Gould's Long-eared Bat (Nyctophilus gouldi)

Conservation status

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

Breeding season

Timing varies across the species' broad range, but the following pattern is supported for southern populations and the documented breeding cycle. Winter torpor or hibernation overlaps with mating, followed by implantation in September, births in late spring or early summer and young flying with adults from about January.

The documents do not describe migration. The timing pattern is therefore local and seasonal rather than migratory.

• Mating and torpor: Mating takes place mainly in April. Southern animals can enter torpor or hibernate during April to September, with males arousing periodically to mate with females.
• Implantation and late winter torpor: Ovulation, fertilisation and implantation occur in September after sperm storage. Winter torpor or hibernation can continue through September in southern populations.
• Births and dependent young: One or two young are born in late spring or early summer. Young are fully furred at about four weeks and are weaned at about six weeks.
• First flights and local roost movement: Young begin flying with the mother at about four weeks and can be seen flying in January. Adults change roosts often, usually within a local set of trees near a creek line.
• Highest clearing risk: Risk is highest from September to January because implantation, births, dependent young and first flights occur then. April to September also requires caution because southern animals may be torpid or hibernating and mating occurs during this period.

Identification

Gould's Long-eared Bat is recognised by its very large, broad ears and small, simple noseleaf. It is a small, grey to greyish-brown bat that can be difficult to identify confidently from a brief flight view.

The dorsal fur is slate-grey to greyish brown and the underparts are ashy grey. The rostrum, ears and wing membranes are dark greyish brown. The ears are broad, bluntly rounded and heavily ribbed on the inner surface, with a furred band between the ears.

The nose has two ridges, one farther along the muzzle and one immediately above the nostrils, separated by a vertical groove. The tragus is small and bluntly rounded.

Head and body: 44 to 52 mm

Tail: 39 to 41 mm

Forearm: 36.3 to 47.7 mm

Weight: 5.2 to 16.5 g

Ear: 24.3 to 30.1 mm

Identification: Sex and acoustic clues

Females commonly roost in groups of 20 or more. Males usually roost alone or in temporary groups of fewer than six, although sex cannot be assigned reliably from size or appearance alone in the field.

The echolocation call is a steep frequency-modulated sweep with peak frequencies of about 50 to 53 kHz. Typical recordings do not readily separate this species from other long-eared bats, so acoustic identification should be treated cautiously.

Identification: Field signs and similar species

Daytime evidence is most likely to be a bat or group of bats in a low tree hollow or fissure. Individuals may also be found in roofs and, possibly, caves. The species switches roosts often, generally between a set of trees near a creek line.

The most reliable separation from other long-eared bats requires close examination of the very large ears, noseleaf, fur pattern and measurements. The call alone is not a dependable diagnostic feature. The supplied documents do not describe diagnostic tracks, scats, nests or eyeshine.

• Inspect low hollows, fissures and suitable roof spaces before removing trees or structures.
• Do not rely on a bat detector recording alone where other long-eared bats occur.
• Use photographs, measurements and an experienced bat ecologist when a captured or grounded individual must be identified.

Distribution: Australian range

Gould's Long-eared Bat has a broad but discontinuous Australian distribution. The supplied material identifies populations in south-western Western Australia, eastern and south-eastern Queensland, central and eastern New South Wales, Victoria and south-eastern South Australia.

The species occurs in south-western Western Australia and in eastern and south-eastern Queensland, including Fraser Island. In New South Wales it is recorded through central and eastern areas, with records extending into Victoria and south-eastern South Australia.

The documents do not provide an IBRA bioregion list or a complete state-by-state map. They also note that the Western Australian population may represent a distinct species pending further research.

States and regions identified: South-western Western Australia; eastern and south-eastern Queensland; central and eastern New South Wales; Victoria; south-eastern South Australia.

Elevation: Recorded from sea level to about 1,240 m in Victoria.

Distribution: Strongholds and population information

No national population estimate, density estimate, confirmed stronghold or quantitative population trend is provided. The species is described as widespread and common overall, but local populations can be affected by forest thinning, fragmentation and artificial light.

The supplied project information records the species as Least Concern nationally and lists it as Endangered in South Australia. State and project-specific advice should therefore use the applicable current jurisdictional listing.

National conservation status in supplied material: Least Concern

South Australian status in supplied project information: Endangered

Population size: Not provided

Population trend: No quantitative national trend provided

Habitat: Vegetation communities

The species uses a wide range of wet to semiarid habitats, but the available information points to a preference for forest and woodland with dense understorey and suitable low tree hollows. It can occur from sea level to about 1,240 m in Victoria.

Recorded habitats include rainforest, wet and dry sclerophyll forest, Melaleuca woodland, river red gum vegetation along waterways, other woodlands and Acacia shrublands.

The species is associated with humid temperate regions in Western Australia. In taller forests, a dense understorey appears to support roost establishment.

• Retain mature and hollow-bearing trees in forest, woodland and riparian vegetation.
• Treat dense understorey and creek-line vegetation as potential habitat, not only intact closed forest.
• Assess scattered trees within cleared or urbanised areas because roosting trees can be used within otherwise fragmented habitat.

Habitat: Climate and structure

The documented habitat range extends from wet to semiarid environments. In Victoria, records reach approximately 1,240 m elevation.

The supplied project assessment identifies eucalyptus forest or woodland and hollow-bearing trees as relevant habitat attributes. The species can use small forest remnants, including remnants in an urban matrix, but artificial light and surrounding urban land can restrict use of the site.

Climate range: Wet to semiarid habitats

Recorded elevation: Sea level to approximately 1,240 m in Victoria

Key structural features: Tree hollows or fissures, dense understorey, tall forest and creek-line trees

Foraging habitat: Diet and feeding method

Gould's Long-eared Bat feeds on insects in and below the canopy. It combines echolocation with active listening and often hunts close to the ground or gleans prey from foliage and the ground surface.

Moths and beetles are usual prey. Crickets, flies, cockroaches, ants, bugs and spiders are also eaten.

The species generally forages on the wing or gleans prey from foliage and the ground. Active listening is used extensively to detect prey, while echolocation is used mainly for orientation in unfamiliar habitat and for detecting some prey on foliage or the ground.

Flight is slow and close to the ground, in large circles well below the canopy. This makes low vegetation, forest edges and understorey structure relevant when assessing foraging habitat.

Main prey: Moths and beetles

Additional prey: Crickets, flies, cockroaches, ants, bugs and spiders

Foraging height: Usually close to the ground and well below the canopy

Foraging habitat: Foraging area and movement

In a small remnant forest patch within an urban matrix, nightly foraging areas were no larger than 80 ha. Individuals moved an average of less than 300 m from their roosts each night and used up to 100 percent of the remnant forest.

Individuals almost never entered urban areas in that study, indicating that lighting and developed land can restrict access to otherwise nearby foraging habitat. Roosts are often changed within a set of trees near a creek line.

Nightly foraging area in one urban remnant: No more than 80 ha

Average nightly movement from roost: Less than 300 m

• Maintain dark connections between roost trees, understorey and nearby feeding areas where practicable.
• Avoid directing construction lighting into creek lines, forest remnants and low understorey used for night foraging.
• Consider the full remnant and nearby creek-line vegetation when assessing the effect of clearing individual roost trees.

Breeding habitat: Breeding biology

Breeding is seasonal, with mating beginning during the cooler months and births in late spring or early summer. Females use communal roosts, and young remain associated with the mother until they are able to fly and feed independently.

Mating takes place mainly in April while adults are hibernating. Males can arouse periodically to mate with torpid females through winter until September. Ovulation, fertilisation and implantation occur in September, and females are likely to store sperm until then.

Females give birth once a year to one or two young. The twinning rate is reported as 50 percent in late October. Young are fully furred at about four weeks, begin flying with the mother at that age, and are weaned at about six weeks.

Young bats can be seen flying in January, generally with an adult or two. Females reach sexual maturity at 7 to 9 months and males at 12 to 15 months.

Breeding frequency: Once each year

Mating: Mainly April, with mating possible through winter until September

Births: Late spring or early summer

Litter size: One or two young

Twinning rate: 50 percent in late October

Weaning: About 6 weeks

Female maturity: 7 to 9 months

Male maturity: 12 to 15 months

Gestation: A fixed gestation period is not provided. Delayed development occurs after sperm storage, with implantation in September.

Lifespan: Not provided

Breeding habitat: Breeding habitat features

Breeding colonies are most likely to depend on suitable daytime roosts, particularly tree hollows and fissures close to the ground. Females commonly roost in groups of 20 or more.

Retain connected groups of suitable trees, especially near creek lines, because the species changes roosts frequently within a local set of trees. Avoid disturbance to known roost trees during winter torpor and the late spring to summer period when young are dependent.

• Inspect and retain low hollow-bearing trees before clearing.
• Where roost removal cannot be avoided, obtain species-specific advice on timing, exclusion and replacement roost options.
• Keep understorey and dark flight paths around retained roost trees where practicable.

Sheltering habitat: Roost types

Day roosts are usually in tree hollows or fissures close to the ground. Roosts can be changed often, so a single empty inspection does not demonstrate that a tree is unused.

Known daytime refuges include tree hollows and fissures close to the ground. The species has also been recorded in roofs and possibly in a cave in northern Queensland.

Females often form colonies of 20 or more. Males are usually solitary or occur in temporary groups of fewer than six. In southern populations, individuals can remain torpid or hibernate for periods of up to 11 days during winter.

Female roost group: Typically 20 or more individuals

Male roost group: Usually alone or in transient groups of fewer than six

Winter torpor or hibernation: Periods of up to 11 days are reported

Roost dimensions: Not provided

• Check hollow-bearing trees, fissures and roof spaces before demolition, tree removal or building renovation.
• Pay particular attention to low cavities and trees near creek lines.
• Do not assume that an unoccupied hollow is unimportant because roost use can change frequently.

Sheltering habitat: Roost assessment on worksites

The supplied material does not give a minimum hollow entrance size, preferred tree diameter, cavity depth or roost temperature. Site assessments should therefore record the tree species, diameter, hollow location, entrance dimensions, cavity condition, height above ground, surrounding canopy and understorey, and proximity to creeks.

Southern animals may be torpid during April to September. Disturbance or removal of a roost during this period can affect animals that are inactive and less able to escape.

• Use an experienced bat ecologist where a hollow-bearing tree or roof is scheduled for removal.
• Record potential roost trees even when no bats are visible during a daytime inspection.
• Plan works to avoid known roosts and maintain nearby alternative hollows.

Threats: Clearing and fragmentation

The main documented pressures are loss and fragmentation of forest habitat, removal of hollow-bearing trees and artificial light. The supplied documents provide limited species-specific evidence for roads, disease, hydrology change and direct fire effects.

Forest thinning and habitat fragmentation associated with urbanisation and agricultural expansion are identified threats. Clearing can remove tree hollows and fissures used for daytime roosting, as well as understorey and low flight paths used for feeding.

The species can use small remnants, but recorded individuals almost never entered urban areas in one study. This indicates that fragmentation and developed land can reduce access to nearby foraging habitat.

• Retain hollow-bearing trees and creek-line vegetation wherever practicable.
• Assess indirect effects on the remaining remnant, including loss of dark flight paths and reduced understorey cover.
• Treat removal of a single suitable tree as potentially significant if it forms part of a local roost set.

Threats: Lighting and construction disturbance

Artificial light may restrict foraging in urban and bushland mosaics. Construction lighting can therefore reduce access to feeding habitat even where vegetation is retained.

Winter torpor or hibernation, maternity roosting and the period when young are learning to fly are sensitive times for work near occupied roosts.

• Keep lighting away from retained roost trees, creek lines and low understorey.
• Use shielding, low-intensity lighting and temporary lighting periods where project requirements allow.
• Obtain specialist advice before disturbing a suspected occupied roost.

Threats: Fire, roads, disease and hydrology

The supplied documents identify eucalyptus forest or woodland, hollow trees and wetland or creek-associated habitat attributes in the broader project assessment, but they do not provide species-specific evidence on fire mortality, road collision, disease or hydrology change.

For project assessment, these pressures should be considered where they remove hollow trees, alter creek-line vegetation, increase night lighting or reduce connected forest. Any conclusion about population effects should be supported by site evidence and current jurisdictional advice.

• Inspect trees affected by fire or hazard reduction for surviving hollows and potential roost use before removal.
• Check whether roads and drainage works sever dark movement routes between roost trees and feeding habitat.
• Escalate sick, injured or unusually grounded bats to a qualified wildlife carer or veterinarian.

Survey methodology: 1. Desktop habitat assessment

Gould's Long-eared Bat roosts in tree hollows and fissures, often close to the ground, and forages below the canopy in forest and woodland. Surveys should focus on retained and proposed-clearing areas with suitable hollow-bearing trees, dense understorey and nearby creek lines or other moist habitat.

Roost features: Tree hollows and fissures, often close to the ground; roofs and possibly caves have also been recorded.

Typical habitat: Wet to semiarid habitats, including rainforest, wet and dry sclerophyll forest, Melaleuca woodland, river red gum woodland, waterways and Acacia shrubland.

• Map wet and dry sclerophyll forest, rainforest, Melaleuca woodland, river red gum woodland, Acacia shrubland, waterways and dense understorey within and near the project area.
• Identify hollow-bearing trees, fissures, mature trees close to creek lines, dense understorey and connected forest patches before selecting survey sites.
• Check whether the project occurs in South Australia, where the supplied project status records the species as Endangered, and confirm current state requirements before fieldwork.

Survey methodology: 2. Detector surveys

Peak frequency: Usually 50 to 53 kHz, with a reported mean of about 51.8 kHz.

Foraging height: Close to the ground and well below the canopy.

• Deploy ultrasonic detectors around hollow-bearing trees, creek lines, dense understorey, forest edges and proposed clearing areas during the active evening period.
• Begin observations before dusk and continue through the main evening foraging period, because bats leave roosts around dusk.
• Use call analysis cautiously, because the species' steep frequency-modulated call cannot be easily distinguished from other long-eared bats using typical recordings.
• Record detector location, date, start and finish time, weather, habitat, nearby roost features and identification confidence for every station.

Survey methodology: 3. Roost and emergence searches

Roost switching: Individuals switch roosts often, generally between a set of trees close to a creek line.

Winter torpor: Southern populations may remain torpid for periods of up to 11 days from April to September.

• Inspect trees proposed for removal for hollows and fissures close to the ground, with particular attention to trees near creek lines and groups of mature trees.
• Where a suitable hollow can be safely viewed, undertake a dusk emergence watch from before sunset until bats have left or activity has clearly ceased.
• Search roofs and other structures where present, while recognising that the species is primarily associated with tree hollows and fissures.
• Repeat searches where winter torpor, poor visibility or an obstructed hollow could reduce detection.

Survey methodology: 4. Complementary capture and habitat checks

Nightly movement: Individuals moved on average less than 300 metres from roosts in one small remnant forest patch.

Recorded nightly foraging area: No larger than 80 hectares in that study.

• Use appropriately designed harp traps or other approved bat-capture methods only where the survey team is authorised, trained and operating under the relevant animal ethics, wildlife and project approvals.
• Place capture equipment along likely low-level flight paths near creek lines, hollow-bearing trees and forest edges, rather than relying on acoustic identification alone.
• Do not use capture as a substitute for inspecting hollow-bearing trees, because the species may roost in hollows and fissures close to the ground and may switch roosts frequently.
• Schedule trapping and handling to avoid cold, wet or otherwise unsafe conditions, and release animals promptly at the point of capture unless an approved relocation or rehabilitation procedure applies.

Survey methodology: Minimum effort and reporting

• Set survey effort, number of detector nights, emergence watches, capture nights and survey area from the project risk, habitat extent and current state or territory survey requirements.
• Survey more than one night where weather, access, habitat complexity, winter torpor or uncertain call identification could reduce detection.
• Document methods, equipment, calibration, locations, timing, weather, habitat, raw files, call identifications, captures, injuries and negative results.
• Submit confirmed records and relevant acoustic or photographic evidence to the relevant state or territory wildlife database.
• Have records and identification reviewed by a suitably experienced bat ecologist where the result could affect clearing, approvals or mitigation.

Before habitat disturbance: Avoid and minimise

Avoid clearing suitable roosting and foraging habitat wherever practicable. The main project risks are removal of hollow-bearing trees, loss of connected forest near creek lines, fragmentation of dense understorey and disturbance during periods when bats are torpid.

Female roost groups: Typically 20 or more individuals.

Male roosting: Males roost alone or in transient groups of fewer than six.

• Retain hollow-bearing trees, fissure-bearing trees, mature trees near creek lines and dense understorey within retained forest patches.
• Retain connected vegetation between roost trees, waterways and known or potential foraging areas.
• Keep clearing footprints away from creek lines, wet forest, river red gum woodland and other habitat identified during the desktop and field assessment.
• Avoid removing groups of nearby roost trees, because individuals may move between a set of trees and females may roost in colonies of 20 or more.

Before habitat disturbance: Approvals and timing

• Confirm the current EPBC Act status and all state or territory approvals before works begin; the supplied project information records the species as not listed under the EPBC Act and Endangered in South Australia.
• Obtain any required state wildlife permits for survey, capture, handling, relocation or rehabilitation.
• Plan intrusive work outside the April to September winter torpor period where practicable, particularly in southern populations and where suitable tree hollows will be removed.
• Stage clearing so retained habitat and connected roost trees remain available while each work area is assessed and completed.

Before habitat disturbance: Site preparation

• Complete a pre-clearance inspection of all trees, structures and ground features that could provide roosting or movement habitat.
• Mark trees to be retained, trees approved for removal, exclusion zones, access routes and no-go areas before machinery arrives.
• Use exclusion fencing where it can protect retained trees, dense understorey, creek-line vegetation and other nominated habitat without creating a hazard for bats or machinery.
• Brief the fauna spotter catcher, operators and supervisors on stop-work triggers, handling limits, contact arrangements and the approved fauna management plan.

During habitat disturbance: Daily controls

Clearing must proceed under direct ecological control where suitable bat habitat is present. The fauna spotter catcher should work ahead of machinery and maintain a clear line of communication with the operator and site supervisor.

• Inspect exclusion fencing, tree protection measures and no-go areas at the start of each shift.
• Confirm weather and visibility are suitable for the planned work, and postpone high-risk activities when conditions make inspection, handling or release unsafe.
• Clear progressively, with the spotter catcher checking each work area before trees, understorey or structures are disturbed.
• Keep machinery outside marked exclusion zones until the spotter catcher has released the area for work.

During habitat disturbance: Habitat feature handling

Shelter features: Tree hollows and fissures close to the ground are the documented primary roost features; roofs and possibly caves have also been recorded.

• Do not fell a hollow-bearing or fissure-bearing tree until the fauna spotter catcher has inspected it and the approved clearing procedure has been applied.
• Where approved, use staged or controlled felling so fauna can leave safely and the tree can be checked before removal or sectioning.
• Retain trees with hollows close to the ground, nearby mature trees and connected understorey whenever possible.
• Inspect logs, dense vegetation, buildings and other potential shelter features before they are moved or demolished.
• Protect creek lines, wet forest and other moist habitat from unnecessary vehicle access, sediment movement and spoil placement.

During habitat disturbance: Animal encounters and stop work

• Stop machinery immediately if a bat is seen, heard leaving a tree or structure, found on the ground, trapped, injured or exposed during clearing.
• Keep personnel and machinery clear while the authorised fauna spotter catcher assesses the animal from a safe distance.
• Only suitably authorised and trained personnel may capture, handle, transport or release the bat.
• Release an uninjured bat into nearby retained habitat only under the approved fauna management plan and at a time and location that do not expose it to avoidable heat, cold, predators or traffic.
• Take an injured bat to an appropriately equipped veterinarian or licensed wildlife carer as soon as practicable.
• Do not resume work until the fauna spotter catcher and site supervisor confirm that the animal and nearby habitat have been managed and the stop-work event has been recorded.

During habitat disturbance: Records and escalation

• Record the date, time, exact location, habitat feature, animal condition, identification, photographs, action taken, release or treatment location and people involved for every encounter.
• Escalate any occupied roost, repeated bat detection, mortality, injury, unauthorised clearing or damage to retained habitat to the project ecologist and environmental manager.
• Notify the relevant authority when required by the approval, permit or fauna management plan.

After habitat disturbance: Post-clearance checks

Post-clearing checks should confirm that retained roost and foraging habitat remains protected and that no bats, injuries or damaged habitat features were missed. Monitoring should be scaled to the amount of habitat removed and the sensitivity of the site.

• Inspect the cleared area, retained trees, access tracks and nearby creek-line vegetation immediately after each clearing stage.
• Check felled tree sections, hollows and fissures for animals before the material is moved, chipped or removed.
• Confirm that exclusion fencing, tree protection and no-go markers remain intact after machinery leaves the work area.
• Record retained hollow-bearing trees, damaged habitat features, animal encounters and any corrective action.

After habitat disturbance: Monitoring and reporting

Relevant movement scale: Individuals in one study moved on average less than 300 metres from roosts each night.

• Continue detector monitoring or emergence watches where a known roost was disturbed, where occupied habitat was retained beside works or where survey results were uncertain.
• Compare post-work detections with the pre-work survey using the same detector locations and comparable timing where practicable.
• Report results, incidents, injuries, mortalities, mitigation performance and database submissions to the project environmental manager and relevant approval authority.
• Maintain controls around retained habitat for the period specified in the fauna management plan or approval.

After habitat disturbance: Offsets and corrective action

• Apply any offset, restoration or compensatory habitat requirement imposed by the relevant approval or state authority.
• Investigate and correct loss of retained trees, fencing failure, sediment impacts, lighting impacts or other unplanned effects on roosting and foraging habitat.
• Review the fauna management plan if monitoring shows continuing use of work areas, repeated injury or loss of connected habitat.

Rehabilitation actions: Revegetation and habitat structure

Rehabilitation should rebuild connected forest and woodland habitat around retained roost trees, creek lines and dense understorey. It should provide future roosting structure while protecting the existing trees that bats can use immediately.

Documented habitat plants: Eucalyptus, Melaleuca, Acacia and river red gum habitats are recorded for the species.

• Replant locally appropriate eucalypts, Melaleuca, river red gum and other native species suited to the site's wet or dry forest, woodland or creek-line habitat.
• Restore dense understorey beneath and between retained trees, because the species appears to need dense understorey in tall forest to establish roosts.
• Reconnect retained forest patches with native vegetation corridors where clearing has interrupted movement between roost trees and foraging areas.
• Retain naturally forming hollows and fissures as the primary long-term roost resource.

Rehabilitation actions: Artificial features and ground protection

• Install bat boxes or other artificial roost features only where recommended by a qualified bat ecologist and approved in the fauna management plan.
• Place any artificial roost features near retained forest, dense understorey and creek-line habitat rather than in exposed isolated positions.
• Retain suitable fallen timber and natural shelter features where they do not create a fire, access or safety hazard.
• Exclude stock, vehicles and unnecessary lighting from rehabilitated habitat.

Rehabilitation actions: Threat and fire management

• Control weeds so dense native understorey can re-establish beneath retained and planted trees.
• Manage introduced predators and other site-specific threats under the approved environmental management plan.
• Use a fire management approach that protects hollow-bearing trees, dense understorey and connected forest, with timing and intensity set by the responsible land manager and relevant authority.
• Avoid unnecessary night lighting near rehabilitated habitat because artificial light may restrict foraging in urban and bushland mosaics.

Rehabilitation actions: Success monitoring

• Monitor survival and growth of plantings, understorey cover, weed control, tree protection, artificial roost use and connectivity at intervals set by the rehabilitation plan.
• Use acoustic detectors and targeted roost checks to assess whether bats continue to use retained habitat and whether activity occurs across rehabilitated areas.
• Define success measures before works, including survival of plantings, protection of retained hollow-bearing trees, stable understorey establishment, functioning connectivity and documented bat use where monitoring is required.
• Submit monitoring results and any corrective actions through the project's environmental reporting and to the relevant state wildlife database where records are suitable.

Sources

• [PDF] Feral predator and herbivore control to reduce the pressure on ..., Australian Government DCCEEW: https://www.agriculture.gov.au/sites/default/files/documents/200509.pdf
• Nyctophilus gouldi Tomes 1858, gbif.org: https://www.gbif.org/es/species/195628048
• Survey guidelines for Australia's threatened bats, Australian Government DCCEEW: https://www.agriculture.gov.au/sites/default/files/documents/survey-guidelines-bats.pdf