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Australian Long-fingered Bat (Miniopterus orianae)

The Australian Long-fingered Bat is a nocturnal, insect-eating, cave-roosting bat of south-eastern South Australia and western Victoria. It is listed as Critically Endangered under the EPBC Act, and development can affect the small network of maternity caves, non-breeding roosts, flight paths and wetland-associated foraging habitat on which the population depends.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

New South Wales, Biodiversity Conservation Act 2016: Vulnerable.

Victoria, Flora and Fauna Guarantee Act 1988: Critically endangered.

South Australia, National Parks and Wildlife Act 1972: Endangered.

Breeding season

Timing varies between the two maternity colonies and between years. The pattern below is a practical guide for south-eastern South Australia and western Victoria, not a substitute for site-specific survey and specialist advice.

A maternity cave, known non-breeding cave or occupied artificial roost should be managed as sensitive in every month until use has been assessed by a suitably qualified bat specialist.

  • Movement to maternity caves: Mating occurs in late autumn to early winter. Most bats begin migration around August, use transition caves, and complete the move by October.
  • Breeding and births: Births occur from mid-November to January. The Warrnambool colony may give birth later than Naracoorte, with births reported in early December there.
  • Dependent young: Young are dependent during the maternity period, become fully furred and able to fly after about 4 to 5 weeks, and are generally weaned and independent by February to March.
  • Dispersal and winter roosting: Most adults disperse to non-breeding caves from February to March. From April to August, bats are dispersed among cool overwintering caves and use torpor when insect food is scarce.
  • Highest clearing risk: Disturbance is most likely to harm the species during births and dependent young from November to March, and during winter torpor from April to August. Migration and transition-cave use from August to October also require protection of roosts and flight routes.

Identification

This is a medium-sized, fast-flying bent-wing bat with dark brown fur and a distinctive elongated third finger. Identification in the field is difficult where it overlaps with other Miniopterus taxa, particularly the Eastern Bent-wing Bat in western Victoria.

The back is dark reddish-brown to dark brown, while the underparts are grey-brown. Bare skin is pale brown. The head is high crowned or domed, the muzzle is short, the eyes are small, and the ears are short, rounded and roughly triangular.

The last phalanx of the third wing finger is about four times the length of the middle phalanx. This produces the bent-wing appearance when the bat is at rest. The wing membranes attach to the ankles.

Head and body: 52 to 58 mm

Forearm: 45 to 49 mm

Mean weight: 15.7 g

Wingspan: Approximately 30 to 35 cm

Identification: Distinguishing similar bats

Miniopterus orianae taxa are morphologically similar. The Southern Bent-wing Bat overlaps with the Eastern Bent-wing Bat in western Victoria, and the two cannot be reliably separated using traditional field characters. They also roost together in some caves.

Do not assign a southern or eastern subspecies from photographs, body colour or the bent wing alone. Record the location, roost context and other observations, and obtain advice from a bat specialist where taxon-level identification affects approvals or management.

Identification: Field signs and detection

The species is most likely to be detected by bats emerging from caves or other dark roost spaces around sunset, by acoustic survey, or by inspection of suitable roosts by a suitably qualified person.

Guano, staining and bat flies around joints, crevices, culverts and other enclosed structures are useful indicators of microbat use. These signs are not diagnostic of the Southern Bent-wing Bat and should be followed by specialist assessment and, where required, acoustic or other targeted survey.

There are no species-specific descriptions in the supplied documents for tracks, nests, eyeshine or a diagnostic echolocation call. Do not rely on these features for identification.

Distribution: Range and strongholds

The Southern Bent-wing Bat occupies a restricted part of south-eastern Australia. The population is centred on two maternity caves separated by approximately 220 km, with a wider network of seasonal roosts and feeding areas between south-eastern South Australia and western Victoria.

In South Australia, the core range extends from around Robe and Naracoorte south to Port MacDonnell, and north to Marcollat. The population is centred on Naracoorte Bat Cave in Naracoorte Caves National Park.

In Victoria, records extend from the western coastal and hinterland areas around Warrnambool and Portland to Hamilton, Pomborneit and Lorne. The regularly used Victorian maternity cave is near Warrnambool on a sea cliff on private land.

The two regularly used maternity sites are Naracoorte Bat Cave in South Australia and the Warrnambool maternity cave in Victoria. Non-breeding caves include 48 known sites in South Australia and several in Victoria.

South Australian range: Around Robe, Naracoorte, Port MacDonnell and Marcollat, with additional historical or outlying records.

Victorian range: Western Victoria, including Warrnambool, Portland, Hamilton, Pomborneit and Lorne.

Known regularly used maternity sites: Two.

Known South Australian non-breeding caves: 48.

  • Treat records outside the core range, including historical records from the Flinders Ranges, Mount Lofty, Port Adelaide and Yorke Peninsula, as requiring verification because some are old or difficult to confirm.
  • The species has also been recorded around Heywood, Portland and Hamilton in western Victoria.

Distribution: Population size and trend

The population declined substantially over the late twentieth and early twenty-first centuries. Estimates are affected by changing survey methods and by the fact that not all bats are present at the two maternity caves during every count.

The consultation assessment estimated a total population of approximately 41,000 individuals from the two maternity colonies. It estimated a decline of around 75 percent from approximately 165,000 to approximately 41,000 over the three-generation assessment period from 1983 to 2019.

Estimated total population: Approximately 41,000 individuals, based on the consultation assessment.

Estimated mature individuals: Approximately 27,000 in the consultation assessment.

Estimated decline: Around 75 percent over approximately 30 to 36 years, based on the consultation assessment.

Naracoorte estimate: 25,000 to 37,000 individuals in 2011 to 2012.

Warrnambool estimate: Approximately 10,000 individuals in 2004, with further monitoring required.

Habitat: Foraging and movement habitat

Habitat use is determined by the combination of suitable cave or tunnel roosts, seasonal microclimates and productive insect-feeding areas. The species may travel widely between these habitat components, so a cleared work area can be relevant even when no roost is present on the site.

Foraging habitat includes forested areas, woodlands, volcanic plains, wetlands, swamps, river basins, coastal vegetation and, in some areas, urban areas. Forested ridgelines and wetlands are commonly used, while open pasture and radiata pine plantations are used less frequently.

Primary habitat is associated with woodlands near large natural wetlands, river basins and agricultural areas. Important feeding areas and movement corridors remain incompletely defined.

  • Inspect wetlands, swamps, waterways, forest edges, remnant woodland and open flight corridors when assessing a project near a known roost.
  • Retain native vegetation and wetland margins where practicable, particularly around known maternity and non-breeding caves.

Habitat: Roost habitat and climate

The species is an obligate cave-dweller but can use limestone caves, lava tunnels, coastal cliff crevices, mines and man-made tunnels. Different roosts are selected at different times of year according to temperature and humidity.

Maternity caves have structural features that allow heat and humidity to build up. Naracoorte Bat Cave has reported relative humidity of about 80 percent and a breeding area at around 30 degrees Celsius, approximately 10 degrees Celsius warmer than the rest of the cave.

Naracoorte maternity microclimate: About 80 percent relative humidity and around 30 degrees Celsius in the breeding area.

Known winter roost network: More than 50 caves are known to be used as overwintering sites, including the 48 known South Australian non-breeding caves and sites in Victoria.

  • Assess caves, mines, tunnels, culverts, cliff crevices and other enclosed structures within the project area and along likely flight routes.
  • Include the cave entrance, internal microclimate, surface above thin cave roofs and access routes in the impact assessment.

Foraging habitat: Diet and feeding method

The Australian Long-fingered Bat catches insects in flight using echolocation. It generally hunts in open airspace above or beside vegetation and may travel many kilometres from its roost.

The diet includes moths, flies such as mosquitoes and midges, crickets, beetles, bugs, ants and other night-flying insects. Moths appear to be particularly important, as moth wings are frequently found near cave entrances.

The bat is nocturnal and uses ultrasonic echolocation for navigation and feeding. Prey is caught in flight, often in the tail or wing membrane, and transferred to the mouth while flying.

Main prey: Moths and other night-flying insects.

Other recorded prey groups: Diptera, Orthoptera, Coleoptera, Hemiptera and Hymenoptera.

Foraging habitat: Foraging areas and range

The species forages above forest canopies, along forest clearings, over wetlands and swamps, and across open country. It usually has a fast, direct flight pattern and uses open airspace rather than dense understorey.

Individuals can travel up to 35 km from a roost to feed. Older guidance reports that distances may increase to about 30 km where roosts are in suboptimal feeding habitat.

Maximum reported foraging distance from a roost: Up to 35 km.

Typical flight height near trees: Above the canopy.

Typical flight in open country: About 6 m above the ground in the cited field account.

  • Map wetlands, swamps, waterways, forested ridgelines, remnant woodland and open flight paths between roosts and feeding areas.
  • Assess lighting, tall structures, wind turbines, clearing and changes to water availability where works occur near known roosts.

Breeding habitat: Breeding biology

Breeding is concentrated in two regularly used maternity caves. These sites provide a warm, humid microclimate and are highly sensitive to disturbance, physical damage and changes to the cave entrance or roof.

Mating occurs from late autumn to early winter. In August, most of the population migrates from non-breeding roosts to a maternity cave, using transition caves during the journey.

Females give birth to a single young from mid-November to January. Young develop rapidly, become independent by February to March and then most adults disperse to non-breeding caves.

Mating: Late autumn to early winter.

Migration to maternity caves: Begins around August and is generally complete by October.

Litter size: One young per female.

Birth period: Mid-November to January.

Gestation: Approximately 6 to 7 months.

Age at sexual maturity: Around 2 years.

Lifespan: Up to 22 years.

Breeding habitat: Maternity cave requirements

Naracoorte Bat Cave and the Warrnambool maternity cave are the only two regularly used maternity sites identified in the supplied documents. Their internal structure allows heat and humidity to build up for nursing young.

Young can be dislodged by disturbance and are unlikely to survive if they fall from the cave ceiling. Noise, lights, entry, vibration or physical changes near a maternity cave can therefore affect breeding success even when the work footprint is outside the cave.

  • Protect both maternity caves and their entrances from direct disturbance, vibration, altered drainage, roof loading and changes to airflow.
  • Manage access and construction timing through a bat specialist and the relevant land manager or regulator.

Sheltering habitat: Seasonal roosts

The species uses a seasonal network of caves and other enclosed roosts. Maternity colonies are concentrated and large, while non-breeding bats may occur in smaller groups or singly.

Limestone caves are the main roosts. Lava tunnels, coastal cliff rock crevices, disused mines and man-made tunnels may also be used. In some areas, tunnels, road culverts and similar structures provide roosting habitat.

During winter, bats select the coolest parts of cool caves and enter deep torpor. Their body temperature can fall to about 2 degrees Celsius. Repeated disturbance during this period uses stored body fat and can reduce survival.

Winter body temperature in deep torpor: Can fall to about 2 degrees Celsius.

Roost colony size: Non-breeding colonies are considerably smaller than maternity colonies, and individuals may roost singly.

  • Inspect dark, sheltered cavities, culverts, tunnels, mines, cave entrances and coastal rock crevices before works.
  • Treat guano, staining, bat flies and repeated bat emergence as evidence of possible roost use, not as proof of species identity.

Sheltering habitat: Artificial structures and surface features

Bent-wing bats can roost in transport structures, including enclosed joints, culvert spaces, scuppers and gaps in bridge decking. They do not generally breed in these structures, but they may use them as part of the seasonal roost network.

The surface above the Warrnambool maternity cave is thin and may be damaged by heavy agricultural machinery. Natural coastal collapse has also affected cave habitat.

  • Before sealing, demolishing, relining or modifying a culvert, bridge, tunnel or mine, engage a microbat specialist to inspect the structure and prepare a management plan where required.
  • Keep machinery, vibration and heavy loads away from thin cave roofs and known underground voids.

Threats: Clearing, fragmentation and hydrology

The main risks are loss or damage to maternity and non-breeding roosts, disturbance during breeding or torpor, loss of wetland and woodland feeding habitat, disease and infrastructure-related mortality. Because most of the population is associated with two maternity caves, an impact at one site can affect a large proportion of the taxon.

Historic clearing has removed about 90 percent of native vegetation across the subspecies' range. Further clearing, fragmentation, removal of linear vegetation and agricultural intensification can reduce feeding habitat and movement routes.

Drainage or loss of wetlands, groundwater over-extraction, drought and altered river systems can reduce insect prey and water availability. Drying of important wetlands may reduce breeding success and adult survival.

  • Avoid clearing native woodland, forest edges, wetland margins, swamps and waterways near known roosts where practicable.
  • Assess changes to surface water, groundwater, wetland inundation and drainage as potential bat impacts, not only as vegetation impacts.

Threats: Roost damage and disturbance

Guano mining, rubbish dumping, cave closure, inappropriate gates, cave entrance changes and natural collapse have caused the loss or abandonment of roosts. The Warrnambool maternity cave is exposed to roof collapse and coastal weathering.

Noise, lights, vibration, handling and human entry can cause maternity disturbance or arousal from torpor. Repeated disturbance may lead to cave abandonment, which can cause mortality rather than simple movement to another cave.

  • Do not enter or modify a suspected roost without specialist advice and approval from the relevant land manager or regulator.
  • Control lighting, vibration, blasting, drilling, vehicle access and worker entry near roosts, with stricter controls during maternity and winter torpor periods.

Threats: Disease, predators and infrastructure

Disease has caused documented mortality, including a historical viral event at Naracoorte and later pup mortality and skin lesions. White-nose Syndrome has not been recorded in Australia, but risk assessments identify cave-roosting bats as highly vulnerable if it is introduced.

Foxes, feral cats and black rats may take bats at cave entrances. Barb wire in flight paths can cause mortality. Wind farms near roosts or migration routes may cause collision, barotrauma, cave impacts and loss of access to feeding areas.

  • Prevent unauthorised handling of bats and use trained, vaccinated personnel for any required handling because Australian Bat Lyssavirus exposure can occur through bites or scratches.
  • Remove or modify barb wire in known flight paths where practicable, and assess turbines in relation to maternity caves, non-breeding caves, feeding areas and seasonal movement routes.
  • Include predator activity and disease biosecurity in roost management, particularly at maternity cave entrances and during colony emergence.

Survey methodology: 1. Review records and map habitat

Survey this taxon as a cave-roosting bat that moves between maternity caves, non-breeding caves and foraging areas. Survey design must account for seasonal movement, difficult field identification where it overlaps with the Eastern Bent-wing Bat, and the possibility that individuals use structures away from caves.

Before field work, obtain current records and map caves, mines, tunnels, culverts, cliff crevices, wetlands, forested ridgelines, waterways and other potential foraging areas.

Give particular attention to the two regularly used maternity caves, Naracoorte Bat Cave in South Australia and the Warrnambool maternity cave in Victoria, and to known non-breeding caves. The species may travel up to 35 km from a roost to forage.

Treat all populations and all roost sites as important because the taxon has declined severely and depends on a small number of maternity sites.

Core range: South-eastern South Australia to south-western Victoria

Regularly used maternity sites: Two, Naracoorte Bat Cave and a cave near Warrnambool

Known South Australian non-breeding caves: 48

Potential foraging distance from roost: Up to 35 km

  • Search state wildlife databases, museum records, local cave managers and the current recovery plan before finalising the survey area.
  • Use the Australian Government threatened bat survey guideline and any current state survey guideline when setting the method and effort.
  • Do not assume that a lack of records means that the species is absent from suitable habitat.

Survey methodology: 2. Cave exit counts and thermal imaging

Use non-intrusive exit counts at known or suspected maternity caves where access and approvals allow. Video recording and automated thermal imaging have both been used to count bats leaving Naracoorte Bat Cave.

At Naracoorte, earlier surveys used counts on one to three occasions per summer, while a later automated system recorded exits several times a week during the 2011 to 2012 breeding season. Use repeated counts where population estimation is required, rather than relying on one count.

Record the date, start and finish time, weather, temperature, wind, rainfall, cave condition, equipment used and whether the count captured the full emergence.

Historical Naracoorte estimate from video counts: 20,000 bats in 2008 to 2009

Later Naracoorte thermal imaging counts: 25,000 to 37,000 bats during the 2011 to 2012 breeding season

Recommended survey period for maternity counts: The breeding season, when most individuals congregate at maternity caves

  • Position equipment so that it does not block the flight path or disturb the colony.
  • Use thermal imaging or video where practicable, because mark and recapture can cause disturbance and has high uncertainty.
  • Confirm that most bats have exited before treating an exit count as complete, if this can be done without entering or disturbing the cave.
  • Do not enter a maternity cave during a count unless the approved method specifically requires it and the work is authorised.

Survey methodology: 3. Acoustic and activity surveys

Use ultrasonic acoustic detectors to identify bat activity along likely flight paths, at cave entrances, around culverts and tunnels, and over wetlands, waterways, forested ridgelines and other open foraging areas.

Acoustic results should be interpreted by a suitably experienced bat ecologist. The Southern Bent-wing Bat and Eastern Bent-wing Bat overlap in western Victoria and cannot always be reliably separated using traditional field methods.

Deploy detectors across the relevant seasonal period and include repeated nights where the project could affect a roost, flight path or key foraging area. The supplied documents do not prescribe a universal number of detector nights or hours for this taxon, so use the current threatened bat survey guideline and state requirements to set effort.

Typical activity period: Nocturnal

Foraging flight pattern: Fast and direct, commonly above the canopy or in open space

Known foraging distance: Up to 35 km from a roost

  • Record detector make, settings, deployment location, deployment dates, operating hours, weather and file review method.
  • Place detectors between roosts and likely foraging habitat, not only at the project footprint, where a flight path could be affected.
  • Combine acoustic records with habitat inspection and, where appropriate, exit counts or targeted cave surveys.
  • Do not use a single unidentified bat call as confirmation of this taxon where the Eastern Bent-wing Bat may also occur.

Survey methodology: 4. Roost and structure inspections

Inspect caves, mines, tunnels, culverts, bridges and coastal cliff crevices for roosting bats, guano, staining, bat flies, entry and exit points, and suitable temperature and humidity conditions.

Bent-winged bats may roost in transport structures but do not give birth there. They use a network of roosts and may change roosts regularly.

Survey during the season relevant to the proposed disturbance. Bats use different caves during breeding and winter, and wintering bats are highly susceptible to disturbance because they are in torpor.

Breeding migration: Most individuals move to maternity caves from around August

Birth period: Mid-November to January

Young independent: February to March

Winter torpor period: Cooler months, with winter dispersal from April to August described for the southern population

  • Use an experienced microbat specialist for confined-space, cave or structure inspections.
  • Do not enter a confined space without the required confined-space controls, approvals and specialist capability.
  • Inspect for bats before works and immediately before disturbance if the structure could be occupied.
  • Treat a cave or structure as occupied until a suitably qualified person confirms otherwise using an appropriate method.

Survey methodology: Minimum effort and reporting

  • Use the current Survey Guidelines for Australia's Threatened Bats and relevant state guidance to document the required number of nights, detector hours, transects, inspection effort and seasonal coverage for the project.
  • State the survey dates, start and finish times, weather, wind, rainfall, temperature, equipment, detector settings, observers, search areas and limitations.
  • Report all confirmed records, roosts, maternity caves, non-breeding caves, flight paths and important foraging areas to the relevant state wildlife database and the project approval authority.
  • Submit records to the Australian Government where required for an EPBC Act matter and retain the original acoustic, thermal and video files.
  • Record the taxonomic basis for identification and flag records that may be confused with the Eastern Bent-wing Bat.

Before habitat disturbance: 1. Avoid and minimise habitat loss

Avoid disturbance to caves, roosts, flight paths and foraging habitat before considering mitigation. This taxon is concentrated at a small number of maternity caves, so damage or disturbance at one site can affect a large part of the population.

Retain known maternity caves, non-breeding roosts, transition caves, cave entrances, tunnels, culverts and coastal cliff crevices.

Retain wetlands, swamps, waterways, forested ridgelines, woodland, riparian vegetation and other open foraging habitat connected to roosts.

Protect the Warrnambool maternity cave from loading, storage, vehicle access and heavy machinery above the thin cave roof. Natural coastal collapse and storm damage are also identified risks.

Avoid clearing or modifying habitat around maternity roosts and key non-breeding roosts. The key foraging areas for this taxon are not fully defined, so use a precautionary approach.

Known maternity caves: Two regularly used sites

Important foraging habitats: Forested ridgelines, wetlands, waterways, woodlands and open spaces

Recorded foraging distance: Up to 35 km from a roost

  • Redesign the project footprint to retain roosts and connected flight paths wherever practicable.
  • Do not place wind turbines or other tall infrastructure near roosts or along important movement paths without a specific bat risk assessment.
  • Keep artificial lighting, noise and human access away from cave entrances and roost structures.
  • Avoid barb wire fencing across flight paths to and from roosts.

Before habitat disturbance: 2. Check approvals and prepare the plan

The taxon is listed as Critically Endangered under the EPBC Act as Miniopterus orianae bassanii. Refer a proposed action if it may have a significant impact on the species or its habitat.

Check state threatened species legislation, wildlife licences, cave access permissions, landholder permissions and any conditions attached to existing approvals.

Prepare a fauna management plan where works may affect a roost, cave, tunnel, culvert, wetland, flight path or foraging area.

Include a qualified bat ecologist, fauna spotter catcher, site supervisor, machinery operators and an escalation contact in the plan.

Commonwealth status: Critically Endangered under the EPBC Act

Recovery planning status: A National Recovery Plan is in effect under the EPBC Act

Current threats relevant to planning: Roost damage, foraging habitat loss, disease, climate change, human disturbance, predators, fencing, windfarms, fire and toxins

  • Define no-go areas, exclusion zones, access routes, lighting controls, work hours, stop-work triggers and notification procedures.
  • Schedule noisy, lit or intrusive work outside breeding and winter torpor periods where the risk assessment identifies that this is practicable.
  • Stage works so that retained habitat remains connected and bats are not forced into marginal roosts.
  • Include an emergency response for cave collapse, injured bats, unexpected roost discovery, fire, flooding and equipment failure.

Before habitat disturbance: 3. Pre-clearance and site controls

Complete a pre-clearance inspection immediately before works, including caves, mines, tunnels, culverts, bridges, cliff crevices, wetlands and any structure that could provide roost habitat.

Mark maternity caves, non-breeding roosts, cave entrances, flight paths, wetlands, retained vegetation and other habitat features on plans and on the ground.

Use exclusion fencing or other physical controls where they can protect habitat without blocking bat flight or access to a roost.

Brief all workers that bats may be present in dark gaps, culverts, bridge joints, tunnels and caves, and that workers must not handle them.

  • Install fencing outside the flight path and well clear of cave entrances, access points and wetland edges.
  • Check that temporary fencing, shade cloth, sediment controls and lighting do not obstruct bat movement.
  • Inspect all structures for guano, staining, bat flies, live bats and entry points before sealing, dismantling or filling them.
  • Keep a qualified ecologist available during the first disturbance of each potentially occupied feature.

During habitat disturbance: 1. Daily controls and machinery interface

Use daily controls because bats can occupy roosts that were not detected during the initial survey. Work must stop when an occupied roost, injured bat, maternity colony or unexpected habitat feature is found.

The fauna spotter catcher must inspect the work area and nearby roost features before each shift and after any change in the work method.

The spotter catcher must remain in direct communication with the machinery operator and site supervisor and must be able to stop work immediately.

Keep machinery, vehicles, lighting and personnel outside marked exclusion zones unless the approved fauna management plan allows entry.

Use low-intensity, directed lighting and avoid lighting cave entrances, roost openings and known flight paths.

  • Use one agreed stop-work signal and test it at the daily pre-start meeting.
  • Move machinery slowly when approaching marked habitat and keep the bucket, blade or attachment under the spotter catcher’s direction.
  • Do not seal, fill, demolish, gate, clean or modify a cave, culvert, tunnel or bridge joint until it has been checked for bats.
  • Do not work over the Warrnambool maternity cave or other thin-roofed cave where machinery could cause collapse.
  • Keep workers out of caves and confined structures unless the work is authorised and the required specialist and confined-space controls are in place.

During habitat disturbance: 2. Habitat features and unexpected finds

Treat caves, mines, tunnels, culverts, bridge gaps, coastal crevices and dark structural joints as potential roost features even when no bat is visible.

Retain wetlands, waterways, logs, rocks, woody debris and vegetation that connect roosts with foraging areas where these features are within the approved retention area.

For this cave-roosting species, hollow-bearing trees, logs and rocks are not substitutes for maternity caves. Do not describe them as maternity habitat unless field evidence supports that conclusion.

If clearing exposes a new cave, tunnel, mine opening, culvert roost or wetland, stop work in the affected area and obtain an assessment by a bat ecologist.

  • Do not move rocks, logs or woody debris near a roost without checking for bats and obtaining approval under the fauna management plan.
  • Do not drain, fill or isolate wetlands and swamps used as foraging habitat without implementing the approved impact controls.
  • Do not remove weed growth around a cave entrance during the breeding or winter period unless the work has been assessed and authorised.
  • Do not install gates over cave entrances without specialist design and approval, because bent-wing bats may not tolerate them.

During habitat disturbance: 3. Bat handling, relocation and stop-work response

If a bat is found, stop work in the immediate area, keep people and machinery back, and contact the fauna ecologist or authorised fauna spotter catcher.

Do not handle a bat unless the person is trained, appropriately vaccinated against Australian Bat Lyssavirus and authorised under the applicable state requirements.

A bat found in a structure should be relocated only under the approved fauna management plan and by an appropriately qualified person, to nearby retained habitat that provides suitable shelter and does not block the animal’s normal movement.

Take injured or grounded bats to a veterinarian or licensed wildlife carer through the approved wildlife rescue pathway.

Australian Bat Lyssavirus exposure response: Wash a bite or scratch for at least five minutes and seek medical advice within 12 hours

Handling requirement: Current lyssavirus or rabies vaccination, experience and training, and relevant authorisation

  • Do not touch, chase, shine high-powered lights at or repeatedly disturb roosting bats.
  • Stop work for any live bat in the disturbance zone, an injured or dead bat, a maternity colony, repeated bat activity, a newly discovered roost, cave damage or a collapse risk.
  • Isolate the area until the ecologist confirms the controls, relocation decision and restart conditions.
  • If a worker is bitten or scratched, wash the wound thoroughly for at least five minutes and seek medical advice within 12 hours.
  • Record the location, time, species or identification confidence, condition, action taken, handler, destination and photographs where this can be done safely.

After habitat disturbance: 1. Post-clearance inspection

Post-work controls must confirm that no roost, flight path or foraging area has been left damaged or isolated. Monitoring should be scaled to the risk and continue where the project affects a known roost or important habitat.

The fauna ecologist must inspect the cleared area, retained habitat, access routes, structures and exclusion zones after each work stage.

Check for injured or grounded bats, exposed cave openings, damaged roost structures, blocked entrances, new lighting, changed drainage and barriers across flight paths.

Inspect culverts, bridge joints, tunnels and other structures again after demolition, lifting, cleaning, sealing or modification.

Remove temporary controls only after the ecologist and site supervisor confirm that the area is safe and that retained habitat remains protected.

  • Complete a final walkover at the end of each clearing stage and after heavy machinery leaves the site.
  • Check nearby wetlands and waterways for sediment, altered water levels, pollution and loss of insect-producing habitat.
  • Photograph and map all damage, retained habitat, exclusion zones and reinstatement works.
  • Keep access to retained caves and roost structures controlled after construction.

After habitat disturbance: 2. Monitoring and reporting

Monitor known or potentially affected roosts and foraging areas using the approved method, which may include acoustic detectors, video exit counts or thermal imaging.

Use repeated monitoring where a project could affect a maternity cave, a significant non-breeding cave, a flight path or a key wetland.

Compare results with the pre-work baseline and investigate changes in activity, emergence numbers, roost use, habitat condition or mortality.

Report any impact, unexpected mortality, cave damage, new roost record or failure of a mitigation measure to the approval authority.

Historical population trend: The Southern Bent-wing Bat population was estimated to have declined by about 75 percent over 1983 to 2019

Population concentration: Most individuals congregate at the two maternity caves during the breeding season

  • Continue monitoring for the period specified in the EPBC approval, state approval or fauna management plan.
  • Submit confirmed records and updated spatial data to the relevant state wildlife database.
  • Provide the land manager and approval authority with survey data, incidents, corrective actions and monitoring results.
  • Review the controls if bats abandon a roost, use a new structure, suffer mortality or show reduced activity.

After habitat disturbance: 3. Offsets and corrective action

Apply any approved offset, biodiversity credit, compensation or restoration requirement specified under Commonwealth or state legislation.

Do not use an offset as a substitute for avoiding damage to a maternity cave or occupied roost.

Where monitoring identifies an impact, implement corrective action such as removing lighting, restoring wetland water regimes, reopening a blocked flight path, controlling predators or modifying the work area.

Document the action, responsible person, completion date and evidence that the risk has been reduced.

  • Escalate an impact to the project environmental officer and approval authority within the timeframe required by the approval.
  • Update the fauna management plan when a new threat or roost is identified.
  • Keep all records for the period required by the approval and make them available to future site managers.

Rehabilitation actions: 1. Restore foraging habitat and connectivity

Rehabilitation should restore the roost to foraging connection rather than treating revegetation alone as sufficient. The two maternity caves, suitable non-breeding roosts and productive wetlands are the main habitat priorities for this taxon.

Re-establish native woodland, forest, wetland-edge and riparian vegetation around retained roosts, wetlands, waterways and forested ridgelines.

Use locally appropriate native plants suited to the original community and site hydrology. The supplied documents do not nominate a fixed planting list for this taxon.

Restore wetland and swamp water regimes where construction has altered drainage, while preventing sediment, chemical contamination and excessive weed growth.

Maintain open flight space at cave entrances and along known movement routes; do not plant or fence across the entrance or flight path.

Common foraging habitat: Forested ridgelines and wetlands, with open pasture and Radiata Pine plantations used less often

Foraging distance: Up to 35 km from a roost

Historical habitat loss: About 90 percent of native vegetation in the subspecies range was reported as cleared

  • Prioritise links between roosts and wetlands, waterways, forested ridgelines and other insect-producing habitats.
  • Use staged planting where immediate works could block bat movement or access to a roost.
  • Control weeds around cave entrances and structures without narrowing the flight opening or disturbing roosting bats.
  • Prevent new lighting from being directed at restored roost entrances or flight paths.

Rehabilitation actions: 2. Retain and improve roost structures

Protect existing caves, mines, tunnels, culverts, coastal crevices and suitable bridge structures from sealing, collapse, inappropriate gates and repeated human access.

Reinstate a removed or damaged roost structure only where a bat ecologist confirms that the design, microclimate, access and location are suitable for this taxon.

Do not assume that nest boxes, tree hollows, logs or rocks will replace a maternity cave. The species requires specific cave microclimates for breeding.

Manage disused mines and artificial caves for bat conservation values after assessing occupancy, human interference, ownership and safety.

Naracoorte maternity cave conditions: About 80 percent relative humidity and about 30 degrees Celsius in the breeding chamber

Roost types recorded: Limestone caves, lava tunnels, coastal cliff crevices and man-made tunnels

  • Retain the entrance dimensions, airflow, humidity and temperature characteristics of an occupied roost where works affect a cave or tunnel.
  • Keep restored entrances free of fencing, stored materials, weeds, sediment and artificial light.
  • Use specialist advice before installing any gate, grille or exclusion device because bent-wing bats may abandon unsuitable gated caves.
  • Do not enter or clean a restored roost during breeding or winter torpor periods unless the approved management method requires it.

Rehabilitation actions: 3. Control predators, weeds, fire and toxins

Control feral cats, foxes and black rats around maternity and other important roosts under an approved pest management programme.

Inspect cave entrances and nearby habitat for predator access, fox scats, cat activity and rat activity after rehabilitation works.

Manage fire risk so that smoke is not drawn into caves and so that severe fire does not remove key foraging habitat or reduce insect prey.

Prevent pesticide and other toxin contamination of wetlands, waterways and foraging habitat.

Predators recorded or suspected: Feral cats, foxes, black rats and some native predators

Toxins recorded: DDT, DDE and other pesticide residues have been found in bats and guano

  • Use non-toxic or approval-compliant weed and pest control methods near roosts and wetlands.
  • Keep construction chemicals, fuels and sediment out of cave entrances, wetlands and waterways.
  • Coordinate fire planning with the land manager and avoid activities that increase smoke entry into occupied caves.
  • Record predator control, weed treatment, fire events, chemical incidents and corrective actions.

Rehabilitation actions: 4. Monitor rehabilitation success

Monitor restored roosts, cave entrances, wetlands, vegetation, weeds, predators, lighting and bat activity for the period required by the approval or recovery plan.

Use acoustic monitoring, thermal imaging or video exit counts where these methods are suitable and approved for the site.

Measure whether roost access remains open, wetland hydrology is functioning, native vegetation is establishing, flight paths remain unobstructed and predator pressure is controlled.

Treat the rehabilitation as unsuccessful if bats are excluded from a retained roost, a roost is abandoned because of the works, mortality occurs, or key foraging habitat continues to deteriorate.

Recommended monitoring focus: Roost use, emergence activity, flight paths, wetland condition, vegetation establishment, weeds, predators and mortality

Breeding period to protect during monitoring: Mid-November to January for births, with young independent by February to March

  • Set site-specific success measures before works begin and record the baseline condition.
  • Inspect restored features after storms, floods, fire, heavy machinery access and major maintenance events.
  • Continue management until the agreed success measures are met, not only until planting is completed.
  • Submit monitoring outcomes and new records to the relevant state wildlife database and approval authority.

Sources