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Northern Mastiff Bat (Chaerephon jobensis)

The Northern Mastiff Bat, Chaerephon jobensis, is a fast flying insectivorous microbat of northern Australia. It occurs in the Northern Territory, Queensland and Western Australia, and may roost in tree hollows, loose bark, rock fissures, caves, poles and buildings. It is listed as least concern in Australia, but roosts and breeding places still need careful treatment during clearing and construction, particularly in Queensland where colonial breeders require a high risk species management program.

Conservation status

Queensland, Nature Conservation Act 1992: Colonial breeder. Least concern in Queensland, but it breeds in colonies, so tampering with a breeding place needs a high risk species management program rather than the low risk program.

Breeding season

The Northern Mastiff Bat is poorly known in Australia, but microbats generally breed in the warmer months, from spring to late summer. Timing can vary between tropical and subtropical areas and between years, so confirm local roost use before clearing or construction.

Breeding mode: Live-bearing mammal. Females give birth to live young.

Litter size: Usually one pup per year.

Breeding timing: Generally spring to late summer, with births expected during the warmer months.

Gestation: Not recorded.

Fledging and weaning: Not recorded.

Breeding places: Maternity roosts may occur in hollow trees, under loose bark, in rock fissures or caves, and in buildings or other structures. The species clings to roost surfaces and groups closely together in crevices.

Colony size and recognition: Groups have been reported at up to 350 individuals, and many hundreds may roost together. An active maternity roost is indicated by pregnant or lactating females, pups, repeated bat emergence, and concentrated bat calls.

Breeding timing may shift between regions and years, particularly across the species' tropical Australian range, so use acoustic surveys, emergence watches and roost inspections to establish local activity before works begin.

  • Breeding and births: Use spring to late summer as the general breeding and birth period, with local timing confirmed by survey.
  • Dependent pups in maternity roosts: Pups may remain dependent in the roost after births, so avoid disturbance while young are present.
  • Maternity colony use: Colonial roosts may hold a large share of the local population and need protection during the breeding period.
  • Roosting and foraging activity: The species is expected to roost and forage throughout the year, using open forests, water edges, tree hollows, caves, buildings and other crevices.
  • Highest clearing risk: The highest risk is from spring to late summer, when clearing or sealing a maternity roost may harm females, pups or the colony.

Identification: Appearance and measurements

The Northern Mastiff Bat is a medium sized molossid with a robust head, thick lips and long, narrow wings. It can be difficult to identify in flight, so acoustic results, photographs and close inspection should be considered together.

The fur is generally medium brown above and slightly greyer below. The upper lip is heavily wrinkled and overhangs the lower jaw. The ears may meet or join across the top of the head.

The tail projects well beyond the edge of the thick, wrinkled membrane. The outer toes have conspicuous long, curved hairs, a useful feature during close examination.

Forearm: 46 to 52 mm

Head and body: About 8 to 9 cm

Tail: About 3.5 to 4.5 cm

Weight: About 20 to 30 g

Identification: Calls and similar species

The species uses ultrasonic echolocation calls and is best surveyed with an Anabat or similar full spectrum detector. Call identification should be checked against reference calls and, where necessary, supported by trapping or other evidence.

The White-striped Mastiff Bat, Tadarida australis, is larger and has a forearm of 57 to 63 mm. It has ears that are not joined across the head and a gular gland. Northern Mastiff Bat records can also be confused with older records under Tadarida plicata and related names.

Identification: Field signs

Northern Mastiff Bats cling to walls and crevice surfaces rather than hanging from a roost roof. They may bunch together tightly in narrow spaces.

Look for bats emerging at dusk, ultrasonic activity near a suspected entrance, droppings below crevices or hollows, and dark staining around frequently used gaps. Droppings can be difficult to distinguish from those of other small insectivorous bats, so use signs with other survey evidence.

  • Inspect suspected hollows, fissures and building gaps from a safe distance before disturbance.
  • Do not rely on the absence of visible bats during a daytime inspection. Bats may be deep inside a cavity or narrow crevice.
  • A nest is not expected. Molossid bats generally roost by clinging to the substrate.

Distribution: Australian range

In Australia, the Northern Mastiff Bat is a tropical and subtropical species recorded across northern parts of the continent. Project records should be checked against current state databases because historical records have sometimes been assigned to related names.

The species is mapped in the Northern Territory, Queensland and Western Australia. It is associated with northern Australia, including tropical areas and parts of the interior north.

Older literature includes records from northern South Australia under related names, but the species is not currently treated as a regular South Australian species in the available account.

  • Northern Territory
  • Queensland
  • Western Australia

Distribution: Overseas range

The broader range includes New Guinea and nearby island groups, including the Solomon Islands, Vanuatu and Fiji. Some accounts also suggest occurrence in the Bismarck Archipelago.

Distribution: Site planning

Before clearing, check the project area for records, suitable roost features and connected open forest or water features. A lack of previous records does not rule out a roost, because the species is not well known and many roosts are concealed.

  • Review recent fauna records and local museum or database records.
  • Record the location and condition of hollow trees, rock fissures, caves, culverts, bridges and buildings.
  • Arrange targeted bat surveys where suitable roosting features may be affected.

Habitat: Vegetation and landscape

Northern Mastiff Bats use open forests, savanna and modified landscapes, including agricultural areas. On works sites, focus on old hollow bearing trees, rocky features and structures that provide narrow protected spaces close to open flying areas.

The species is associated with open forests and savanna. It may also occur around forest edges, riparian corridors, roads and cleared areas where insects are available.

Closed forest is less suitable for direct flight, but gaps between trees and spaces below the canopy may still be used. Retain links between roost features and nearby open foraging areas where practicable.

  • Open forest and woodland
  • Savanna and forest edges
  • Riparian vegetation and water bodies
  • Agricultural areas with retained trees and shelter features

Habitat: Landforms and site features

Inspect rocky outcrops, overhangs, river banks and large old trees. A recorded rock fissure was about 500 mm long and 50 mm wide within a large overhang, showing that narrow protected gaps may be suitable.

  • Rock overhangs and fissures
  • Caves or cave-like cracks
  • Old trees with hollows, loose bark or broken limbs
  • Buildings, poles and other structures with enclosed gaps

Habitat: Habitat condition

A suitable site may have a roost feature that is not obvious from the ground. Keep pre-clearance inspections focused on the whole feature, including cavities, crevices, bark plates and access gaps.

  • Avoid filling or sealing potential roost gaps before they have been assessed.
  • Retain mature trees and rocky shelter features where they can be safely kept.
  • Consider nearby water and insect rich areas when assessing the value of a roost feature.

Foraging habitat: Foraging areas

The Northern Mastiff Bat catches insects in fast, direct flight. It generally needs open airspace and may forage above the canopy, along edges, over waterways and along roads or other linear clearings.

Look for open forest, woodland edges, savanna, water bodies and clearings that allow fast flight. The species may fly above the canopy and across gaps between trees.

Moths, grasshoppers, termites and other insects are recorded as prey. Like other molossid bats, it may take a broad range of flying insects.

  • Above or beside open forest
  • Along riparian corridors and water edges
  • Across road reserves and other linear clearings
  • Over agricultural areas where insect prey is available

Foraging habitat: Works site considerations

Clearing that removes roost trees and nearby open feeding areas can affect bats even when the roost itself is not directly disturbed. Lighting, dust and changes to water edges may also alter insect activity and flight routes.

  • Retain suitable trees and vegetation links where safe and feasible.
  • Avoid unnecessary lighting around suspected roost entrances and movement routes.
  • Manage sediment, runoff and dust near waterways and retained habitat.
  • Schedule acoustic surveys and emergence watches under suitable weather conditions.

Foraging habitat: Survey methods

Use Anabat or a similar detector to identify bat activity and movement around likely habitat. Acoustic data are useful for locating activity, but species identification may require additional evidence.

Harp traps or mist nets may be used by suitably qualified personnel where safe and permitted. Trapping should be planned to avoid injury, heat stress and disturbance to a maternity roost.

  • Deploy detectors near suspected roost entrances, water and habitat edges.
  • Record weather, time, detector location and habitat conditions.
  • Use emergence watches to identify active exits before works begin.

Breeding habitat: Maternity habitat

The Northern Mastiff Bat is treated as a colonial breeder. A roost where young are raised is a breeding place, even when the species is not listed as threatened.

Maternity roosts may occur in hollow trees, rock fissures, caves, mines, culverts, bridges and buildings. Species specific preferences are not well documented, so all suitable enclosed roost features should be assessed before disturbance.

Most microbats give birth to one pup in the warmer months, usually from spring to late summer. Treat this period as a higher risk time for disturbance unless local survey evidence supports another timing.

  • Hollow limbs and trunks in old trees
  • Deep fissures in rock, caves and mine workings
  • Gaps in culverts, bridges and buildings
  • Loose bark or enclosed spaces in large trees

Breeding habitat: Confirming a maternity roost

A maternity roost is confirmed by evidence such as pregnant or lactating females, pups, dependent young or repeated use by adult females. A single bat record does not by itself confirm a maternity roost.

Use a combination of daytime inspection, acoustic monitoring, emergence observation and, where appropriate, harp trapping or mist netting by experienced personnel.

  • Look for pups or young unable to fly.
  • Record pregnant or lactating females if captured and handled by authorised personnel.
  • Use an endoscope or pole camera where a hollow can be inspected without damaging the tree.
  • Do not insert equipment into a cavity if it may injure bats or disturb young.

Breeding habitat: Managing breeding habitat

If a maternity roost may be affected, stop and refer the feature to the project ecologist and relevant regulator. Young bats may be unable to escape exclusion devices or survive relocation.

In Queensland, tampering with a breeding place of a least concern colonial breeder requires a high risk species management program under the Nature Conservation (Animals) Regulation 2020.

  • Avoid disturbance during the likely maternity season where practicable.
  • Do not fell or seal a suspected maternity tree without an approved method and qualified supervision.
  • Use staged or soft felling for hollow bearing trees where tree removal is unavoidable.
  • Install exclusion devices only outside the maternity season and only after confirming that no bats or dependent young remain.

Sheltering habitat: Natural roosts

This bat roosts in narrow, protected spaces where it can cling to the substrate and remain in close contact with the walls. Roosts may be natural or built, and the entrance may be small or concealed.

Inspect hollows in old trees, loose bark, cracks in limbs and narrow gaps in rocky outcrops. River banks, overhangs and spaces under stones may also provide shelter.

A large overhang containing a crack about 500 mm long and 50 mm wide has been associated with the species. This indicates that a relatively small entrance can lead to a usable shelter space.

  • Hollow trunks and limbs
  • Loose bark on mature trees
  • Rock fissures, overhangs and caves
  • Gaps in rocky banks and spaces under stones

Sheltering habitat: Artificial roosts

Buildings, poles, culverts, bridges, mine workings and other structures may provide suitable enclosed spaces. Inspect roof gaps, expansion joints, bridge cavities, service penetrations and other sheltered voids before demolition or modification.

  • Buildings and roofs
  • Poles and enclosed service gaps
  • Culverts and bridges
  • Mines and other underground structures

Sheltering habitat: Inspection and exclusion

Use an endoscope or pole camera where safe, and conduct an emergence watch at dusk. Acoustic monitoring can help identify repeated use. Do not seal a gap simply because no bat is visible during the day.

Exclusion devices should allow bats to leave but prevent re-entry. They should be fitted outside the maternity season, monitored and removed or retained only under an approved plan.

  • Inspect before pruning, demolition, bridge works or tree felling.
  • Use two stage or soft felling for hollow bearing trees where required.
  • Provide replacement habitat, such as bat boxes, as a supplementary measure rather than as an automatic substitute for an occupied natural roost.
  • Have a fauna spotter catcher present for high risk works.

Colonies and breeding places: What a colony or maternity roost looks like

Colonies may contain dozens, hundreds or more bats and can occupy a single tree hollow, fissure or building void. Because one roost can hold a large share of the local population, a small entrance may represent a high consequence work area.

Bats may press together in a hollow, crack or enclosed cavity. They do not build nests and may not be visible from outside. A colony can therefore be present even when the entrance shows little activity during the day.

An active site may have repeated evening emergence, ultrasonic activity, droppings, dark staining, odour or audible chattering from inside a structure. These signs are not conclusive on their own and should be assessed together.

  • One or more narrow access gaps
  • Droppings below an entrance or on a wall
  • Dark staining or polished surfaces around a frequently used gap
  • Repeated emergence at dusk

Colonies and breeding places: Colony size and site use

Groups of up to 350 have been reported, while other descriptions refer to many hundreds. The size of a group can change between seasons and between day roosts.

Species specific site fidelity is not well documented. Treat a suitable roost as potentially reused, particularly when there is evidence of repeated activity or nearby maternity use.

  • Map every potential roost feature before clearing.
  • Record the number of bats seen, emergence duration and entrance locations.
  • Repeat checks when the project spans different seasons or work stages.

Colonies and breeding places: Recognising an active breeding place

The strongest evidence is pregnant or lactating females, pups or dependent young. Repeated use by adult females during the warmer months also warrants careful assessment.

Use acoustic monitoring, emergence watches and close inspection to build evidence. Harp trapping or mist netting should only be undertaken by experienced and authorised personnel.

  • Inspect with an endoscope or pole camera where this can be done safely.
  • Use a two stage or soft felling method for hollow bearing trees if removal is approved.
  • Keep exclusion devices away from maternity roosts unless the maternity season has ended and the method is authorised.

Colonies and breeding places: Why colonies need special care

Disturbing one entrance can affect many bats at once. If young are present, exclusion, felling, demolition or sealing may trap them inside or separate them from their mothers.

In Queensland, the colonial breeder provisions apply even though the species is least concern. Confirm the required species management program before works affect a suspected breeding place.

  • Stop work if bats, pups or a large colony are found unexpectedly.
  • Protect the roost and establish a suitable work exclusion area under the project fauna plan.
  • Use bat boxes only as supplementary habitat. They do not replace an occupied maternity roost without an approved assessment and plan.

Threats: Loss of hollow trees and roost features

The main risks on works sites are the loss, sealing or disturbance of roosts and the removal of nearby feeding habitat. Least concern status does not remove the need to protect an active colony or breeding place.

Clearing old trees can remove hollows, loose bark and broken limbs used for shelter or breeding. Rocky fissures, caves, mine workings and overhangs can also be lost through excavation, blasting or stabilisation works.

  • Survey hollow bearing trees before clearing.
  • Retain suitable trees and rock features where safe and practicable.
  • Use staged or soft felling where an occupied hollow tree must be removed.
  • Inspect felled sections and provide for safe capture and release if bats are exposed.

Threats: Disturbance to colonies and breeding places

Demolition, bridge work, cave visits, tree trimming and sealing of building gaps can disturb colonies. Work during the maternity season creates a higher risk of trapping or injuring dependent young.

  • Confirm whether a roost is active before disturbance.
  • Use emergence watches and acoustic monitoring to guide timing.
  • Do not seal entrances or install exclusion devices when dependent young may be inside.
  • Obtain the required Queensland high risk species management program before tampering with a breeding place.

Threats: Changes to feeding habitat

Agricultural clearing, land degradation, removal of riparian vegetation and loss of open forest can reduce feeding habitat. Waterways and edges may be especially useful because they provide open flight space and insect activity.

  • Retain open forest edges, riparian vegetation and connected habitat where possible.
  • Limit unnecessary lighting around retained habitat and water.
  • Control sediment, runoff and dust near waterways and wet areas.
  • Avoid removing all mature trees around a known or suspected roost.

Threats: Cave, mine and structure impacts

Mining, cave modification, access works and changes to bridges, culverts or buildings can remove or disturb roost spaces. Human activity near cave colonies can cause repeated disturbance even when no construction occurs inside the roost.

  • Inspect caves, mine workings, bridges, culverts and buildings before access or modification.
  • Control visitor access to known colonies where required by the management plan.
  • Keep fauna spotter catchers informed of all potential roosts and unexpected bat activity.
  • Record and report any colony, maternity evidence or injured bat found during works.

Survey methodology: 1. Desktop assessment

Northern Mastiff-bats are fast-flying microbats that can be difficult to identify by sight. Use several survey methods, especially where hollow-bearing trees, caves, buildings, bridges, culverts or other enclosed roosts may be affected.

Map hollow-bearing trees, loose bark, rock fissures, caves, mines, culverts, bridges, buildings and other enclosed structures within and near the work area.

Check previous records and local knowledge for roosts, colonies and feeding areas. Consider open forest, forest edges, waterways and open areas above the canopy as likely foraging habitat.

Treat any site where young may be raised as a breeding place. Northern Mastiff-bats are a colonial breeder, even though species-specific information about maternity roosts and site fidelity is limited.

  • Review state and territory records for the Northern Territory, Queensland and Western Australia.
  • Identify proposed clearing, demolition, vibration, lighting, blasting, excavation and access routes.
  • Retain potential roost structures in the design wherever practicable.

Survey methodology: 2. Acoustic and activity surveys

Use Anabat or a similar ultrasonic detector to survey flight activity and commuting routes. Survey open forest, canopy gaps, waterways, forest edges, roadways and the airspace around potential roosts.

Undertake repeated surveys in suitable weather during the warmer months, when microbat colonies are more likely to be active. Avoid strong wind, heavy rain and other conditions that reduce bat activity or detector performance.

Use more than one detector where the site is large or contains several potential roost areas. Acoustic data can indicate activity, but usually cannot confirm a maternity roost on its own.

  • Record detector location, date, start and finish time, weather, habitat, equipment settings and files retained.
  • Record species identifications and confidence, call sequences, activity levels and likely flight routes.
  • Have difficult call identifications checked by an experienced microbat ecologist.

Survey methodology: 3. Roost and colony surveys

Watch potential roosts at emergence and return times. Inspect tree hollows, loose bark, poles, buildings, bridges, culverts, caves and rock fissures where access is safe and authorised.

Use an endoscope or pole camera to inspect suitable hollows and cavities without entering or damaging the roost. Do not enter a cave or enclosed roost without a site-specific safety and fauna plan.

Use harp traps or mist nets only under appropriate authority and with experienced handlers. These methods can assist identification, but they must not replace a careful roost inspection or emergence watch.

  • Look for repeated bat traffic, concentrated guano, urine staining, rubbing marks, scratch marks, noise, odour and bats clustered in a cavity.
  • Treat pregnant or lactating females, pups, dependent young, repeated adult traffic and a group using the same cavity as evidence of an active breeding place.
  • Record the roost structure, entrance dimensions where safe, surrounding habitat, number of bats observed, survey duration and evidence of breeding.

Survey methodology: 4. Interpreting survey results

A single quiet survey does not show that a roost is unused. Bats may move between roosts, remain deep in a cavity or be inactive in poor weather.

Northern Mastiff-bats have been recorded in groups of up to 350, and other accounts describe many hundreds together. Plan for a large concentration of animals if a colony is found.

There is no established migration schedule to use for this species. Plan around the general microbat breeding period, usually spring to late summer, unless local evidence supports a different timing.

  • Keep potential roosts under consideration until repeat surveys and the ecologist's assessment support a decision.
  • Use local weather data and dusk observations to explain low activity results.
  • Escalate any large group, maternity evidence or repeated use to the project ecologist before disturbance.

Before habitat disturbance: 1. Approvals and legal checks

Plan avoidance before machinery arrives. Northern Mastiff-bats are least concern nationally, but their colonies and breeding places need additional care because one roost can contain a large share of the local population.

Confirm the applicable Commonwealth, state and territory requirements before clearing or demolition starts. Assess whether the action may affect a matter of national environmental significance and whether an EPBC referral is needed.

In Queensland, treat the species as a least concern colonial breeder. Tampering with its breeding place requires a high risk species management program under the Nature Conservation (Animals) Regulation 2020, rather than the low risk program used for other least concern animals.

Obtain any required Queensland, Northern Territory or Western Australian fauna permits, rehabilitation permissions and authority for capture, handling, exclusion or relocation. Confirm requirements with the relevant regulator and permit holder.

  • Keep approvals, permits, the SMP, method statements and contact details at the site office.
  • Check conditions attached to development approval, clearing approval, environmental authority and fauna permits.
  • Do not rely on the species' least concern status as permission to disturb a colony or breeding place.

Before habitat disturbance: 2. Avoidance and timing

Redesign the work to retain hollow-bearing trees, caves, rock fissures, buildings, bridges, culverts and other structures used by bats. Retain connected flight paths and nearby open foraging habitat where practicable.

Schedule high impact work outside the local maternity period wherever possible. Microbats commonly raise young in the warmer months, usually spring to late summer.

Do not apply a generic buffer without an ecological assessment. Set a site-specific no-go area around each active roost, colony or breeding place, taking account of noise, vibration, lighting, access and the structure's stability.

  • Avoid felling or demolition when pups are present or females are pregnant or lactating.
  • Turn off or shield unnecessary lighting near roost entrances and flight paths.
  • Use a staged approval process so work does not proceed until the roost status is resolved.

Before habitat disturbance: 3. Pre-clearance survey and exclusion

Complete a pre-clearance inspection shortly before disturbance. Recheck all hollow-bearing trees and structures that will be removed, damaged or exposed.

Use an emergence watch, acoustic monitoring and internal inspection where safe. Confirm whether bats are present and whether the site is a maternity roost before installing an exclusion device.

Where exclusion is appropriate, use a one-way device only outside the maternity season and under an approved method statement. Do not exclude bats if pups may be trapped inside.

  • Have the fauna ecologist nominate trees and structures for retention, staged removal or controlled felling.
  • Use two-stage or soft felling for hollow-bearing trees when removal is authorised. First remove non-hollow sections, then lower hollow sections carefully and allow time for inspection.
  • Leave a retained hollow section undisturbed when safe and practicable.

Before habitat disturbance: 4. Induction and site controls

Brief all workers, operators and subcontractors before work starts. Show them the no-go areas, roost locations, exclusion devices, stop-work process and fauna contacts.

Give the spotter catcher authority to stop work immediately if a bat, colony, breeding place or unexpected roost is found.

Mark retained trees and structures clearly. Fence or sign exclusion areas and keep machinery, spoil, vibration and lighting outside them.

  • Explain that bats must only be handled by authorised and trained people.
  • Include safe work requirements for caves, roofs, bridges, poles, elevated work and confined spaces.
  • Keep a current site map showing cleared areas, retained habitat, active roosts and approved work fronts.

During habitat disturbance: 1. Sequential clearing

Use a slow, observable clearing sequence. Stop work whenever the actual site conditions differ from the approved plan or when a colony, breeding place or injured bat is found.

Clear in small, supervised stages from the disturbed area towards retained habitat. Start each stage only after the spotter catcher and site supervisor confirm that controls are in place.

Use soft felling for hollow-bearing trees. Lower limbs and hollow sections slowly rather than dropping them. Pause after each section so the fauna team can inspect for bats.

Keep machinery away from retained roosts and avoid blocking likely flight paths with stockpiles, temporary lighting or access equipment.

  • Inspect each hollow, cavity, loose bark section and cut piece before it is moved or loaded.
  • Keep removed hollow sections stable and shaded while the fauna team assesses them.
  • Record the tree or structure number, action taken, bat observations and final disposition.

During habitat disturbance: 2. Stop-work response

Stop work if a bat is seen, heard in a cavity, captured, injured or found under bark. Also stop if a previously unrecorded colony, active breeding place or roost is identified.

Secure the area and keep workers, machinery, dogs and unnecessary lighting away. Contact the fauna spotter catcher and project ecologist before work resumes.

If a maternity roost is found, do not remove, seal, relocate or exclude the bats under the ordinary clearing sequence. Reassess the approval, SMP, timing and site controls.

  • Inspect the roost only by an authorised person using safe equipment.
  • Determine whether pups, pregnant females or lactating females are present.
  • Update the site plan and obtain written approval for any revised action before restarting work.

During habitat disturbance: 3. Handling and release

Only authorised and trained fauna personnel may handle bats. Use appropriate gloves, a secure cloth bag or approved container, and keep handling time as short as possible.

Do not attempt to pick up a bat with bare hands. Keep people away from flying bats and do not chase them through the work area.

Release a healthy animal only under the approved fauna procedure, at a suitable nearby location with shelter and safe flight access. Do not relocate a colony without specialist advice and approval.

  • Check the animal for injury, dehydration, abnormal behaviour and signs of entanglement.
  • Keep the container cool, quiet, shaded and protected from predators.
  • Record the capture, identification, condition, time, location, handling and release or transfer details.

During habitat disturbance: 4. Injured or dependent bats

Place an injured, grounded, dead or dependent bat under the project fauna procedure. Contact the authorised wildlife carer, veterinarian or rehabilitation provider listed in the permit and induction materials.

Do not feed, water or treat the bat unless directed by the authorised carer or veterinarian. Keep it separate from machinery, noise, heat and direct sun.

Treat a pup or lactating female as a possible breeding-place incident. Search the immediate roost structure under the ecologist's direction and protect the site until the association is resolved.

  • Photograph the animal and location only when this can be done without extra disturbance.
  • Use a clean, secure container and label it with the date, time and location.
  • Report mortalities, injuries, entanglements and failed exclusions to the project manager and relevant regulator where required.

During habitat disturbance: 5. Field records

Maintain a fauna event log throughout clearing and construction. Make entries on the day and link them to the relevant tree, structure, work front or permit condition.

Record negative findings as well as captures and incidents. This supports decisions about whether a roost remains active and whether additional survey is needed.

Have the fauna spotter catcher and supervisor sign off each completed clearing stage.

  • Record weather, work activity, machinery, observers and survey effort.
  • Record roost evidence, colony estimates, breeding evidence, photographs, call files and GPS locations.
  • Record stop-work events, instructions given, approvals received and the time work restarted.

After habitat disturbance: 1. Post-clearance inspection

Check the work area after each clearing stage and after any exclusion or relocation. Use the results to adjust controls before the next stage begins.

Inspect felled trees, hollow sections, demolition materials and the ground around the work area for live, injured or dead bats. Check retained trees and nearby structures for disturbance or new damage.

Complete a final emergence or acoustic check where a roost was excluded, removed or close to the work area. Repeat checks if bats continue to show concentrated activity.

Do not declare a site clear solely because no bat was seen during daylight.

  • Check cavities, bark slabs, roof spaces, bridge joints, culverts and rock fissures that were exposed by the work.
  • Remove hazards such as open pipes, uncovered pits, unsecured netting and deep containers.
  • Keep retained roost structures protected until the ecologist confirms that the work area is safe.

After habitat disturbance: 2. Relocated animals and exclusions

Inspect any approved release location and exclusion device for signs of continued use, trapped animals or failure. Check that the device has not been blocked, damaged or bypassed.

Monitor relocated animals using acoustic activity, emergence observations or other methods suited to the site. A short-term absence from the original roost does not prove that relocation has succeeded.

If bats return to the structure, pups are found, or animals are trapped, stop the relevant work and contact the ecologist.

  • Record release location, weather, habitat condition and follow-up observations.
  • Remove exclusion devices only when the approved method and ecologist confirm that this is safe.
  • Do not seal a cavity containing bats or dependent young.

After habitat disturbance: 3. Reporting and compliance

Prepare a fauna report that links survey results, clearing stages, incidents, approvals, mitigation and outcomes. Submit records to the regulator, approval holder and project file as required.

Report any breach of a permit, SMP or approval condition promptly. Include the corrective action and whether further survey or monitoring is needed.

Retain acoustic files, photographs, GPS data, inspection sheets, capture records and rehabilitation records in an accessible project archive.

  • Summarise roosts retained, roosts removed, colonies detected and animals handled.
  • List all injuries, mortalities, breeding-place findings and stop-work events.
  • Document any change to timing, buffers, exclusion, lighting or clearing methods.

After habitat disturbance: 4. Incident review

Review each unexpected bat event with the project manager, fauna ecologist, spotter catcher and relevant contractor. Identify whether the survey, induction, design or work sequence failed to detect or protect the animal.

Update the risk assessment and method statement before the next work stage. Share the lesson with all crews, including night crews and subcontractors.

Use the review to improve future detection of hollow roosts, colonies and breeding places on the project.

  • Check whether survey timing and weather were suitable.
  • Check whether the stop-work authority was understood and used.
  • Add new roost records, flight routes and habitat observations to the site map.

Rehabilitation actions: 1. Restore roosting habitat

Rehabilitation should restore roosting, breeding and feeding opportunities, not just ground cover. Northern Mastiff-bats commonly use tree hollows, loose bark, poles, buildings, caves and other crevices, and they forage over open forest and water.

Retain standing hollow-bearing trees wherever safe. Protect retained trees from root damage, soil compaction, fire, pruning, lighting and later maintenance works.

Retain suitable fallen hollow sections where they can remain stable and safe. Preserve rock fissures, caves, culverts, bridges and buildings that are confirmed or likely roosts.

Restore a range of tree ages and species so future hollows develop over time. Avoid removing loose bark or sealing natural crevices unless required for safety and approved by the ecologist.

  • Fence retained trees and roost structures during rehabilitation works.
  • Use local native species suited to the site and its future canopy structure.
  • Keep access, weed control and monitoring activities away from occupied roost entrances.

Rehabilitation actions: 2. Supplementary roost structures

Use bat boxes or other artificial roost structures only as a supplementary measure. They do not replace a natural maternity roost or justify removal of a colony.

Select a structure and placement suited to local microbats, with advice from a qualified bat ecologist. Consider temperature, shade, weather exposure, predator access, nearby flight paths and maintenance access.

Artificial structures can assist where natural hollows are scarce, but occupancy is not guaranteed for this poorly known species.

  • Install boxes or roost structures before or soon after habitat disturbance where the approved plan identifies a need.
  • Use more than one suitable structure where the habitat is extensive or several roost opportunities were lost, without assuming that a fixed number will replace a colony.
  • Inspect structures only when authorised and outside periods when pups may be present.

Rehabilitation actions: 3. Rebuild feeding habitat and water features

Re-establish open forest structure, canopy gaps, forest edges and safe flight corridors. Northern Mastiff-bats hunt insects in fast, direct flight and may forage above the canopy or over water.

Protect waterways and restore native vegetation around them without creating dense barriers across established flight routes. Retain insect-producing vegetation and avoid unnecessary insecticide use.

Manage erosion, sediment, dust and runoff so nearby water and foraging areas remain suitable.

  • Use local native plants that provide a layered but open habitat structure.
  • Keep temporary lighting away from water, roosts and flight corridors, and use the lowest practical intensity during night works.
  • Avoid broad-spectrum insecticide application near retained roosts and foraging areas.

Rehabilitation actions: 4. Weeds and site maintenance

Control weeds that suppress natural regeneration or obstruct access to retained roost structures. Use methods that avoid poisoning bats, contaminating water or disturbing occupied cavities.

Plan maintenance around known roosts and breeding places. Reinspect trees, buildings, culverts, bridges and artificial boxes before pruning, repair, demolition or vegetation removal.

Keep rehabilitation records so changes in roost use and habitat condition can be tracked.

  • Use staged weed control and retain native shelter around roost entrances.
  • Do not burn, fumigate, spray or seal a roost without ecological assessment and approval.
  • Remove fencing, waste, netting and construction materials that could entangle or trap bats.

Rehabilitation actions: 5. Long-term monitoring

Monitor retained and replacement roost structures through the seasons, with additional attention during the warmer breeding period from spring to late summer. Use emergence watches, acoustic detectors and inspections suited to the structure.

Track occupancy, colony use, breeding evidence, roost condition, nearby lighting and habitat recovery. Interpret non-detection cautiously because roost use may change between sites.

Set review points in the rehabilitation plan and adjust planting, lighting, weed control or protection measures when monitoring shows a problem.

  • Record dates, weather, observer effort, detector locations, call files and roost observations.
  • Record whether bats are using natural or artificial structures and whether dependent young are present.
  • Continue monitoring for as long as required by the approval, SMP or ecological risk assessment.

Sources