Miniopterus australis
little long-fingered bat

Miniopterus australis inhabits the subtropical coastal regions of Indonesia, Philippines, New Guinea, and Australia. In Australia, its range does not exceed the north-eastern coast. Miniopterus australis has a southern range limit in north-eastern New South Wales with a latitude of 31°15' S. The southern limit may be due to the close relationship M. australis has with Miniopterus schreibersii (common bent-wing bat). (Dwyer, 1968; Dwyer, 1983; Kithener and Suyanto, 2002)

Most M. australis roost in caves, but it is also known to roost in abandoned mines, tunnels, water drains, buildings, and tree hollows. The nursery sites are usually located in limestone caves. They appear to forage in environments at the edges of forests. (Dwyer, 1968; Rhodes and Hall, 1997; Schulz, 1997)

It appears that M. australis is reproductively dependent on M. schreibersii for warmth in these caves. Miniopterus schreibersii is almost twice the size of M. australis, and heat the cave nicely for the young of both species. This could be why the range of M. australis is concurrent with the southern range of M. schreibersii. Miniopterus australis does not migrate to a winter roost. (Dwyer, 1968; Schulz, 1997)

Miniopterus australis lacks a nose leaf. It appears grayish-black, but changes color during the year to a fawnish-brown. A closer look reveals a coat with pale brown under-fur topped with a chocolate brown color. Both males and females molt. However, females tend to molt later than males because they may be lactating during the normal time of molting. (Dwyer, 1968; Dwyer, 1983)

Miniopterus australis is closely related to and looks much like M. schreibersii, but is slightly smaller. It weighs 7 to 8 g and has a total length of 86 to 96 mm. Males and females do not exhibit any type of dimorphism; they are relatively the same size and weight, except for pregnant females who will gain 2 to 3 g. The tail is just as long as the head and body together (43 to 48 mm), and the haired patagium covers most of the tail. The forearm of this species is a total of 36 to 40 mm long. (Dwyer, 1968; Dwyer, 1983)

The oldest recorded age of M. australis is five and a half years. This is based on an individual that was captured, marked, and recaptured. It is quite possible that they do live longer, but it has never been recorded. (Dwyer, 1968; Dwyer, 1983)

Miniopterus australis is a nocturnal animal, found living in colonies. A study done on ultrasonic detection of M. australis revealed that these bats fly in open areas as well as in forested areas. This is an indication that M. australis reside in edge habitats. It has been recorded flying up to 59.5 kilometers from the nursery site, but no more than that. In essence, this species tend to stay in the locality of their nursery roost.

Miniopterus australis is most active in spring, summer, and fall (mid-September to February and March to May). During the late winter months (July and August), M. australis enters torpor. There were only two events where clusters of this species appeared sluggish in the fall.

Dwyer (1968) found that active M. australis would leave their roost when disturbed by a human observer. Sluggish bats would leave the roost after ten minutes up on entrance of an observer, and torpid bats remained inactive even a half hour after entrance of an observer.

Miniopterus australis starts to colonize a nursery site in early spring, anywhere from August to September. At that time, the colony consists of adult males and females. Around October and November, most males leave the colony, which will then consist of females, their young, and a few males. The females start to leave their young in February and March. The young leave in April, and the roost is considered abandoned until the following August. Miniopterus australis does colonize in the same roost as M. schreibersii. Juveniles, who are not counted in surveys, may also be located in the nursery site, but will roost in other locations as well. (Dwyer, 1968; Rhodes and Hall, 1997)

Home Range

The home range of M. australis does not exceed 59.5 km from the nursery site. (Dwyer, 1968)

Miniopterus australis is an echolocator. These animals use high pitch frequencies to locate their prey and avoid obstacles while flying. Because they are an edge habitat species, they use a mix of FM and CF calls. (Jones and Corben, 1993)

As mammals, it is likely that they use some visual cues to communicate, as well as scent (especially the mother locating her young in the nursury cave). Tactile communication undoubtedly takes place in the somewhat crowded caves, as well as between mothers and their offspring and mates. (Nowak, 1999)

Miniopterus australis emerge in the evening to forage. Using echolocation, they fly between shrub and canopy layers of extremely wooded areas and prey on the small bugs under the canopy. (Dwyer, 1968; Dwyer, 1983)

As individuals of M. australis fly from their shelters, they will sometimes be snatched by pythons or ghost bats (one of the predatory bat species). Other common predators are owls and foxes. Many young may fall to the floor of the nursery roost and be overtaken by beetles that inhabit the area. (Dwyer, 1983)

The most information that was found on the ecosystem roles of M. australis is that they are predators of small bugs. They probably havve some effect on local insect populations. To the extent that they and are also prey for pythons, owls, ghost bats, foxes, and beetles, they may help provide nourishment for those predatory species.

There was no information found on negative impact of M. australis.

Miniopterus australis is insectivorous, and likely consumes insect pests.

Miniopterus australis is abundant in Indonesia, New Guinea, and the northeastern coast of Australia. Because they are not a threatened or endangered species, there are no attempts to legally protect them. There is no special status for M. australis on either the IUCN or CITES lists. (Dwyer, 1983)