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Bassian Thrush (Zoothera lunulata)

The Bassian Thrush is a secretive, ground-foraging forest bird found mainly in damp, densely vegetated habitats across south-eastern Australia, with an isolated population in north-east Queensland. The South Australian subspecies, Western Bassian Thrush, is listed as Endangered under the EPBC Act and can be affected by clearing, fire, hydrology changes and loss of dense understorey on development sites.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Breeding season

Timing varies across Australia. The pattern below combines the South Australian subspecies with broader species records. May to November is the main breeding period cited for South Australia, while breeding from June to February has been reported for the species more broadly.

Months are January to December. A value of 1 means the activity occurs or risk is present; 2 would indicate a peak period. No peak value is assigned where the supplied documents do not support one.

  • Breeding: South Australian birds breed from May to November. The broader species account gives June to February, with April also recorded, so regional timing should be checked before clearing.
  • Young: Nestlings remain in the nest for about 14 days and both parents feed the young. Dependent young may remain associated with dense cover after leaving the nest, but the supplied sources do not give a longer dependency period.
  • Movement and dispersal: The species is mostly sedentary, with some seasonal movement, particularly altitudinal movement. The South Australian subspecies is considered largely sedentary, so clearing should not rely on a migration-free season.
  • Song and detection: In north-east New South Wales, Bassian Thrush songs were detected most often from October to December and were not detected in February or March during the cited study. Dawn, dusk and dull weather are useful detection periods.
  • Highest clearing risk: Risk is highest from May to November in South Australia because breeding, nests and young may be present. The broader species breeding period extends to February, so February clearing can also affect breeding birds in some regions.

Identification

Bassian Thrushes are cryptic forest birds that are more often detected by their movement or song than by prolonged views. Their mottled plumage blends with leaf litter, and a disturbed bird may run a short distance and freeze.

Adults are olive-brown to mottled brown above, with black crescent-shaped barring on the head, back and rump. The underparts are pale with brown-black scalloping, and a narrow white eye-ring is present. The bill is large and straight with a slight hook at the tip, while the legs are long and strong.

In flight, look for the broad dark diagonal bar across the white underside of the wing. The bird usually moves low through dense vegetation or runs across the forest floor before freezing or taking cover.

Length: 25 to 30 cm in the South Australian conservation advice; 27 to 29 cm in the Australian Museum account.

Mass: Around 100 g in the South Australian conservation advice; approximately 120 to 130 g in the species account.

Identification: Similar species

The Bassian Thrush can resemble the Russet-tailed Thrush, Zoothera heinei. The Russet-tailed Thrush is generally more rufous above and has a longer tail. In north-east New South Wales, Bassian Thrushes were recorded mainly at 900 to 1100 m, while Russet-tailed Thrushes were recorded mainly at 300 to 700 m, although elevation alone is not a reliable identification feature.

  • Use the wing pattern, strong scalloping, white eye-ring, bill shape and song together rather than relying on plumage colour alone.
  • The sexes are similar in appearance.

Identification: Field signs and calls

The song is a quiet, melodic sequence of two or three whistles. It is most often heard around dawn, during short periods at dusk, or in dull weather. In a north-east New South Wales study, Bassian Thrush songs were detected most often from October to December.

Nests are large, deep or bowl-shaped structures made from moss, bark, grass, leaves, fine twigs and roots. They are usually placed in a tree fork, but may also occur on a thick horizontal branch, stump, natural cavity, behind loose bark or on a tree-fern crown. No diagnostic tracks, scats, sloughs or eyeshine features are described in the supplied sources.

Nest height: Near ground level to about 15 m above ground.

Nest contents: Usually 2 to 3 eggs; both parents feed the young.

  • Treat an unfamiliar low whistle or a brief, soft contact call from dense forest as a possible detection and investigate without flushing the bird.
  • Use targeted acoustic recording where visual searches are unlikely to detect this secretive species.

Distribution: National range

The species occurs across much of eastern and south-eastern Australia, with the South Australian subspecies restricted to South Australia. Records and population estimates are uneven, so absence from a short survey does not demonstrate absence from suitable forest habitat.

Bassian Thrushes occur in south-eastern Australia, including South Australia, Victoria, New South Wales and Tasmania, and in north-east Queensland, including the Atherton Tablelands. The species also occurs on islands in south-eastern Australia, including Kangaroo Island and other islands within the broader south-eastern range.

The supplied sources do not assign the species to formal IBRA bioregions. The named regions that support the South Australian subspecies are Kangaroo Island, the Fleurieu Peninsula, the Mount Lofty Ranges and the southern Flinders Ranges. In north-east New South Wales, records come from the Border Ranges and Mebbin National Parks.

Distribution: South Australian strongholds

The Western Bassian Thrush occurs on Kangaroo Island, the adjacent mainland, the Fleurieu Peninsula, the Mount Lofty Ranges and the southern Flinders Ranges. On Kangaroo Island it has been associated particularly with damp gullies in the western half of the island.

The mainland and Kangaroo Island birds are considered likely to form one subpopulation, and the South Australian subspecies has been considered panmictic despite gaps or barriers between Kangaroo Island, the Fleurieu Peninsula, the Mount Lofty Ranges and the Flinders Ranges.

Distribution: Population and trend

The South Australian subspecies has undergone a severe decline, driven mainly by the 2019 to 2020 Kangaroo Island bushfires. Detection rates remained low in burnt areas after the fires, and no individuals were detected in completely burnt vegetation during the cited surveys.

In the Mount Lofty Ranges, acoustic monitoring in 2021 detected birds at 26 of 60 sites. Detections occurred at 2 of 21 northern sites, 11 of 23 central sites and 13 of 16 southern sites.

Estimated mature population, South Australian subspecies: About 3,300 individuals, with a declining trend.

Extent of occurrence, South Australian subspecies: Approximately 14,000 km² and contracting.

Area of occupancy, South Australian subspecies: Approximately 510 km² and contracting.

Fire impact on distribution: About 39% of the distribution was burnt at high to very high severity, with a further 9% burnt at low to moderate severity in the 2019 to 2020 fires.

Kangaroo Island habitat affected: About 85% of suitable habitat was estimated to have been burnt.

Habitat: Vegetation and structure

Bassian Thrushes use damp, densely vegetated forest and woodland with a closed or thick canopy, dense lower vegetation and substantial leaf litter. In South Australia, suitable habitat is often restricted to creek lines, damp gullies and dune swales.

Preferred habitat is damp eucalypt forest or woodland with a thick canopy, a dense understorey of small trees and tall shrubs, and leaf litter on the ground. Mature mallee eucalypt woodland is also used on Kangaroo Island, and breeding has been recorded in exotic Monterey Pine plantations.

Retain connected patches of dense vegetation, creekline vegetation, damp swales, fallen woody material and intact leaf litter. Roadside vegetation corridors may provide habitat and movement routes, including after fire.

  • Inspect damp gullies, creek lines, swales, dense forest margins and partly burnt forest before clearing.
  • Avoid removing intact understorey or leaf litter where it forms part of a suitable forest patch, even if the canopy is partly open.
  • Treat unburnt vegetation within or beside recently burnt areas as potential refuge habitat.

Habitat: Climate and elevation

Damp conditions appear important, particularly during summer. Drying of moist gullies can reduce habitat suitability. In north-east New South Wales, Bassian Thrushes were recorded mainly at 900 to 1100 m, with earlier work recording them from about 550 to 1100 m.

The species also occupies lower elevation damp forests elsewhere in its range, so the north-east New South Wales elevation pattern should not be applied as a national limit.

Documented elevation pattern in north-east New South Wales: Most detections were at 900 to 1100 m; earlier records extended from about 550 to 1100 m.

Important wet features: Damp gullies, creek lines, dune swales and other areas that retain moist leaf litter.

Foraging habitat: Food and foraging method

Bassian Thrushes forage mainly on the ground, probing and scratching through damp leaf litter. They may forage alone or in small groups of two to five, and may take fruit from low shrubs.

The diet consists mainly of earthworms, beetles and other invertebrates, with occasional fruit. Birds probe or scratch through leaf litter and may take fruit from low shrubs.

Foraging habitat is usually beneath dense forest or woodland cover, especially where the ground remains damp and leaf litter is intact. Damp habitats may be particularly important in summer.

Main prey: Earthworms, beetles and other invertebrates.

Other food: Occasional fruit, including fruit taken from low shrubs.

Typical group size: Single birds or small groups of two to five, possibly family groups.

  • Keep leaf litter, soil surface structure, fallen woody material and dense low vegetation intact in suitable habitat.
  • Avoid prolonged activity, vehicle movement and soil disturbance in damp forest patches during the breeding season and other periods when birds are using the ground to forage.
  • Search quietly along creek lines, damp gullies, swales and the edges of dense understorey rather than relying only on canopy observations.

Foraging habitat: Foraging range and territory

The supplied sources do not provide a measured home range, territory diameter or daily foraging distance. Birds are probably territorial and are mostly sedentary, so habitat removal within a small forest patch may affect an individual or pair even when the broader area remains vegetated.

  • Do not infer that a site is unimportant because only one bird is detected during a brief search.
  • Use repeated observations or acoustic monitoring to assess use of adjoining habitat where clearing may divide a dense forest patch.

Breeding habitat: Nest habitat

Breeding requires dense vegetation for concealment and a suitable fork, branch, stump, cavity or other elevated support for the nest. Both parents care for the young.

The nest is usually placed in a tree fork or occasionally on a thick horizontal branch. Other reported sites include a stump, natural cavity, behind loose bark and the crown of a tree fern. Dense foliage conceals the nest, and nest height can range from near ground level to about 15 m.

Breeding has been recorded in damp eucalypt forest and woodland, mature mallee woodland on Kangaroo Island and Monterey Pine plantations. Retaining dense foliage and potential nest supports is therefore important even where the vegetation is not wholly native.

  • Inspect trees, stumps, dense shrubs and tree-fern crowns within or beside proposed clearing for nests before works begin.
  • Establish a no-go area around an active nest and obtain project-specific fauna advice before modifying vegetation or access around it.
  • Schedule clearing outside the main breeding period where practicable, particularly in known or suitable habitat.

Breeding habitat: Breeding facts

Breeding season, South Australian subspecies: May to November.

Breeding season, species-wide accounts: June to February, with breeding also recorded in April; regional timing varies.

Clutch size: Usually 2 to 3 eggs.

Incubation: About 14 days.

Time in nest: About 14 days.

Age at first reproduction: About 1.8 years, according to the supplied species account.

Parental care: Both parents feed the young.

Generation length: Estimated at 3.9 years for the South Australian subspecies.

Lifespan: An average age of 3.9 years and a maximum age of about 7.6 years are reported in the supplied species account; these figures should not be treated as a direct field ageing method.

Sheltering habitat: Ground and foliage cover

The species shelters by remaining still in leaf litter or dense foliage, rather than using a specialised den or hollow. Unburnt and partly burnt dense vegetation can provide cover after fire.

When disturbed, a Bassian Thrush may run a short distance and freeze, relying on camouflage against leaf litter. It may also take refuge in a shrub or bush with thick foliage. Dense understorey, leaf litter and low vegetation therefore provide both daytime concealment and escape cover.

The species has a low, secretive flight and generally stays beneath or within dense forest vegetation. Open, recently burnt ground is less likely to provide suitable cover than intact or partly burnt forest.

  • Keep dense ground cover and leaf litter intact around retained forest patches and creeklines.
  • Do not assume that a quiet, apparently empty patch is unused if it contains damp leaf litter and dense cover.
  • Protect unburnt refuges within or beside burnt areas from additional clearing or prescribed fire until surrounding habitat has recovered.

Sheltering habitat: Roosts and nest supports

No separate roost structure, hollow requirement or burrow is described in the supplied sources. Nest support can be provided by tree forks, thick horizontal branches, stumps, natural cavities, loose bark and tree-fern crowns, from near ground level to about 15 m.

Known shelter features: Leaf litter, dense shrubs, thick understorey and unburnt or partly burnt forest cover.

Known nest-support height: Near ground level to about 15 m.

  • Retain trees with forks, thick branches, loose bark, cavities and dense foliage where they occur in suitable habitat.
  • Include stumps and tree-fern crowns in pre-clearing nest inspections.

Threats: Clearing and fragmentation

The main development risks are removal or degradation of damp forest, dense understorey and leaf litter, altered water flows, inappropriate fire and disturbance of refuge habitat. The South Australian subspecies has already suffered a severe decline after extensive fire on Kangaroo Island.

Historical land clearance for agriculture and forestry has removed habitat across the range. Further clearing can reduce area of occupancy, remove foraging and breeding habitat, and break up movement routes between forest patches.

Roadside vegetation corridors can provide habitat and dispersal routes. Their removal, including for road widening, vegetation offsets or fire management, may therefore increase fragmentation.

  • Avoid clearing known occupied habitat and suitable future habitat, including areas currently unoccupied after fire but capable of regeneration.
  • Map damp gullies, creeklines, swales, dense understorey and partly burnt vegetation before finalising the clearing footprint.
  • Assess adjoining and cumulative clearing rather than treating each small patch in isolation.

Threats: Fire and fire management

Frequent or intense fire can alter vegetation structure, reduce leaf litter and woody debris, increase weeds and reduce invertebrate abundance. Several fires in close succession can delay recolonisation, particularly in fragmented habitat.

The 2019 to 2020 Kangaroo Island fires burnt about half the island and an estimated 85% of suitable habitat for the South Australian subspecies. No individuals were detected in completely burnt vegetation during the cited post-fire surveys, although birds used some partly burnt sites.

South Australian distribution affected by 2019 to 2020 fires: About 48% was burnt when high to very high and low to moderate severity fire are combined.

Mount Lofty Ranges habitat affected by cited fires: About 10% of suitable habitat was burnt by the Cudlee Creek fire.

  • Protect unburnt patches within or beside recently burnt areas from additional prescribed fire and unnecessary vegetation removal.
  • Include threatened species locations and suitable habitat in wildfire prevention, suppression and recovery planning.
  • Avoid assuming that a burnt site has no conservation value, because it may recover and may be needed for future recolonisation.

Threats: Hydrology, grazing and weeds

Reduced natural water flow caused by dams, water use and interception can dry downstream habitat. Up to 80% of water flows in the Adelaide and Mount Lofty Ranges region have been diverted, affecting downstream ecosystems.

Livestock and other herbivores can graze, trample and compact the ground layer. Weeds can alter vegetation structure and increase fuel loads. Phytophthora cinnamomi may cause plant dieback and reduce habitat suitability.

  • Maintain natural flow regimes and avoid dams or works that reduce water availability to damp gullies, creeklines or swales.
  • Fence or otherwise exclude stock from sensitive ground cover where grazing or trampling is occurring.
  • Use hygiene controls to reduce the risk of spreading Phytophthora cinnamomi and soil-borne weeds between sites.

Threats: Predators, competition and roads

Feral cats and European Red Foxes are identified predators on the mainland, while cats threaten birds on Kangaroo Island. Common Brushtail Possums may take nests or eggs on Kangaroo Island. Competition with introduced Common Blackbirds is considered possible but is less well understood.

The supplied documents do not provide evidence of road mortality as a specific threat. Roads can still affect the species where road construction removes roadside habitat, creekline vegetation or movement corridors.

  • Control feral predators where they are identified as a significant risk, particularly in fire-affected habitat.
  • Manage food, waste and shelter around worksites so they do not increase access by feral predators.
  • Treat road widening, access tracks and drainage works as potential habitat loss where they remove dense roadside or creekline vegetation.

Survey methodology: 1. Automated acoustic recording

Bassian Thrushes are secretive, ground-foraging birds of damp, densely vegetated forest, woodland and gullies. Surveys should combine automated acoustic detection with targeted searches of leaf litter, creek lines, damp gullies and other retained habitat. The supplied documents do not provide a statutory survey guideline or a prescribed minimum effort for project assessments, so the methods below are a practical species-based approach.

Deploy automated acoustic recorders in suitable habitat, especially damp gullies, creek lines, creekline vegetation, mallee swales and densely vegetated forest with a thick canopy and leaf litter.

Use the documented study design as a practical reference: record five 2-minute periods each day, starting 10 minutes before sunrise, with each period separated by a 10-minute delay.

Repeat recording across the likely breeding and non-breeding periods where practicable. Bassian Thrush song activity is often highest around dawn, and birds may also call in dull or overcast weather.

Review recordings for the species' soft, melodic whistles and other calls. Contact calls alone may not reliably separate Bassian Thrush from Russet-tailed Thrush.

Exclude or flag recordings affected by heavy rain, strong wind or other high background noise, and document the number of unusable recordings.

Use acoustic monitoring for cryptic birds that may be missed by visual searches. A published study processed 5,825 two-minute recordings and detected Bassian Thrush songs in 239 recordings across 20 sites.

Documented acoustic schedule: Five 2-minute recordings per day, beginning 10 minutes before sunrise, with 10-minute intervals

Published study duration: 12 months, from June 2015 to May 2016

Published study design: 20 sites across five elevation bands, approximately 300, 500, 700, 900 and 1,100 metres

Published detections: Bassian Thrush song detected in 239 of 5,825 processed recordings

Survey methodology: 2. Dawn and daytime habitat searches

Search on foot through retained damp forest, woodland and gullies, concentrating on thick understorey, dense canopy, creek lines, damp leaf litter and sheltered areas.

Conduct searches from before sunrise through the early morning, when the species is most likely to sing or move through the understorey.

Walk quietly and slowly, scanning the ground, low shrubs, tree forks and dense foliage. A disturbed bird may run briefly and then freeze, relying on its mottled plumage for camouflage.

Record all observations, calls, feeding signs, nest sites and movement routes, including the habitat condition and the distance from the proposed disturbance footprint.

Treat apparently unused burnt habitat as potentially important where it may recover. The conservation advice identifies suitable habitat that is currently unoccupied after fire as habitat critical to survival if it may become suitable again.

Body length: 25 to 30 cm

Typical body mass: Around 100 g

Foraging: Mostly on the ground, probing damp leaf litter for earthworms and beetles

Breeding period in South Australian conservation advice: May to November

Survey methodology: 3. Targeted habitat and occupancy assessment

Map all damp eucalypt forest and woodland, dense gullies, creek lines, mallee swales, wet leaf-litter areas, mature mallee woodland and connected roadside or riparian vegetation within and adjoining the work area.

Assess habitat on both sides of the disturbance footprint because the species is mostly sedentary but may make seasonal or local movements, including altitudinal movements.

Inspect retained vegetation for dense canopy, tall shrubs, small trees, leaf litter, woody debris and sheltered ground-feeding areas.

Survey likely refuge habitat as well as the footprint. On Kangaroo Island, partly burnt sites have been used, while no individuals were detected in completely burnt vegetation in the cited surveys.

Where the species cannot be confidently excluded, use repeat acoustic monitoring or seek advice from the relevant state environment agency before clearing.

Known western Bassian Thrush range: Kangaroo Island, adjacent South Australian mainland, the Mount Lofty Ranges and southern Flinders Ranges

Published South Australian population information: Around 300 to 500 birds in the Fleurieu Peninsula and Mount Lofty Ranges, and possibly around 100 in the southern Flinders Ranges

Known habitat feature: Suitable habitat is often confined to creek lines or dune swales

Survey methodology: Minimum effort and reporting

  • Use more than one detection method where suitable habitat is present, with automated acoustic recording and targeted dawn searches forming the minimum practical combination for a project assessment.
  • Record the survey dates, start and finish times, weather, wind, rainfall, recorder locations, recording schedule, search routes, observer names, detection method and all negative results.
  • Submit confirmed records, including reliable acoustic records, photographs and coordinates, to the relevant state or territory wildlife database and the Atlas of Living Australia where appropriate.
  • Report the taxon precisely. Confirm whether a record is Bassian Thrush, Russet-tailed Thrush or the western Bassian Thrush subspecies before using it to assess an EPBC matter.
  • Retain original sound files, photographs, field notes and spatial data with the project environmental records.
  • If a survey is intended to support an EPBC assessment or approval, confirm the current department survey expectations and obtain advice from the relevant regulator before fieldwork begins.

Before habitat disturbance: Avoid and minimise habitat loss

Plan the project around retention of damp, densely vegetated habitat and safe movement between retained areas. The western Bassian Thrush conservation advice treats all known occupied areas and suitable habitat within the known range as potentially critical to survival.

  • Avoid clearing occupied habitat, damp gullies, creekline vegetation, mallee swales, dense understorey and connected roadside vegetation wherever practicable.
  • Retain mature canopy, understorey, leaf litter, woody debris and damp ground conditions used for foraging, shelter and breeding.
  • Retain unburnt or partly burnt vegetation adjacent to burnt areas, because these areas may provide refuge and may support recolonisation as burnt habitat regenerates.
  • Avoid changes to natural water flow, including drainage, dam construction, diversion, pumping and sediment movement that could dry or degrade damp habitat.
  • Maintain vegetated links between retained habitat patches and avoid isolating small remnants.
  • Do not introduce weeds, pathogens, predators or other fauna between the mainland and Kangaroo Island.

Before habitat disturbance: Approvals and timing

  • Check the current EPBC Act listing and determine whether the affected taxon is the listed western Bassian Thrush subspecies, Zoothera lunulata halmaturina, rather than an unlisted population of another subspecies.
  • Refer the action under the EPBC Act if the project is likely to have a significant impact on the listed taxon or its habitat.
  • Check state and territory threatened species legislation, wildlife permits, clearing controls, fauna handling requirements and park or reserve approvals before work starts.
  • Confirm whether a fauna spotter catcher, wildlife carer, veterinarian or other authorised person is required under the relevant jurisdiction.
  • Schedule clearing outside the main breeding period where practicable. In the South Australian conservation advice, breeding is described as May to November, while general species information gives June to February, so use the applicable regional advice and avoid active nests at all times.
  • Stage works so that retained habitat and refuge areas remain available while adjoining areas are cleared or regenerated.

Before habitat disturbance: Pre-clearance planning

  • Complete a targeted pre-clearance survey immediately before works, with attention to ground-foraging birds, nests, dense foliage, tree forks, logs, leaf litter and damp refuge areas.
  • Mark no-go areas, habitat to be retained, access routes, exclusion zones and any known detection locations before machinery enters the site.
  • Prepare a fauna management plan that sets out survey methods, stop-work triggers, authorised personnel, capture and release procedures, injury response, contact details and reporting requirements.
  • Use exclusion fencing where it can safely prevent machinery or workers entering retained habitat, but do not create barriers that trap birds or sever access to retained vegetation.
  • Brief all workers on the species' cryptic behaviour, likely habitat, reporting procedure and the requirement to stop work if a bird or active nest is found.

During habitat disturbance: Daily site controls

Clearance should be slow, supervised and staged. The fauna spotter catcher should direct machinery away from retained habitat, inspect each work area and stop operations when a bird, nest or unexpected habitat feature is found.

  • Inspect exclusion fencing, no-go markers, access routes and retained habitat before work begins each day.
  • Use a fauna spotter catcher or other authorised wildlife professional where required by the approval or jurisdiction.
  • Clear in stages towards retained habitat or other safe refuge, allowing birds to move away without being driven into roads, machinery or open areas.
  • Keep machinery, vehicles, spoil, lighting and workers out of retained gullies, creek lines, damp leaf litter and marked refuge areas.
  • Avoid unnecessary removal of leaf litter, woody debris, understorey and fallen timber from retained habitat.
  • Suspend work during high wind, heavy rain, smoke or other conditions that prevent safe detection and handling.

During habitat disturbance: Working with machinery

  • Require the fauna spotter catcher to inspect the next work section before machinery enters it and to remain able to communicate directly with the operator.
  • Use small work sections and pause machinery regularly so the spotter catcher can check dense foliage, ground cover, tree forks, logs and other refuge features.
  • Stop machinery immediately when the spotter catcher gives the agreed stop signal or when a Bassian Thrush, nest, injured animal or unexpected habitat feature is found.
  • Do not chase a bird through dense vegetation or force it into open ground, roads or active work areas.
  • Record the location and condition of any habitat that is retained, damaged or unintentionally removed.

During habitat disturbance: Animal encounters and habitat features

  • Do not catch, handle or relocate a Bassian Thrush unless the person is authorised under the relevant state or territory requirements and the action is necessary for its welfare or project compliance.
  • Allow an uninjured bird to leave naturally where it can move safely into nearby retained habitat.
  • If capture is required, use the least invasive method available and release the bird as soon as practicable into suitable nearby retained habitat, following the approved fauna management plan and agency advice.
  • Do not relocate a bird across roads, into exposed burnt areas, into unsuitable dry vegetation or outside its local area without specific approval and expert advice.
  • Treat active nests, tree forks, dense foliage, logs, rocks, burrows, wet areas and substantial leaf-litter patches as potential fauna features and inspect them before removal or disturbance.
  • If an injured bird is found, place it in a secure, quiet container only if authorised and safe to do so, and contact a veterinarian or licensed wildlife carer immediately.
  • Do not handle eggs, chicks or an active nest unless directed by the relevant wildlife authority or an appropriately authorised person.

During habitat disturbance: Stop-work triggers and records

  • Stop work in the affected section if a Bassian Thrush is found within the disturbance area, an active nest is identified, an animal is injured, or approved exclusion controls fail.
  • Keep the affected area undisturbed until the fauna spotter catcher and project environmental officer decide on the next action under the fauna management plan.
  • Notify the project environmental officer and regulator where required by the approval, particularly for a listed western Bassian Thrush subspecies or repeated detections.
  • Record species, number of individuals, exact location, habitat condition, time, action taken, release location, injuries, photographs and the names and authorisations of people involved.
  • Retain all fauna incident forms, acoustic files, photographs and daily pre-start records with the project compliance records.

After habitat disturbance: Post-clearance checks

Post-clearance work must confirm that no animal or habitat feature was missed and that retained habitat remains usable. Monitoring should focus on occupancy, habitat condition, fire impacts, water availability and threats identified for the local population.

  • Inspect the cleared area and its margins for injured, trapped or displaced birds after each work stage and again before the area is signed off.
  • Check retained gullies, creeklines, dense understorey, leaf litter and refuge areas for damage, sediment, altered drainage, weeds, stock access and machinery intrusion.
  • Remove temporary hazards such as open pits, unsecured pipes, exposed wire, netting and waste that could trap ground-foraging birds.
  • Confirm that all approved no-go areas, fencing, drainage controls and habitat markers remain in place.

After habitat disturbance: Monitoring and adaptive management

  • Repeat acoustic monitoring at retained habitat where the project may have affected occupancy, using the same recorder locations and schedule where practicable so results can be compared.
  • Monitor sites affected by fire, clearing or altered water flow to assess whether habitat remains suitable and whether birds return as vegetation and leaf litter recover.
  • Investigate any decline in detections, loss of damp ground conditions, increased predator activity, weed spread or damage to retained habitat, and change project controls where needed.
  • Continue monitoring for the period required by the approval, environmental management plan or regulator.

After habitat disturbance: Reporting and ongoing controls

  • Submit required EPBC, state and project reports, including survey results, clearance areas, fauna incidents, relocations, injuries, deaths, habitat retained and rehabilitation progress.
  • Update the relevant state wildlife database with confirmed records and submit reliable records to the Atlas of Living Australia where appropriate.
  • Maintain predator, grazing, weed, pathogen, fire and water-flow controls for the period specified in the approval or management plan.
  • Provide offset proposals where approved habitat critical to survival cannot be avoided or mitigated, in accordance with the applicable regulatory decision.

Rehabilitation actions: Restore habitat structure

Rehabilitation should restore damp, structurally complex habitat rather than only planting canopy trees. The objective is to provide connected ground-foraging habitat with dense cover, leaf litter, stable moisture and safe breeding sites.

  • Replant locally indigenous eucalypt forest or woodland species and understorey plants suited to the local soil, rainfall, creekline or gully environment.
  • Restore a dense canopy, small trees, tall shrubs and ground cover, because the species uses densely forested areas with thick canopy, understorey and leaf litter.
  • Reinstate leaf litter and retain naturally fallen timber and woody debris where safe, because the species forages among damp leaf litter and fire can reduce woody debris and invertebrate abundance.
  • Re-establish vegetated links between retained habitat patches, creeklines, gullies, swales and adjacent regeneration areas.
  • Protect regenerating vegetation from grazing, trampling, vehicle access and unnecessary slashing.

Rehabilitation actions: Water, weeds, pests and fire

  • Restore natural drainage and avoid designs that divert, intercept or rapidly drain water from damp gullies, creeklines and swales.
  • Control weeds that alter habitat structure or increase fuel loads, using methods that minimise disturbance to leaf litter and native regeneration.
  • Control feral cats and foxes where they are identified as a significant local threat, particularly in habitat affected by fire or disturbance.
  • Manage grazing and trampling by livestock, kangaroos, feral pigs, deer, rabbits, goats and other herbivores where they damage regenerating habitat.
  • Plan fire prevention and response to protect retained refuge areas and recently regenerating habitat from unnecessary prescribed burning, mechanical removal and fire suppression impacts.
  • Use site-specific fire planning that reduces the risk of frequent, large or high-intensity fire while allowing for the ecological needs of the local vegetation.

Rehabilitation actions: Nest and refuge features

Natural nest placement: Usually in a tree fork or occasionally on a thick horizontal branch, from near ground level to about 15 metres above ground

Typical clutch: Two to three eggs

Parental care: Both parents feed the young

  • Retain suitable mature trees, tree forks, dense foliage and other natural structures that may support the species' bowl-shaped nests.
  • Where approved habitat design identifies a shortage of suitable nest sites, consider nest boxes or other artificial structures only after advice from the relevant state agency or an experienced ornithologist.
  • Do not remove logs, rocks, dense shrubs or damp leaf-litter patches from rehabilitation areas unless required for safety or approved works.
  • Locate any artificial nest structures in retained or regenerating habitat with suitable canopy and understorey, and inspect them under an approved monitoring plan.

Rehabilitation actions: Monitoring and success measures

  • Monitor revegetation survival, canopy and understorey development, ground cover, leaf-litter depth, moisture, weed cover, grazing damage, predator activity and fire impacts.
  • Use repeat dawn searches and automated acoustic recorders to assess whether Bassian Thrushes use rehabilitated and adjoining retained habitat.
  • Compare detections with suitable reference sites where available, while recognising that the species is secretive and absence from a single survey does not prove absence.
  • Set success measures around establishment of connected damp woodland or forest, retention of leaf litter and understorey, stable water conditions, effective threat controls and documented bird use over time.
  • Continue monitoring until the rehabilitation area provides suitable foraging and shelter habitat and the project approval requirements have been met.

Sources