253.

Hawaiian Hoary Bat

Lasiurus semotus

French: Lasiure d'Hawai / German: Hawaii-Haarschwanzfledermaus / Spanish: Lasiuro de Hawai

Taxonomy. Atalapha semota H. Allen, 1890,

“Sandwich Islands [= Hawaii, USA].”

See L. egregius . Lasiurus semotus is in the Hoary Bat group. Monotypic.

Distribution. Endemic to Hawaii.

Descriptive notes. Head—body 51 mm,tail 46 mm, ear 8 mm, forearm 40 mm (type specimen); weight ¢.16- 5-18 g. Females J larger than males. The Hawaiian Hoary Bat is smaller than its continental congener, the Northern Hoary Bat ( L. cinereus). Head and neck are brown-ash, with warm sepia band across neck and shoulders. Dorsal hairs have black bases, pallid distal bands, and rusty brown tips. Ventral hairs have black bases, whitish distal bands, warm sepia just below tips, and gray tips. Ears are short and rounded, furred on posterior surfaces; tragus is short and broad. Lips and cheeks are covered with black fur. Uropatagium is densely and uniformly furred through most ofits length, with russet-brown or rusty red hairs; marginal onethird can be sparsely furred. Skull is large and broad; rostrum is broad, with wide nasal openings; and auditory bullae are large. Teeth are large; P*is present and reduced, sometimes absent. Dental formula is11/3,C1/1,P 2/2. M 3/3 (x2) = 32. Chromesomal complement has 2n = 28 and FN = 48, with medium-sized submetacentric Xchromosome and small acrocentric Y-chromosome.

Habitat. Dry and wet areas and more frequently open and mixed habitats; partly wooded areas with clearings formed by pastures or lava flows; and sparsely vegetated or barren deserts from sea level up to elevations ¢. 4400 m (more common below 1200 m).

Food and Feeding. The Hawaiian Hoary Bat feeds completely on flying insects; gleaning from foliage or ground has never been observed. In open areas,it uses rapid and less maneuverable flight, with mean speed of 11- 3 m /s; in closed spaces, it uses slower and more maneuverable flight, with mean speed of 6- 5 m /s. It forages over streams and ponds near seashore, near lights, and over open ocean up to 100 m offshore. Groups of Hawaiian Hoary Bats were observed foraging in regular circuits, with individual airspaces for each individuals, flying 1-150 m aboveground, more commonly at 1-15 m. Analyses of stomachs, intestines, and feces showed dominance of beetles but also several orders of insects: Coleoptera (25-3% by volume), Homoptera (17-8%), Hemiptera (13-8%), Lepidoptera (12:4%), Isoptera (10-6%), Diptera (8-:4%), Orthoptera (8:2%), and Hymenoptera (0-4%). Other fecal analyses showed a majority of moths in the diet, followed by Coleoptera and Diptera .

Breeding. A pregnant Hawaiian Hoary Bat with two embryos was caught in May.

Activity patterns. The Hawaiian Hoary Batis crepuscular/nocturnal. Individuals have been observed flying as early as two hours before sunset and are commonly seen flying after sunset or after the sun has gone behind mountains. No activity peak has been identified, and individuals continued flying at least seven hours after sunset. Roosts include branches of screwpine ( Pandanus, Pandanaceae) by the seashore, exposed tree roots, lava caves, and collapsed lava tubes. Echolocation search-calls are FM signals, with harmonic complements of 8 milliseconds duration. Calls have maximum spectral intensity at 27-8 kHz, and frequency modulation from 37-1 kHz to 25-4 kHz, with no CF components.

Movements, Home range and Social organization. Hawaiian Hoary Bats have been observed flying over barren areas 11- 2 km from nearest woods. Radio-tracked individuals foraged as far as 13 km from day roosts and showed strong fidelity to roosts. Mean foraging area was 230-7 ha, and mean core area was 11-1% of foraging areas or 25-5 ha. Core areas might be continuous or several small patches. In winter, the Hawaiian Hoary Bat seems to migrate from lowland rainforests that are occupied in summer and autumn to interior highlands.

Status and Conservation. Not assessed on The IUCN Red List. The Hawaiian Hoary Bat is listed as endangered by the US Fish and Wildlife Service, based on apparent population decline and limited knowledge aboutits natural history.

Bibliography. Allen (1890b), Anderson (2002), Baird et al. (2015), Baker & Patton (1967), Baldwin (1950), Belwood & Fullard (1984), Bickham (1979a), Bonaccorso et al. (2015), Fujioka & Gon (1988), Jacobs (1996, 1999b), Novaes, Garbino et al. (2018), USFWS (1998), Whitaker & Tomich (1983).