, but also eat crickets, mosquitoes, termites, and many other insects.
Hawaiian hoary bats are serially monogamous. They don’t mate for life but have a new partner each mating season. They follow a seasonal reproductive cycle. Mating occurs from October to November. The gestation period begins in May and ends in June when the lactation period begins. Pups are born at the end of August and will remain in the mother’s roosting nest until they become independent in 6 to 7 weeks. Female Hawaiian hoary bats usually give birth to twins.
The main threats to Hawaiian hoary bats include habitat loss, collisions with man-made structures such as wind turbines and barbed wire, the impact of pesticides on the primary food sources, predation and competition with invasive species, roost disturbance, and tree cover reduction.
Due to their elusive and solitary nature, there is little research on the life history of the Hawaiian hoary bat. According to a Wikipedia resource in 2005, it was estimated that the population size of this species ranged from a few hundred to a few thousand individuals, but this was based on incomplete and inadequate data. As of January 2020, population sizes and estimates are still unknown. Presently, the Hawaiian hoary bat is not included in the IUCN Red List and its conservation status has not been evaluated.
