65.

Eastern Cave Bat

Vespadelus troughtoni

French: Vespertilion de Troughton / German: Troughton-Waldfledermaus / Spanish: Vespadela de Troughton

Other common names: Troughton’s Forest Bat, Troughton’s Vespadelus

Taxonomy. Eptesicus troughtoni Kitchener, B. Jones & Caputi, 1987,

“ Yarramulla Lava Tunnels, Mt Surprise, Queensland (18°13'30"S, 144°40°30"E), altitude 840 m,” Australia.

This species is monotypic.

Distribution. E Australia, in Queensland (including Magnetic I) and NE New South Wales.

Descriptive notes. Head-body 37-5-44. 2 mm, tail 314-379 mm, ear 10-4-12. 5 mm, forearm 30-36-4 mm; weight 4-5-6-7 g. Dorsal pelage is light brown (tips of hairs ginger, mainly around head), whereas ventral pelageis slightly lighter (darkbased hairs with light fawn tips). Bare portions of face, ears, and membranes are brown, and lips are apparently black. Ears are small and rounded triangular with a smoothly convex anterior edge; tragusis narrow, anteriorly straight orslightly concave, posteriorly convex, and with rounded tip and slight posterobasal lobe. Uropatagium reaches to tip of tail. Penis is pendulous and swollen distally; head of glans is laterally compressed with a deep furrow on ventral surface and blunttip; urethra is at the tip of the glans penis and is covered by narrow triangular strip ofskin projecting upward from ventral portion of opening. Baculum is moderately long (mean 3-7 mm), rodshaped dorsally, moderately bifurcated with wide base, and bow-shaped in lateral view (more bent at basal end). Skull is moderately long; lambdoidal crest is weakly to well developed; anterior narial notch is narrow U-shaped to V-shaped; rostrum is short. I? is bicuspid, I? is unicuspid; P* is much smaller than C', and within tooth row; crista linking base of metacone and hypocone on M' is absent, slight, or moderate, and absent, slight, or moderate on M>.

Habitat. Generally found close to sandstone or volcanic escarpments, and has been recorded in tropical mixed woodlands, wet and dry sclerophyll forest near coasts, and drier forests in more inland regions.

Food and Feeding. The Eastern Cave Bat forages by aerial-hawking. It seems to prefer foraging over water bodies rather than in vegetation, and has been observed foraging in small sections of creeks. One individual was observed remaining less than 10 cm above the surface while foraging; it flew back and forth over the creek along a 20m section and then frequently changed to new sections. The speciesis generally insectivorous, details of the diet are not well known;it has been seen feeding on mosquitoes.

Breeding. Eastern Cave Bats seem to reproduce once a year, births probably occurring from midto late November and possibly into December. Pregnant females were captured in October near Cooktown; lactating females were captured in early December on the Atherton Tableland and in January in Cape Melville, northern Queensland. In New South Wales, too, births occur in midto late November consistently. Litter size varies between one and two, although single young seem to be more common. Young remain attached to the female initially after birth, but are subsequently left alone at the roost in clustered groups of more than ten, while the females forage at dusk.

Activity patterns. The Eastern Cave Bat is nocturnal, leaving the roost at dusk to forage. Females with young have been reported to come back to the roost at least once during the night before going back outto forage. These bats have been recorded roosting in sandstone overhang caves, boulder piles, mines, and sometimes buildings. They have also been reported roosting in abandoned fairy martin (Petrochelidon ariel) nests; usually 2-3 bats can roost within,if it is unbroken. Eastern Cave Bats appear to roost near the entrances of their roosts in comparatively well-lit regions, often in small domes in the roofs of caves or in cracks or crevices. Call shape is FM/QCF with a characteristic frequency of ¢.50 kHz.

Movements, Home range and Social organization. The Eastern Cave Bat does not seem to travelfar to forage. A male was observed traveling within an area of only 33 ha over a span of five consecutive nights. Roost size varies from single individuals to a few hundred, with smaller colonies often being made up of a single sex, roosting tightly together in a small space. Females form maternity colonies with their young, with up to 240 adults recorded. There does not seem to be a major selective pressure for microclimate stability within roosts. Eastern Cave Bats seem to change roosts more often than other members of the genus, and females will shift roosts with their young every few days (up to 3-5 km to a new roost in one case).

Status and Conservation. Classified as Least Concern on The IUCN Red List. There are no major threats currently affecting the Eastern Cave Bat.

Bibliography. Churchill (2008), Ellis (2001), Ford & Le Brocque (2000), Kitchener et al. (1987), Law & Chidel (2007), Law, Chidel & Mong (2005), Law, Reinhold & Pennay (2002), Parnaby et al. (2008), Pennay & Hall (2008b), Schulz (1998a), Schulz & Oliveira (1995).