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Heath Monitor (Varanus rosenbergi)

The Heath Monitor is a large, terrestrial goanna of southern Australia. It uses heathland, open woodland and sclerophyll forest, with shelter sites, fallen timber, dense ground cover and termite mounds being important habitat features. Clearing, removal of ground habitat, grazing, inappropriate fire, roads and disturbance of termite mounds are key issues on development sites.

Conservation status

New South Wales, Biodiversity Conservation Act 2016: Vulnerable.

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

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

Breeding season

Heath Monitors mate in summer, lay eggs in terrestrial termite mounds, and retain eggs through the cooler months. Clearing can harm adults, eggs and hatchlings from late summer through spring, while adults and juveniles may shelter in burrows, rocks, logs and mounds during winter.

Reproductive mode: Egg laying in terrestrial termite mounds.

Clutch size: Usually up to 13 or 14 eggs; reported range 3 to 19 eggs.

Incubation: About 6 to 8 months, usually around 7 months. One source reports the first sign of hatching approximately 8 months after laying.

Size at hatching: Approximately 21 to 25 cm long and 17 to 21 g.

Age at maturity: About 3 years; another source records first breeding at 18 to 36 months.

Nest or egg sites: Egg chambers excavated inside active terrestrial termite mounds, reported at about 700 mm deep in one source.

Breeding frequency: Females often have a 1 to 2 year break between breeding attempts and seldom breed in consecutive years.

Confirm timing locally before works, especially where rainfall and temperature alter termite activity, mound conditions, winter torpor or the timing of hatchling emergence.

  • Mating: Mating is reported in January, with courtship beginning near the longest day and lasting 4 to 6 weeks. The timing may extend from December into February across the species range.
  • Gravid females: Females carry developing eggs between summer mating and laying about three weeks after the last mating. The documented reproductive sequence places this period mainly in January to March.
  • Egg laying: Eggs are laid in active termite mounds in summer. Sources place mating in January and nest excavation or laying mainly from February to March, with laying occurring in the late afternoon or at night.
  • Incubation: Eggs remain sealed inside termite mounds for about 6 to 8 months, usually around 7 months. They remain in the mound through winter and may be present until September or October when laid in February or March.
  • Hatchlings: Young emerge mainly in September and October, when outside temperatures increase. They can remain in the mound for several days and continue using it as shelter for up to four to five months.
  • Active period: The species is active year round in temperate southern Australia, but activity is restricted in winter. Activity areas are larger in summer and smaller in spring and autumn, and adults are generally day active.
  • Winter inactivity: In southern and cooler parts of the range, low activity and torpor are most relevant in June to August. Animals may remain near burrows or shelter in burrows, rocks, logs and other thermal refuges, although they can arouse and bask during suitable weather.
  • Highest clearing risk: Risk is highest from February to October because termite mounds may contain newly laid eggs, developing embryos or hatchlings, and adults or juveniles may be sheltering during winter. Treat clearing as a year round risk because mounds, burrows, rocks, logs, litter and dense ground cover can be damaged in any month.

Identification

The Heath Monitor is a large, fast-moving goanna with a dark, finely spotted body and a strongly banded tail. It is mainly terrestrial and may be encountered crossing tracks, roads or open heath.

Adults are blackish or dark grey above, with fine yellow or white spotting and paired blackish bands from the neck along the body. The belly is whitish and marked with black or grey reticulation. The limbs are dark with cream to pale yellow spots.

The tail is laterally compressed and has narrow, regular dark and pale bands extending to the tip. The tail pattern helps separate the Heath Monitor from the Lace Monitor, which has broader light and dark bands towards the tail tip and an unbanded tail tip.

Total length: Up to 1.5 m

Body pattern: Fine yellow or white spotting with paired dark bands

Tail: Laterally compressed, with narrow bands continuing to the tip

Identification: Field signs

Inspect terrestrial termite mounds in suitable habitat. Used mounds may have holes of a characteristic shape and size at the base, made by adults entering and newly hatched young leaving.

Other useful signs include burrows, occupied or recently used rocky fissures, and observations of goannas basking on logs in open areas. Road-killed goannas should be checked and recorded where the species occurs.

  • Search around termite mounds for basal entry and exit holes.
  • Inspect burrows, rocks, hollow logs and dense ground vegetation without dismantling potential refuges.
  • Record road-killed goannas and retain photographs or location data for identification.

Identification: Sexes and other observations

The supplied sources do not provide reliable field characters for separating males and females. They also do not describe diagnostic calls, scats, sloughs or eyeshine.

Distribution: National range

The Heath Monitor occurs in southern Australia, with separated populations in the south-west and south-east. Its distribution is patchy, and the source material identifies distinct northern and southern populations in New South Wales.

The species is recorded from Western Australia, South Australia, Victoria, New South Wales and the Australian Capital Territory. In Western Australia it occurs in the far south-west, including areas north and south of the Swan River. In South Australia it occurs in the southern part of the state.

In Victoria, populations are isolated and may be rare or locally common. In New South Wales, the documented range includes coastal areas, including Sydney sandstone country.

States and territory: Western Australia, South Australia, Victoria, New South Wales and the Australian Capital Territory

Bioregional pattern: Far south-western and southern Australia, coastal New South Wales and Sydney sandstone country

Distribution: Subpopulations and strongholds

The New South Wales review identified two disjunct populations. Northern monitors occur on Sydney sandstone rocky outcrops and escarpments. Southern monitors occur in woodlands on poor, infertile soils.

Northern sites may have stronger protection because much of their potential range is reserved. Persistence of southern populations depends on management across both public and non-reserve land.

Distribution: Population size and trend

The supplied sources do not provide a national population estimate or a quantified population trend. A habitat target in the north-east disturbance assessment used an estimated density of 0.002 animals per hectare for one habitat quality category, with a calculated target area of 188,982 hectares. This is a planning estimate, not a national abundance estimate.

Modelled density: 0.002 animals per hectare in the cited habitat quality category

Modelled target area: 188,982 hectares in the cited planning unit

Habitat: Habitat types

Heath Monitors use open, dry or humid terrestrial habitats with a well-developed ground layer and access to rocks, logs, burrows and termite mounds.

Recorded habitat includes sandy heathland, coastal heath, open woodland, humid woodland, and wet and dry sclerophyll forest. The New South Wales review also identifies Sydney sandstone rocky outcrops and escarpments, and woodlands on poor, infertile soils.

Suitable habitat may occur in reserves, state forests, private land and development areas. Habitat outside reserves needs management because clearing and fragmentation can separate populations and remove ground features.

Habitat: Structural features

Important habitat elements include termite mounds, rocky outcrops, rock fissures, hollow logs, burrows, dense ground-layer vegetation and logs used for basking. Ground litter and understorey structure are particularly important where grazing or burning can remove cover.

  • Retain termite mounds and a surrounding buffer of undisturbed ground habitat.
  • Retain rocks, hollow logs, fallen timber, burrows and dense ground vegetation.
  • Maintain connected habitat containing shelter sites between cleared areas.

Habitat: Elevation and climate

The sources do not specify an elevation limit. The species is associated with southern Australian coastal and temperate habitats, including humid and dry sclerophyll forests, heathland and open woodland.

Foraging habitat: Diet

The Heath Monitor is an active, opportunistic carnivore that searches terrestrial habitat for both live prey and carrion.

Recorded food includes reptiles, insects, birds, mammals, eggs and carrion. The species can pursue relatively large prey and is described as an opportunistic generalist.

Trophic level: Estimated trophic level 1 in the disturbance assessment

Foraging habitat: Foraging sites and behaviour

Foraging habitat includes heathland, open woodland and wet or dry sclerophyll forest. The supplied sources do not provide a measured foraging range, daily movement distance or named food plants.

Retain connected ground habitat, logs, rocks and dense vegetation because these features support prey availability, movement and cover while the monitor searches for food.

  • Avoid clearing connected ground habitat between shelter sites.
  • Retain fallen timber, litter and dense understorey where safe to do so.
  • Do not remove termite mounds or other ground structures that may provide prey or shelter.

Breeding habitat: Breeding biology

Breeding is closely associated with terrestrial termite mounds. Females lay eggs in or use termite constructions, where the developing young receive warmth and regulated humidity.

The female lays eggs and leaves them in a burrow or termite mound for incubation. The sources describe termite mounds as providing favourable warmth and humidity when outside conditions are unsuitable.

The timing of mating and egg laying, age at maturity, incubation duration and hatching period are not specified in the supplied sources.

Breeding season: Not specified in the supplied sources

Clutch size: Up to 14 eggs

Incubation: Eggs are left in a burrow or termite mound; duration is not specified

Age at maturity: Not specified

Lifespan: Not specified. Estimated reproductive longevity is 1 to 11 years, mean 5 years

Breeding habitat: Breeding habitat features

Breeding habitat is Sydney sandstone woodland or heathland containing suitable terrestrial termitaria. In practical terms, retain termite mounds, their basal entrances and the surrounding ground cover.

The New South Wales survey guidance recommends searching for termite mounds in appropriate seasons and developing prescriptions to protect them.

  • Mark and protect termite mounds before clearing or construction.
  • Do not collapse, excavate, fill or isolate mounds from surrounding ground habitat.
  • Inspect the base of mounds for characteristic adult entry and juvenile exit holes.

Sheltering habitat: Refuges

Heath Monitors use a range of ground-level and rocky refuges. The supplied sources do not give standard refuge dimensions.

Known shelter sites include burrows, hollow rocks, rocky fissures, rock outcrops, hollow logs and dense ground-layer vegetation. Hollow trees are also reported as refuge sites.

Logs in open areas provide basking sites. Retain basking logs where they do not create a safety hazard.

Refuge size: No standard dimensions are provided

  • Retain burrows, rocky fissures, hollow rocks, hollow logs and dense ground cover.
  • Inspect potential refuges before earthworks and avoid dismantling them during clearing.
  • Maintain nearby basking logs and open patches where practicable.

Sheltering habitat: Ground habitat

Grazing can reduce the ground cover needed by termites to build mounds. Grazing and associated burning can also remove litter and alter understorey structure, reducing shelter and movement cover for monitors.

Firewood collection and removal of fallen timber can reduce available refuge sites. Ground habitat should therefore be retained within and between development impact areas.

  • Keep leaf litter, fallen timber, rocks and dense low vegetation in retained habitat.
  • Prevent stock access where grazing would remove ground cover or damage termite mounds.
  • Avoid using retained shelter features as spoil storage, access tracks or construction compounds.

Threats: Clearing and fragmentation

The main project risks are removal of ground habitat and termite mounds, fragmentation, grazing, fire, roads and introduced predators. Risk can remain even where canopy vegetation is retained.

Clearing for urban development was ranked as a disturbance for the species. Sand extraction and other mining can remove heathland, woodland, rocky features, termite mounds and connected ground habitat.

The New South Wales review states that cross-tenure management is needed because the species has a broad range and some important habitat occurs outside reserves.

  • Survey potential habitat before clearing, including rocks, hollow logs, burrows, dense ground cover and termite mounds.
  • Retain connected habitat rather than isolated vegetation remnants wherever practicable.
  • Protect termite mounds and nearby ground habitat from direct and indirect construction impacts.

Threats: Fire, grazing and ground habitat loss

Any fire was ranked as a high disturbance for the species in the north-east assessment. Grazing and associated burning were also ranked highly because they can remove litter and change understorey structure.

Fuel management burns may benefit Heath Monitors where they encourage heath regeneration, but inappropriate frequency, intensity, season or spatial arrangement can remove litter and shelter. Fire planning should therefore account for retained mounds, logs, rocks and ground cover.

  • Do not burn retained habitat without a site-specific fire assessment.
  • Avoid fire regimes that repeatedly remove litter, logs or dense ground cover.
  • Manage grazing to retain the cover needed by termites and monitors.

Threats: Predators and roads

Foxes and other introduced predators can prey on eggs and juvenile monitors. Adults may also be exposed to non-target effects of fox baiting.

Roadkill was ranked as a disturbance for the species. New roads, widened roads and construction traffic can increase mortality and divide habitat.

  • Use fauna-sensitive traffic controls where roads cross known or potential habitat.
  • Record and report road-killed goannas during construction monitoring.
  • Plan predator control with advice on non-target risks to adult monitors and other reptiles.

Threats: Hydrology and disease

The supplied sources do not identify a specific disease or a quantified hydrological threat for the Heath Monitor. Projects should nevertheless avoid changing drainage, waterlogging or soil conditions around termite mounds, burrows and retained ground habitat without assessment.

Survey methodology: 1. Desktop and habitat assessment

Survey this species by searching its distinctive shelter and breeding features, rather than relying on a single detection method. The available guideline is for pre-logging and pre-roading surveys, so apply its search principles to the project footprint, access tracks and a 50 metre adjoining area where works may affect habitat.

Review records, aerial imagery, geology, vegetation and proposed disturbance before entering the site.

Map sandy heathland, open woodland, dry or wet sclerophyll forest, rocky outcrops, rock crevices, hollow logs, dense ground vegetation, burrows and terrestrial termite mounds.

Treat habitat as potentially suitable where several shelter features occur together, even if no recent record is available.

Survey methodology: 2. Compartment traverse and feature search

Use an experienced reptile surveyor to traverse the disturbance footprint and the adjoining 50 metres where access and safety allow.

Search continuously for at least 4 hours per 200 hectares, as specified for the pre-logging compartment traverse.

Inspect suitable microhabitat, including burrows, the underside of rocks, fallen logs and dense ground-layer vegetation.

Search for termite mounds during an appropriate season. Look for mounds with holes of the characteristic shape and size associated with adult entry and juvenile emergence.

Record every suitable feature, occupied feature, observation, track, burrow, mound and road-killed goanna with a GPS location and photograph.

Minimum traverse effort: 4 hours per 200 hectares

Search area in the guideline: Net logging area and within 50 metres of its boundary

Features to inspect: Burrows, rocks, fallen logs, dense ground vegetation and termite mounds

Survey methodology: 3. Targeted searches and detection

Conduct targeted fauna searches in known or potential habitat within the project footprint and the adjoining 50 metres where disturbance could extend beyond the footprint.

Have all personnel who work in the species' geographic range familiar with its identification before surveys or clearing begin.

Examine road-killed goannas where safe and lawful, and submit photographs or specimens through the relevant authority process when identification is uncertain.

Use additional active searches, remote cameras or other methods only where the project ecologist considers them suitable for the habitat and access constraints. The supplied guideline does not provide a standard spotlighting, trapping or camera effort for this species.

Survey methodology: Minimum effort and reporting

  • Use the 4 hour per 200 hectare traverse as the minimum documented feature-search effort where the project is comparable to the guideline's pre-logging survey setting.
  • Document the area searched, hours, dates, weather, surveyors, access limitations, habitat features inspected, termite mound searches and all results.
  • Explain any reduction in the 4 hour per 200 hectare effort and obtain written approval from the project ecologist or regulator before clearing.
  • Submit confirmed records, including accurate coordinates, photographs and evidence, to the relevant state wildlife database and advise the relevant land manager or wildlife authority.
  • Update the assessment if taxonomy, state listing or survey requirements change before works commence.

Before habitat disturbance: Avoid and minimise

Avoid removing the features that the heath monitor uses for shelter, basking, movement and breeding. The species has disjunct northern and southern populations, so project controls must protect both individual sites and connections between retained habitat patches.

Retain terrestrial termite mounds, rocky outcrops, rock crevices, hollow logs, fallen timber, burrows and dense ground-layer vegetation.

Retain sandy heathland, open woodland and sclerophyll forest where these features occur together.

Keep retained habitat connected with adjoining vegetation and avoid creating isolated patches separated by cleared ground.

Avoid removing leaf litter and ground cover, particularly where grazing, machinery or associated burning would expose the soil.

Avoid sand extraction, unnecessary firewood collection and clearing of rocky or log-rich habitat.

Before habitat disturbance: Approvals and project controls

Confirm the current Commonwealth and state conservation status before works, because the supplied material identifies state listings but does not establish a Commonwealth listing for the project date.

Check whether the proposal needs a Commonwealth referral, state approval, threatened species permit, wildlife handling authority or separate approval for clearing native vegetation.

Prepare a fauna management plan that maps habitat features, exclusion zones, pre-clearance methods, spotter catcher roles, stop-work triggers, relocation decisions and reporting requirements.

Schedule clearing outside periods identified by the project ecologist as unsuitable for safe detection, and complete termite mound searches in an appropriate season.

Before habitat disturbance: Site preparation

Complete the pre-clearance traverse and targeted feature search before finalising the clearing boundary.

Mark termite mounds, burrows, rock features, hollow logs, dense ground cover and retained habitat on plans and in the field.

Fence or otherwise exclude retained habitat and marked features where machinery could enter them, provided the fencing will not trap an animal or block required movement.

Brief machine operators and supervisors on the species' appearance, habitat features, exclusion areas and stop-work procedure.

Confirm a nearby retained release area before any relocation is authorised.

During habitat disturbance: Daily controls and machinery interface

Use a controlled clearing sequence that gives the animal a chance to leave retained habitat and allows the fauna spotter catcher to inspect features before they are disturbed. Stop work whenever the approved controls cannot be maintained.

Hold a daily pre-start briefing covering the mapped features, exclusion zones, weather, access routes and the day's clearing sequence.

Use a fauna spotter catcher who can direct the operator, inspect the next area and stop machinery immediately when a fauna risk is identified.

Clear progressively towards retained habitat, where safe, so animals are not surrounded by machinery or cut off from shelter.

Keep machinery outside marked exclusion zones unless the fauna spotter catcher and environmental officer approve entry under the fauna management plan.

Do not burn, bury, chip or remove logs, rocks, termite mounds or ground cover until they have been inspected and the applicable approval allows the action.

During habitat disturbance: Habitat feature handling

Do not disturb a termite mound until the ecologist has assessed whether it is active or likely to be used for breeding.

Inspect rocks, hollow logs, burrows and dense ground cover immediately before disturbance and again after relocation or removal of the feature.

Retain suitable logs, rocks and ground cover in the retained area wherever practicable, and avoid placing them where they block drainage or create a machinery hazard.

Avoid unnecessary disturbance to wetlands and riparian areas, even though the supplied species material does not provide a wetland-specific habitat prescription.

Do not remove hollow trees or other shelter features without a documented assessment of their fauna risk and the required approval.

During habitat disturbance: If a heath monitor is found

Stop nearby machinery and keep people, vehicles and dogs away from the animal.

Allow the animal to move to retained habitat if it can do so safely; do not chase it or handle it simply to clear the work area.

Only a person authorised under the applicable wildlife approval and trained in reptile handling may capture, restrain or relocate the animal.

If relocation is approved, release it into nearby suitable retained habitat with rocks, hollow logs, dense ground vegetation or burrows, following the fauna management plan and regulator directions.

Place an injured animal in a secure, ventilated container appropriate for a large monitor and arrange prompt assessment by an authorised wildlife carer or veterinarian.

Record the location, time, condition, photographs, action taken, release location, personnel and approval reference.

During habitat disturbance: Stop-work triggers and records

  • Stop work if a heath monitor, occupied termite mound, burrow or other mapped feature is found inside the active work area and the approved response has not been confirmed.
  • Stop work if exclusion fencing is damaged, the spotter catcher loses sight of the work face, or machinery must enter an unassessed habitat area.
  • Stop work after an injury, mortality, repeated animal escape toward machinery or failure of the approved relocation process, and notify the environmental officer.
  • Maintain daily records of cleared area, machinery movements, weather, searches, features affected, animal observations, incidents, relocations and photographs.
  • Notify the regulator and project approval holder within the time required by the approval for any threatened fauna injury, death, unapproved feature disturbance or control failure.

After habitat disturbance: Post-clearance inspection

Post-clearance work should confirm that no animal or habitat feature was missed and that retained habitat remains usable. Keep fauna controls in place while construction continues to affect access, shelter or movement.

Have the fauna spotter catcher or ecologist inspect the cleared area, retained edges, access tracks, stockpiles and any disturbed termite mounds, logs, rocks or burrows before the next work stage.

Check for live animals, carcasses, tracks, fresh burrow use and damage to marked habitat features.

Repair exclusion fencing and reinstate approved habitat features where machinery has displaced them.

Report any new detection or mortality through the approval process and to the relevant state wildlife database where a record is appropriate.

After habitat disturbance: Monitoring and reporting

Monitor retained habitat for continued ground cover, shelter features, termite mound condition and connectivity during construction and rehabilitation.

Use the monitoring method, duration and triggers specified in the fauna management plan or approval; the supplied documents do not provide a post-construction monitoring duration for this species.

Compare monitoring results with the pre-clearance feature map and document changes in habitat condition.

Provide the client, approval holder and relevant regulator with survey effort, records, incidents, relocations, mortality, corrective actions and photographs.

After habitat disturbance: Ongoing controls and offsets

Maintain exclusion zones, access controls and weed and predator controls for as long as construction could disturb retained habitat.

Manage any offset, restoration area or conservation covenant in accordance with the approval and its conditions.

Give priority to retaining and managing habitat on all relevant tenures, because the review states that off-reserve management is needed for persistence of southern populations.

Rehabilitation actions: Restore habitat structure

Rehabilitation should rebuild the dry, open and structurally varied ground habitat used by heath monitors. Retention and reinstatement of natural shelter and termite mound habitat are more directly supported by the supplied documents than a prescribed planting list.

Re-establish locally appropriate sandy heath, open woodland or sclerophyll forest vegetation consistent with the pre-disturbance community.

Use locally appropriate native species selected by the restoration ecologist for the site's soil, drainage and vegetation community; the supplied documents do not name a planting list for this species.

Reinstate leaf litter, low ground vegetation, fallen timber, hollow logs, rocks and suitable burrow opportunities without importing contaminated soil or pest species.

Protect existing termite mounds and allow termite colonies and mound structure to recover naturally; do not construct artificial mounds unless a qualified ecologist and regulator approve the method.

Keep rehabilitation areas connected to retained habitat and avoid planting dense vegetation that removes open basking areas where open structure is part of the local habitat.

Rehabilitation actions: Fire, weeds and predators

Prepare a fire plan that considers frequency, season, intensity and the spatial pattern of burns, because the review states that fire can benefit some habitats but harm other species and that an appropriate regime should be set for threatened species.

Do not burn rehabilitation areas until the project ecologist and fire authority have assessed leaf litter, termite mounds, ground cover and shelter requirements.

Control weeds that reduce heath and ground-layer habitat, using methods that do not damage termite mounds, logs, rocks or retained fauna.

Control foxes and other introduced predators under an approved program, while assessing non-target risks to adult monitors and other native fauna.

Prevent grazing from removing ground cover needed around termite mounds and shelter features.

Rehabilitation actions: Monitoring and success measures

Inspect rehabilitation after establishment and after major disturbance events for native ground cover, retained or reinstated logs and rocks, functioning burrows, intact termite mounds and links to retained habitat.

Use photo points, fixed transects and mapped feature checks to measure change against the pre-clearance condition.

Record heath monitor sightings, tracks, burrow use, roadkill and evidence of termite mound use, and submit confirmed records to the relevant state wildlife database.

Set project-specific completion criteria for vegetation establishment, ground cover, shelter features, weed cover, predator control and connectivity before rehabilitation begins.

Continue corrective works where erosion, grazing, weeds, fire or predator activity prevents the habitat from meeting the approved criteria.

Sources