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New Holland Mouse (Pseudomys novaehollandiae)

The New Holland Mouse is a small, nocturnal, burrowing native rodent of fragmented heathland, heathy woodland, dry sclerophyll forest and vegetated dunes in south-eastern Australia. It is listed as Vulnerable under the EPBC Act and is highly relevant to clearing and construction projects because remaining habitat is often coastal, patchy and difficult to detect, while development, fire, predators and disease can act together to reduce local populations.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Queensland, Nature Conservation Act 1992: Vulnerable.

New South Wales, Biodiversity Conservation Act 2016: Vulnerable.

Victoria, Flora and Fauna Guarantee Act 1988: Vulnerable.

Tasmania, Threatened Species Protection Act 1995: Endangered.

Australian Capital Territory, Nature Conservation Act 2014: Vulnerable.

Breeding season

Breeding timing differs between northern and southern populations and can extend when rainfall is above average. The table gives a practical national pattern, but project controls should use local records, latitude, rainfall and recent fire history.

Month values are ordered January to December. A value of 0 means not typical, 1 means occurs or may occur, and 2 means the main or peak period. Local survey and ecological information should override this broad national pattern.

  • Breeding: Breeding is typically late winter to early spring or autumn in northern populations, and late spring to early summer in southern populations. Tasmanian guidance commonly gives August to January.
  • Young: Young are born after approximately 29 to 39 days of gestation and are suckled for 3 to 4 weeks. Dependent young may therefore occur during or shortly after the local breeding period.
  • Movement and dispersal: The species is resident rather than migratory. It is nocturnal and may move up to 206 m in one night; seasonal movement patterns have not been investigated.
  • Post-fire food and abundance peak: Abundance often peaks about 2 to 8 years after fire, depending on vegetation recovery and rainfall. This is a multi-year condition rather than a fixed month.
  • Highest clearing risk: Risk is highest during the local breeding period and while dependent young are in burrows. For southern sites, late spring to early summer is the main period; for northern sites, late winter to early spring and rainfall-supported autumn breeding may also apply.

Identification

The New Holland Mouse is a small native rodent that may be encountered during nocturnal survey, trapping or fauna handling. It can be confused with the introduced House Mouse, so positive identification should not rely on size or colour alone.

Adults have pale grey-brown fur above, white to light grey underparts and pale or pink feet with white hairs. The tail is generally longer than the head and body, darker on its upper surface and paler below, with hairs flattened against the scales. The species has relatively large eyes, a broad neck and a less pointed nose than the House Mouse.

Head and body: Approximately 65 to 90 mm.

Tail: Approximately 80 to 105 mm.

Hind foot: Approximately 20 to 22 mm.

Tasmanian ears: Approximately 12 mm, compared with about 16 mm on mainland animals.

Identification: Distinguishing it from the House Mouse

The New Holland Mouse has a bicoloured tail, larger eyes, larger rounded ears, a broader neck and a less pointed nose. It lacks the notch on the inside of the upper incisors reported for the House Mouse and does not have the distinctive mousy odour noted in field guidance.

  • Record the tail colour and hair orientation, not just tail length.
  • Check the head shape, eye and ear size, and upper incisors when the animal is safely restrained by an authorised handler.
  • Do not identify an animal from a photograph or a brief sighting as a New Holland Mouse where House Mouse confusion remains possible.
  • Use an experienced mammal ecologist or appropriate genetic or morphological confirmation for records that affect clearing decisions.

Identification: Field signs

The species is social and lives mainly in shallow underground burrows shared by several individuals. Burrow entrances, runways and disturbed sandy soil may be present in suitable heath, woodland or dune habitat, but the supplied documents do not provide a reliable diagnostic entrance size, track measurement, scat description or call.

  • Search for shallow burrows and surface runways in sandy soils with dense heath or low shrub cover.
  • Treat burrows and possible surface nests as potential fauna habitat during pre-clearing inspections.
  • Use live trapping, camera trapping, hair tubes or other approved methods where a reliable presence or absence result is required.
  • Treat a negative result cautiously because the species is patchy in time and space and survey detectability is limited.

Distribution

The New Holland Mouse has a disjunct distribution across coastal and near-coastal south-eastern Australia, with some records inland. Populations are fragmented and recent evidence indicates substantial contraction in Victoria and Tasmania.

The national range extends from southern Queensland through New South Wales, the Australian Capital Territory and Victoria to Tasmania, including Flinders Island. The species is primarily coastal, but records extend inland to about 100 km in northern New South Wales and southern Queensland, with a remnant population near Parkes more than 300 km from the coast.

  • Queensland: southern Queensland and the southern part of the broad northern population.
  • New South Wales: mid and north coasts, Jervis Bay and coastal heath systems, plus the inland Parkes population.
  • Australian Capital Territory: a reintroduced population at Mulligans Flat Woodland Sanctuary, with uncertain self-sustaining status.
  • Victoria: Anglesea and the Otways, Wilsons Promontory, Gippsland Lakes and other formerly occupied coastal sites.
  • Tasmania: north-east coast, the Freycinet and Bay of Fires areas, and Flinders Island records.

Distribution: Strongholds and subpopulations

More than 95 percent of the mapped range was assessed as a large population extending from Jervis Bay in New South Wales to north of Toowoomba in Queensland. It is likely to be highly fragmented at local scale, despite appearing relatively continuous over more than 850 km at regional scale.

Smaller, clearly isolated populations have occurred in Tasmania, Victoria and inland New South Wales. In Tasmania, recent records have been concentrated on Flinders Island after a marked decline in detections elsewhere.

Estimated extent of occurrence: Approximately 257,000 km2.

Estimated area of occupancy: Approximately 350 km2 after excluding areas burned at high or very high intensity in the 2019 to 2020 fires.

NSW and Queensland population extent: More than 850 km from Jervis Bay to north of Toowoomba.

Tasmanian detections: Search and capture data showed a contraction from 16 sites to 2 sites between 1998 and 2016, with more than a 99 percent reduction in capture per unit effort.

Victorian decline: Surveys detected the species in only 5 of 12 previously occupied areas between 2015 and 2018; the Otways recovery guidance reports failure to detect it in more than 400 camera trapping sites and more than 120 live trapping sites during 2021 to 2023.

Distribution: Population size and trend

A reliable national population estimate is not available. Monitoring shows severe local and regional declines, especially in Victoria and Tasmania, while information from the largest New South Wales and Queensland population is limited.

The species has declined through loss of occupied sites, reduced area of occupancy and reduced capture rates. It was nominated for reassessment to Endangered because of reported national reductions in captures and population size, but the material supplied here records the EPBC listing as Vulnerable.

National population estimate: Unknown.

2019 to 2020 fires: More than 45 percent of the species distribution was burned, and more than 15 percent was burned at high or very high intensity.

Severely burned areas: The Otways guidance reports an estimated 75 percent decrease in abundance in severely burned areas.

Habitat

Contemporary records are concentrated in open, floristically diverse vegetation with a heath component and sandy or friable soils. Habitat suitability varies with vegetation structure, fire succession, rainfall and local predator pressure.

Known habitat includes open and closed heathland, open woodland with a heath understorey, dry sclerophyll forest with a heath understorey, lowland forest with dense understorey, grassland in some contexts, and vegetated sand dunes. The species is associated with floristically rich vegetation, substantial mid-storey or shrub cover and relatively open lower strata with areas of bare ground.

  • Open heathlands on sandy soils.
  • Open woodlands and dry sclerophyll forests with a heath understorey.
  • Heathy woodland and lowland forest in the Otways.
  • Vegetated coastal dunes and sandy plains.
  • Potential habitat outside known occupied sites where suitable vegetation and soils remain.

Habitat: Structure and disturbance history

Abundance often increases in early to mid-successional vegetation after fire, with peaks reported from about 2 to 8 years after fire and, in some studies, 3 to 7 years. The relationship is not uniform. Recent Victorian work found that time since fire alone was a weak predictor, and the species has also persisted at some sites in older vegetation.

Typical post-fire abundance peak: Often about 2 to 8 years after fire, with 3 to 7 years reported in several studies.

Soil context: Sandy soils, sandy clay, loam, yellow duplex, friable peaty sand and granite-derived gravelly sands have been recorded.

Elevation or altitude limit: No reliable national elevation limit is provided in the supplied documents.

  • Retain a mosaic of vegetation ages rather than burning or clearing all suitable habitat at once.
  • Avoid treating a recently burned patch as the only suitable habitat, because unburnt refuges and older vegetation may support surviving animals.
  • Assess vegetation floristics, shrub structure, bare ground, soil and recent rainfall when determining habitat suitability.
  • Protect potential habitat as well as known occupied sites because detection is imperfect and occurrence can be intermittent.

Foraging habitat

The New Holland Mouse is an omnivorous food generalist that forages mainly above ground at night. It is nevertheless a habitat specialist because suitable food and cover are concentrated in particular heath and heathy woodland structures.

Seeds, especially legume seeds, form an important part of the diet. The species also eats leaves, flowers, fungi, insects and other invertebrates. Food availability is linked to rainfall and vegetation recovery after fire, which can affect breeding and survival as well as nightly foraging.

Main food: Seeds, particularly legumes.

Other food: Insects and other invertebrates, leaves, flowers and fungi.

Foraging period: Mainly at night, above ground.

  • Retain floristically diverse heath and dense understorey that can produce seeds, flowers, leaves and fungi.
  • Avoid unnecessary soil disturbance in sandy habitat, as burrowing areas and food resources occur close to the ground.
  • Manage weeds and Phytophthora because changes in plant composition can reduce food availability and understorey structure.
  • Consider increased predator exposure where clearing or fire removes ground cover around feeding areas.

Foraging habitat: Foraging area

The supplied studies provide home range estimates rather than a separate foraging distance. Radio-collared animals in Tasmania moved up to 206 m in one night and up to 37 m in one hour across a 2 ha grid. Home ranges overlapped, consistent with social use of connected habitat patches.

Maximum nightly movement recorded: Up to 206 m in one Tasmanian study.

Maximum movement in one hour recorded: Up to 37 m.

Recorded home ranges: 0.44 to 1.4 ha in Tasmania; approximately 1.39 ha for females and 2.14 ha for males at Anglesea.

  • Treat retained habitat within at least the recorded nightly movement distance of a burrow or detection point as potentially used for foraging.
  • Maintain connectivity between food patches, burrows and dense cover during staged clearing and construction.
  • Use site-specific survey results to define the area requiring protection because movement varies between locations and seasons.

Breeding habitat

Breeding is seasonal and responds to food availability, rainfall and vegetation recovery. Suitable breeding areas need connected cover, food resources and nearby burrows or surface nests.

Females can breed from about 13 weeks of age and males from about 20 weeks. Females produce one to several litters when conditions are suitable, with longer breeding seasons reported after above-average rainfall in New South Wales. In southern populations, breeding generally occurs from late spring to early summer.

Northern breeding period: Typically late winter to early spring or autumn, with extensions after above-average rainfall reported in New South Wales.

Southern breeding period: Typically late spring to early summer; Tasmania records commonly describe August to January.

Gestation: Approximately 29 to 39 days; most sources give about 32 to 39 days, while the EPBC consultation document reports 29 to 33 days.

Litter size: 1 to 6 young, with a mean of 4.6.

Female maturity: Approximately 13 weeks.

Male maturity: Approximately 20 weeks.

Lactation: Young are suckled for approximately 3 to 4 weeks.

Female lifespan: Usually up to 2 years in the wild, although third-year females have been recorded.

  • Avoid clearing, burning or intensive earthworks in occupied or potential habitat during the local breeding period.
  • Retain dense understorey, food-producing plants and shallow burrow systems near one another.
  • Plan fauna inspections and any trapping or relocation under an approved method that accounts for dependent young in burrows.

Breeding habitat: Breeding habitat features

Breeding occurs in the same broad habitat used for shelter and foraging: floristically rich heath, heathy woodland, dry sclerophyll forest with dense understorey and vegetated dunes. Food production following suitable rainfall and vegetation succession appears to influence reproductive output.

  • Retain shallow communal burrows and nearby surface cover.
  • Maintain habitat patches across several vegetation succession stages so breeding habitat is available after disturbance and during later recovery.
  • Avoid isolating small breeding groups from neighbouring cover because fragmented populations have increased risk of local extinction and reduced genetic exchange.

Sheltering habitat

The New Holland Mouse shelters mainly below ground and may remain in burrows during fire. Surface nests under low shrubs have also been recorded.

Individuals live in shallow underground burrows that are often shared with other individuals. Burrows provide daytime shelter and may help animals survive low to medium intensity fire. Surface nests beneath low-growing shrubs are an additional shelter type.

Primary refuge: Shallow underground burrows, often shared.

Other refuge: Surface nests under low-growing shrubs.

Burrow dimensions: A reliable entrance or tunnel size is not provided in the supplied documents.

Fire refuge: Burrows and unburnt vegetation patches are considered likely refuges during fire.

  • Inspect sandy or friable soils for shallow burrows before clearing, grading, trenching or vehicle access.
  • Retain low shrubs, heath cover, leaf litter and undisturbed soil around suspected burrows.
  • Do not assume that a burned patch is unoccupied because animals may survive in burrows or unburnt refuges.
  • Use an authorised fauna spotter catcher and species-appropriate trapping or exclusion method where burrows occur inside the work area.

Sheltering habitat: Construction controls

Burrow habitat can be damaged by vegetation clearing, compaction, excavation and changes to surface drainage. Small isolated shelter patches may be inadequate if surrounding foraging cover and movement routes are removed.

  • Fence and clearly mark retained habitat before machinery enters the site.
  • Keep stockpiles, spoil, access tracks and night lighting away from suspected burrows and retained heath.
  • Minimise soil compaction and avoid unnecessary removal of coarse ground cover.
  • Stage works so that animals can move towards retained habitat where this is consistent with the approved fauna management method.

Threats: Clearing and fragmentation

Threats commonly act together. Clearing can remove habitat directly, while fragmentation, fire, reduced cover, predators, disease and altered rainfall can reduce survival in the remaining patches.

Coastal development, housing, roads, agriculture, plantations and other land use changes have caused permanent habitat loss and reduced connectivity. Remaining potential habitat has high conservation value because much suitable habitat has already been cleared.

Fragmented populations are more exposed to local extinction, genetic isolation, inbreeding and failure to recolonise after fire, drought or other disturbance.

  • Avoid clearing known and potential heathland, heathy woodland, dry sclerophyll forest with heath understorey and vegetated dunes.
  • Survey before development, including habitat that appears unoccupied during a single visit.
  • Retain connected vegetation and avoid creating narrow isolated strips between roads, compounds and cleared areas.
  • Treat burrows, dense shrub patches and sandy soils as constraints during site layout and construction planning.

Threats: Fire and changed vegetation structure

Fire can create productive habitat, but fires that are too frequent, too large, too severe or poorly timed can kill animals, remove refuge and leave no suitable succession stage. Fire can also expose animals to predators by reducing ground cover. Long periods without fire may allow tea tree or other dense vegetation to replace more suitable heath structure.

  • Plan burns to retain a mosaic of recently regenerating, intermediate age and older refuge vegetation.
  • Retain unburnt refuge patches during planned burns where practicable.
  • Assess fire severity, patch size, rainfall before and after fire, vegetation recovery and predator activity rather than using time since fire alone.
  • Do not clear or burn all habitat within a local movement area in one operation.

Threats: Predators, competitors and disease

Feral Cats, European Red Foxes and Dogs can prey on nocturnal animals that spend substantial time above ground. Predation risk may increase after fire or clearing when cover is reduced. Competition with House Mice and Black Rats is possible, although the strength of this effect varies with habitat and rodent density.

Toxoplasmosis, spread by Cats, is a suspected severe threat. The supplied Otways guidance also identifies possible disease risks associated with invasive rodents.

  • Control feral Cats and Foxes around occupied sites and before any reintroduction or translocation.
  • Prevent domestic dogs and cats from entering retained habitat near works.
  • Use hygiene controls to reduce movement of Phytophthora between infected and uninfected sites.
  • Monitor House Mouse and other introduced rodent activity where food resources or construction disturbance may increase their abundance.

Threats: Disease, weeds, drought and hydrology

Phytophthora cinnamomi can simplify heath vegetation and reduce plant, fungal and invertebrate resources. Weeds and tea tree encroachment can alter understorey structure. Drought and lower rainfall reduce food availability and breeding output. The supplied documents identify changed hydrology through development as a general risk to ecological communities, but do not provide a New Holland Mouse specific hydrology threshold.

  • Keep vehicles, footwear, machinery and soil movement compliant with site hygiene procedures for Phytophthora management.
  • Prevent weed introduction and maintain floristic diversity in retained habitat.
  • Avoid drainage, groundwater or surface flow changes that dry, flood or otherwise alter sandy heath and dune habitat.
  • Schedule clearing and earthworks to avoid periods when breeding and dependent young are most likely at the site.

Survey methodology: 1. Camera trapping

The New Holland Mouse is a small, nocturnal, burrowing rodent that can be difficult to detect. Surveys should target floristically rich heathland, heath understorey, dry sclerophyll forest, open woodland, grassland and vegetated dunes, including recently burnt areas and retained patches connected to suitable habitat.

Use motion-sensor cameras as a non-invasive method where live trapping is unsuitable or where the project covers a large area.

Place cameras at burrow entrances, runways, feeding areas and ground cover within likely habitat, and sample both retained vegetation and proposed disturbance areas.

Survey during the night because the species is nocturnal and spends the day in communal underground burrows.

Use repeated deployments that cover the full proposed disturbance footprint and nearby retained habitat, because absence from a single deployment does not demonstrate absence.

Record camera model, placement, height, bait or lure if used, operating dates, effort in camera nights, habitat type, fire age, rainfall conditions and images or other evidence.

Documented broad-scale effort: Remote cameras were used at 472 sites across Victoria between 2015 and 2018.

Documented Tasmanian effort: A targeted Tasmanian survey recorded 1,268 separate visits by 22 animal species, but no definitive New Holland Mouse images.

Survey methodology: 2. Live trapping

Use live trapping where a qualified ecologist considers it necessary to confirm presence, estimate abundance or obtain animals for an approved conservation program.

Obtain the required state or territory scientific, animal ethics and wildlife handling approvals before trapping.

Set traps along likely runways, near burrows and in dense heath or understorey, with trap lines covering the range of habitat conditions within the development footprint and nearby retained areas.

Operate traps overnight because the species is nocturnal, check them at the earliest practical time each morning, protect them from exposure and release animals at the capture location unless an approved relocation plan applies.

Record trap nights, trap type, coordinates, habitat, weather, fire age, captures, non-target animals and trap-related mortality or injury.

Allow for low detection probability and population fluctuation, particularly during drought or poor food conditions.

Documented Tasmanian capture effort: Historical records include 43 captures in 790 trap nights at Hepburn Point, 4 in 150 trap nights at Friendly Beaches North, 3 in 150 trap nights at Bay of Fires and 7 in 560 trap nights at Mount William South.

Body size: Head and body length is approximately 65 to 90 mm, with a tail approximately 80 to 105 mm long.

Identification: The species has a bicoloured tail, larger eyes, a broader neck and a less pointed nose than the introduced House Mouse.

Survey methodology: 3. Hair tubes, eDNA and supplementary searches

Use hair tubes or other non-invasive sampling where live trapping is not approved or where confirmation is needed across a broad area.

Place tubes along runways, beside burrows and in suitable heath or dense understorey, and use a laboratory or suitably qualified specialist for identification.

Treat a single hair record as requiring careful verification because House Mouse hair and hair from other small mammals can be confused with New Holland Mouse hair.

Use targeted searches for burrows, surface nests, tracks, runways, feeding signs and communal shelter sites during the day, then follow up likely locations with night cameras or approved trapping.

Do not rely on spotlighting alone, because the species spends the day in burrows and is active above ground at night.

Tasmanian eDNA survey: eDNA from 287 predator scats collected in areas consistent with former habitat did not detect the species.

Burrow behaviour: Individuals generally share shallow underground burrows and may also shelter under low-growing shrubs in surface nests.

Survey methodology: Minimum effort and reporting

The supplied documents do not prescribe a single national survey effort or a project-specific number of nights, trap lines, cameras or transect kilometres for clearing projects.

Set effort using the area and quality of potential habitat, the size and connectivity of the disturbance footprint, previous records, fire history, rainfall and the detection probability of the chosen method.

Repeat surveys when conditions are unsuitable, when only weak evidence is obtained, or when the species may be patchy in time and space.

Use the best available state or territory survey guidance and obtain advice from the relevant threatened species agency before finalising the design.

  • Map all survey sites, camera nights, trap nights, hair-tube nights, search hours, transect lengths and areas surveyed.
  • Record habitat structure, dominant vegetation, understorey density, sandy or gravelly soils, burrow evidence, fire history, rainfall, temperature and disturbance history.
  • Submit verified records, including reliable negative survey results where requested, to the relevant state or territory wildlife database and the Atlas of Living Australia where appropriate.
  • Report survey limitations, detection methods, weather, effort and the basis for any conclusion about presence or absence.
  • Provide records and survey data to the Commonwealth through the project approval and threatened species reporting process when required.

Before habitat disturbance: Avoid and minimise

Avoiding habitat loss is the first control. This species uses small, fragmented patches and may be missed during surveys, so potential habitat should be treated cautiously until it has been assessed and protected through the project design.

Known range: The species occurs patchily from southern Queensland through New South Wales, the Australian Capital Territory and Victoria to Tasmania and Flinders Island.

Recorded area of occupancy: The national estimate was 350 km2 after areas burnt at high or very high intensity in the 2019 to 2020 fires were excluded.

  • Redesign the footprint to retain known records, likely burrow areas, floristically rich heath, dense heath understorey, dry sclerophyll forest with heath, open woodland with heath, grassland and vegetated dunes.
  • Retain habitat patches of different vegetation ages because abundance can increase in regenerating vegetation approximately 2 to 8 years after fire, while older or unburnt patches may provide refuge.
  • Avoid clearing habitat that provides connectivity between occupied or potentially occupied patches, particularly where populations are small or isolated.
  • Retain sandy or gravelly soils, dense ground cover, low shrubs, leaf litter, logs and other cover associated with burrows and foraging.
  • Avoid creating narrow isolated remnants, sudden edges and gaps that increase access for cats, foxes and other predators.

Before habitat disturbance: Approvals and work planning

National listing: Vulnerable under the EPBC Act, effective from 11 August 2010.

Breeding timing: Breeding is generally late winter to early spring or autumn in the north, and late spring to early summer in the south.

  • Check whether the action is likely to have a significant impact on this EPBC Act listed vulnerable species and refer the action to the Australian Government where required.
  • Check the current state or territory listing, permit, survey, trapping, handling, relocation and animal ethics requirements before work starts.
  • Prepare a fauna management plan that identifies habitat, survey results, exclusion areas, clearing limits, fauna handling arrangements, stop-work triggers and reporting responsibilities.
  • Plan staged clearing so that suitable habitat is retained while the project team confirms that animals have moved or have been safely handled.
  • Schedule vegetation removal outside periods of drought, extreme heat and other conditions that reduce food availability or increase stress, where the project program allows.
  • Coordinate fire planning with the species response to vegetation succession, rather than applying a uniform fire interval across the site.

Before habitat disturbance: Site preparation

  • Complete a pre-clearance survey using methods suited to the site and document all potential habitat, burrows, runways, surface nests and recent records.
  • Mark no-go areas, retained vegetation, habitat corridors, burrow clusters and any approved access routes before machinery enters the site.
  • Install exclusion fencing where it can prevent entry into retained habitat or direct animals away from the work area without trapping them against the fence.
  • Brief machinery operators and spotter catchers on the species' appearance, nocturnal activity, burrowing behaviour and the difference between it and the House Mouse.
  • Keep cats and dogs out of the work area and require all contractors to report sightings immediately.
  • Clean machinery and footwear where Phytophthora cinnamomi is a risk, using the project's approved hygiene and wash-down procedures.

During habitat disturbance: Daily controls and machinery interface

Clearance should be slow, staged and supervised. The fauna spotter catcher should have authority to pause machinery whenever a New Holland Mouse, burrow cluster or unexpected suitable habitat is found.

Activity period: The species is nocturnal and forages above ground at night.

Movement: Recorded home ranges include approximately 0.44 to 1.4 ha in Tasmania and approximately 1.39 ha for females and 2.14 ha for males at Anglesea.

  • Inspect exclusion fencing, gates, retained habitat and access routes before work begins each day.
  • Use a qualified fauna spotter catcher in front of clearing machinery and maintain direct communication with the operator.
  • Clear from the disturbed edge towards retained habitat where this is safe and appropriate, leaving animals an escape route into protected vegetation.
  • Remove vegetation in short stages and pause between stages to allow animals to move from exposed cover.
  • Do not allow machinery to enter marked retained habitat, burrow areas or habitat corridors.
  • Stop work during extreme heat, heavy rain, fire, smoke or other conditions that make searching or handling unsafe.

During habitat disturbance: Habitat features and animals

Size and weight: Individuals are approximately 65 to 90 mm in head and body length and weigh approximately 12 to 20 g in Queensland and New South Wales, 18 to 25 g in Victoria and 19 to 28 g in Tasmania.

Social behaviour: The species commonly lives in shared underground burrows.

  • Inspect shallow burrows, surface nests, dense shrubs, logs, litter, rock cover and other ground shelter before removing or disturbing them.
  • Do not excavate or collapse burrows until the fauna spotter catcher has inspected the area and the approved fauna management plan allows the work.
  • Leave logs, rocks, litter and low shrubs in retained habitat wherever practicable because they provide shelter and foraging structure.
  • If a burrow or shelter must be removed, use hand tools and staged removal under the direction of the fauna spotter catcher.
  • Do not handle a New Holland Mouse unless the person is authorised, trained and operating under the relevant permit and animal welfare requirements.
  • Place a captured animal in a clean, secure, appropriately ventilated container with suitable bedding and keep handling time as short as possible.
  • Release an unharmed animal into nearby retained habitat only where this is authorised and the release site is suitable, connected and outside the work area.
  • Do not move animals across roads, cleared gaps, fire breaks or unsuitable habitat, and do not mix animals from different populations without an approved conservation translocation plan.

During habitat disturbance: Incidents, stop work and records

  • Stop work immediately if a New Holland Mouse is found, if an occupied or potentially occupied burrow is exposed, or if clearing enters an unassessed patch of suitable habitat.
  • Notify the project ecologist, environmental officer and relevant approval authority according to the fauna management plan.
  • Place injured animals in a quiet, secure container and transfer them promptly to an authorised wildlife carer or veterinarian, following the permit and animal welfare requirements.
  • Do not provide food, water, medication or treatment unless directed by a veterinarian or authorised wildlife carer.
  • Record the date, time, coordinates, habitat, activity, animal condition, photographs, identification method, handling time, release or treatment location and names of authorised personnel.
  • Record all dead, injured, trapped or relocated fauna and report notifiable incidents under the project approval.

After habitat disturbance: Checks and monitoring

Post-clearance work should confirm that animals have not been left in isolated fragments and that retained habitat, fencing and restoration areas remain functional.

Rainfall response: At Anglesea, abundance was positively related to cumulative monthly residual rainfall with a 0 to 9 month lag.

Fire response: Population peaks have been recorded approximately 2 to 8 years after fire, although the response varies with vegetation recovery, rainfall, fire severity and patch pattern.

  • Complete a systematic post-clearance inspection of the work area, retained edges, access tracks, exclusion fencing and any remaining burrow or shelter areas.
  • Repeat camera, hair-tube or approved live-trapping surveys where an animal was detected, where habitat was partly cleared or where the approval requires post-clearance monitoring.
  • Monitor retained patches and corridors for changes in ground cover, weed invasion, Phytophthora symptoms, cat and fox activity, fire impacts and House Mouse abundance.
  • Monitor during suitable seasons and after rainfall as well as during dry periods, because rainfall affects food availability, breeding and population abundance.
  • Use the same locations and methods where possible so that changes in occupancy and detection can be compared over time.

After habitat disturbance: Reporting and controls

Fragmentation risk: Small isolated populations are more vulnerable to local extinction, stochastic events, genetic isolation and inbreeding.

  • Maintain exclusion fencing, gates, signage and retained habitat controls until the environmental officer confirms that the risk from construction has ended.
  • Report clearance areas, retained habitat areas, survey effort, incidents, animal outcomes and monitoring results to the approval holder and relevant government agencies.
  • Submit verified records to the relevant state or territory wildlife database and update project spatial data when new locations are found.
  • Review the fauna management plan after each incident, unexpected record, failed relocation or change in construction method.
  • Apply offsets or other approved conservation measures where residual impacts remain after avoidance and mitigation.

Rehabilitation actions: Restore habitat structure

Rehabilitation should restore connected, structurally diverse habitat rather than only planting trees. The target is habitat that provides dense understorey, food plants, burrowing soils and shelter across several vegetation succession stages.

Habitat types: Known habitat includes open heathlands, open woodlands with heath understorey, dry sclerophyll forests with heath understorey, grasslands and vegetated sand dunes.

Diet: The diet includes seeds, particularly legumes, as well as insects, other invertebrates, leaves, flowers and fungi.

  • Re-establish locally appropriate open heathland, open woodland with heath understorey, dry sclerophyll forest with heath, grassland or vegetated dune structure according to the pre-disturbance community.
  • Use locally appropriate native species that provide floristically diverse understorey, seeds, leaves, flowers, fungi and invertebrate habitat.
  • Retain or reinstate low shrubs, ground cover, leaf litter, fallen timber, rocks and other shelter features without creating piles that provide den sites or hunting cover for cats and foxes.
  • Restore sandy, friable or gravelly soil conditions suitable for shallow burrows and avoid compaction in rehabilitation areas.
  • Provide connected vegetation between retained habitat patches and avoid narrow plantings that do not provide cover at ground level.
  • Use nest boxes only where monitoring demonstrates a need for supplementary shelter, because the species generally uses underground burrows rather than tree hollows.

Rehabilitation actions: Manage weeds, disease, predators and fire

Fire and habitat: The species often increases in early to mid-successional vegetation, but recent Victorian evidence found that time since fire alone is not a reliable predictor of habitat suitability.

Key threats: Recognised threats include inappropriate fire, clearing, weeds, Phytophthora cinnamomi, cats, foxes, introduced rodents, toxoplasmosis, drought and climate change.

  • Control weeds and prevent dense tea-tree or other invasive plant cover from replacing the diverse understorey used by the species.
  • Use Phytophthora hygiene controls during soil movement, planting, weed control and maintenance, and assess whether phosphite or other approved treatments are suitable.
  • Control feral cats and foxes around rehabilitation and release areas, particularly after fire or clearing has reduced ground cover.
  • Manage House Mouse and other introduced rodent risks where monitoring shows competition, predator support or disease concerns.
  • Develop a site-specific fire plan that maintains a mosaic of vegetation ages and avoids burning the entire connected habitat at one time.
  • Protect unburnt refuge patches and consider the intensity, scale, season and interval of burns rather than relying only on time since fire.

Rehabilitation actions: Measure success

Generation length: Approximately 1 to 2 years.

Reproduction: Females mature at approximately 13 weeks, gestation is approximately 29 to 39 days and litters contain 1 to 6 young.

  • Set measurable targets for native plant cover, understorey structure, weed cover, soil condition, connectivity, predator activity and survival of planted vegetation.
  • Use repeat cameras, hair tubes and approved live trapping to measure occupancy, breeding evidence, abundance and use of restored habitat.
  • Monitor for at least the period required by the approval and continue through dry and wet conditions so that rainfall-driven population changes are detected.
  • Treat successful rehabilitation as habitat that is used by New Holland Mice over repeated surveys, not simply as an area that has been planted.
  • Use adaptive management when monitoring shows poor recruitment, predator activity, Phytophthora spread, excessive fire intensity or loss of understorey.

Sources