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Slender-billed Thornbill (Acanthiza iredalei)

The Slender-billed Thornbill is a small, mostly sedentary insectivorous bird of chenopod shrublands, saltmarsh and low heath in southern Australia. It is listed as Vulnerable under the EPBC Act, and suitable shrubland can be removed or damaged by clearing, development, altered hydrology, grazing, fire and coastal change. On development sites, dense samphire, saltbush or bluebush within 20 metres of tidal channels or saline lakes should be treated as potential habitat.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Victoria, Flora and Fauna Guarantee Act 1988: Endangered.

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

Breeding season

Timing varies with rainfall and subspecies, but breeding generally occurs from winter into spring. The highest risk from vegetation clearing is during breeding and the period when fledged young remain dependent in or near the nesting habitat.

Month values are ordered January to December. A value of 0 means not typical, 1 means occurs, and 2 means peak or highest risk.

  • Breeding: Breeding is usually recorded from July to October and may follow rainfall. Western Australian records include July to September.
  • Nesting and young in nest: Nests and active breeding evidence were recorded from late August to early September in 2024. The species lays two to four eggs, with both parents feeding hatchlings.
  • Fledglings and dependent young: Fledged young were recorded from 12 September onwards in the 2024 Gulf St Vincent survey. Young may shelter in dune vegetation and adjacent shrubland after leaving the nest.
  • Movement and group formation: The species is probably sedentary, but groups may be larger outside the breeding season. Young may move into adjacent dune shrubland and other habitat after fledging.
  • Highest clearing risk: Clearing can remove habitat at any time, but July to October presents the greatest risk of destroying nests, eggs, nestlings or dependent fledglings. Confirm breeding status before clearing during this period.

Identification

This is a small, olive-grey to brown thornbill with a fine bill and a distinctive black forehead patch edged in white. It is easily overlooked in dense low shrubland because it is quiet, shy and often remains inside vegetation.

Adults are about 10 cm long, have a 14 to 15 cm wingspan and weigh 5 to 6 g. The plumage is olive-grey or olive-brown, with pale underparts and a black forehead patch with white edging. The tail is blackish with paler tips.

Birds are usually encountered in pairs or small groups. Groups commonly contain up to 10 birds in the South Australian fact sheet, while flocks of 20 to 30 birds are reported outside the breeding season and groups of up to 60 have occasionally been recorded.

Body length: About 10 cm.

Wingspan: 14 to 15 cm.

Weight: 5 to 6 g.

Identification: Similar species

The western subspecies may be mistaken for the Western Thornbill, Acanthiza inornata. The supplied survey guideline states that their current ranges do not overlap, so location and habitat are important parts of identification.

The Samphire Thornbill of the upper Gulf St Vincent is described as the darker form, with olive-grey plumage, a buff rump, grey-white underparts and olive-buff flanks.

Identification: Calls, nests and field signs

The species is quiet and inconspicuous. It is most readily detected by listening for its calls and may respond to playback, particularly during the breeding season. Visual searches should focus on birds moving through dense shrubs, birds flushed from vegetation and pairs carrying food or nesting material.

Nests are dome-shaped, have a side entrance and are built from strips of bark, dry seagrass, twigs, grass and spider web or spider egg sacs. They are lined with feathers or other soft material and are usually placed less than 1 metre above the ground, commonly at about 0.5 to 1 metre.

Typical nest height: Less than 1 metre above ground, commonly 0.5 to 1 metre.

  • Look for small thornbills moving quietly through dense chenopod shrubs.
  • Listen for calls during early morning searches.
  • Check dense shrubs for dome-shaped nests with a side entrance.
  • Treat adults carrying food or nesting material, and fledglings giving distinctive squeaks, as evidence of breeding nearby.

Distribution

The species has three subspecies occupying different low-shrub habitats in southern Australia. Records are concentrated in southern Western Australia, South Australia and north-western Victoria, with the Gulf St Vincent subspecies restricted to coastal saltmarsh around the upper Gulf St Vincent.

The western subspecies, Acanthiza iredalei iredalei, occurs in arid and semi-arid southern Western Australia and south-western South Australia. It is associated with saltbush, bluebush, samphire and related chenopod shrublands, including shrublands around salt lakes and salt flats.

Acanthiza iredalei hedleyi occurs in heath habitats of the upper south-east of South Australia and north-western Victoria. Acanthiza iredalei rosinae, also called the Samphire Thornbill or Gulf St Vincent subspecies, occurs in coastal saltmarsh around the upper Gulf St Vincent.

  • Western Australia: southern and south-western arid and semi-arid shrublands.
  • South Australia: south-western shrublands, Eyre Peninsula and coastal saltmarshes around the Gulf St Vincent, with records also in the upper south-east.
  • Victoria: north-western Victoria, mainly associated with the range of the heathland subspecies.

Distribution: Known strongholds and subpopulations

The upper Gulf St Vincent population is concentrated in coastal saltmarsh from the Barker Inlet around the head of the gulf and south to Price. The 2024 survey covered 19 sites at 12 locations and recorded the subspecies at 17 sites.

Recorded locations included Torrens Island, St Kilda, Buckland Park, Port Gawler, Middle Beach, Lower Light, Baker Creek, Bald Hill Beach, Port Wakefield, Clinton Conservation Park, Wills Creek Conservation Park and Price Saltfields.

2024 Gulf St Vincent survey: 620 individuals, including 61 fledged young, were recorded over 11 survey days.

2024 survey coverage: 19 sites across 12 locations.

Sites with detections: 17 of 19 sites.

Highest 2024 site counts: Middle Beach recorded 100 individuals and Lower Light recorded 93 individuals.

Local density: At Clinton, density estimates were 2.9 to 8.4 birds per hectare of suitable samphire habitat, or 1.5 to 4.3 birds per hectare when unsuitable areas were included.

Distribution: Population information

The South Australian fact sheet estimates that around 100,000 individuals remain in the wild, but the document does not make clear whether this estimate applies to the western subspecies alone or to the species as a whole.

The 2024 Gulf St Vincent survey recorded many birds and breeding activity but was not designed to provide a repeatable population estimate. The report states that no meaningful inference about overall population trends can be made from that survey.

Habitat

Slender-billed Thornbills occupy low, dense shrublands in arid, semi-arid and coastal saline environments. Habitat condition and shrub structure are more useful field indicators than broad vegetation class alone.

The western subspecies primarily uses chenopod shrublands associated with salt lakes, salt flats and saline drainage areas. It has also been recorded in mangrove-fringed samphire shrublands, other low shrublands and low heath on sand plains.

The Gulf St Vincent subspecies uses coastal samphire saltmarsh, particularly dense Shrubby Samphire, Tecticornia arbuscula. It also occurs in mixed samphire, saltbush, bluebush and adjacent dune or shellgrit shrubland.

  • Shrubby Samphire, Tecticornia arbuscula.
  • Other Tecticornia and Sarcocornia saltmarsh.
  • Saltbush, Atriplex spp.
  • Bluebush, Maireana spp.
  • Low heath on sand plains.
  • Dune and shellgrit shrubland adjoining saltmarsh.

Habitat: Key habitat structure

The best documented Gulf St Vincent habitat consists of one to three metre tall Shrubby Samphire with a Beaded Glasswort, Sarcocornia quinqueflora, understorey. Birds are densest in shrubs within 10 to 20 metres of tidal channels, saline lakes, drainage lines, mudflats or ephemeral ponds.

Dense, divaricate shrubs provide cover, nest sites and perches. The birds can also use drier shrubland away from saltmarsh, particularly after breeding when fledglings shelter and forage in adjacent vegetation.

  • Retain dense shrub patches rather than isolated individual plants only.
  • Map shrubs within 20 metres of tidal channels, saline lakes and drainage lines as higher suitability habitat.
  • Include adjoining dune, shellgrit and low shrubland when assessing habitat affected by clearing.
  • Record shrub height, density, dieback and distance to water or saline drainage features.

Habitat: Climate and elevation

The species is associated with arid and semi-arid parts of southern Australia and with coastal microclimates around Gulf St Vincent. The supplied documents do not provide a reliable elevation range.

Elevation: Not stated in the supplied documents.

Foraging habitat

The Slender-billed Thornbill feeds through the day, mainly within low shrubs and occasionally on the ground or in the air. It often forages close to nesting cover and uses several plant layers around saltmarsh edges.

The diet consists mainly of insects and other small invertebrates, including flies, fly larvae, beetles, spiders, caterpillars and occasionally centipedes. The birds also take seeds, plant material and insects associated with plant flowers and galls.

In Gulf St Vincent saltmarsh, birds glean prey from Tecticornia arbuscula and other Tecticornia, Tecticornia halocnemoides, Nitre Bush, Nitraria billardierei, and White Mangrove, Avicennia marina. Samphire gall insects may be an important food source.

Main food: Small flies, fly larvae, beetles, spiders, caterpillars and other invertebrates.

Additional food: Seeds and other plant material.

Foraging habitat: Foraging behaviour

Birds glean prey from foliage, twigs and the ground surface. They may hawk small moths and other flying insects from a shrub perch, returning to the same or another perch. They may also forage on mud surfaces and around mangrove flowers.

Most observations indicate short-distance movements. In the Clinton area, most recaptures were within 100 metres of the original capture point, and the furthest reported resighting was 650 metres by a young bird.

Typical recapture distance: Most recaptures were within 100 metres.

Furthest reported resighting: 650 metres, involving a young bird.

Reported home range: Less than 25 hectares.

  • Search foliage and the ground beneath dense chenopod shrubs for foraging birds.
  • Inspect samphire with galls, flowering mangroves and Nitre Bush near shrubland edges.
  • Treat adjacent mudflats, tidal channels and dune shrubland as part of the foraging area where birds are present.
  • Avoid assuming that open mudflat or low saltmarsh is unused, as birds may forage on the mud surface and in lower samphire.

Breeding habitat

Breeding is concentrated in dense low shrubs, especially Shrubby Samphire in Gulf St Vincent. Breeding activity can be detected through nests, adults carrying material or food, courtship chasing, begging young and recently fledged birds.

Breeding season: Usually July to October, often following rainfall. Western Australian records include July to September.

Clutch size: Two to four eggs.

Incubation: Not stated in the supplied documents.

Age at maturity: Birds breed in their first year.

Lifespan: Up to 23.5 years.

Generation length: Estimated at 12.3 years.

Nest height: Usually 0.5 to 1 metre above ground and less than 1 metre.

Breeding habitat: Nest habitat

Nests are usually built in dense, divaricate shrubs. The main nesting plant for the Gulf St Vincent subspecies is Tecticornia arbuscula, although nests have also been recorded in Heathy Bluebush, Maireana oppositifolia, where the shrub structure was similar to Shrubby Samphire.

In 2024, eight active nests were found at Torrens Island, Port Gawler, Middle Beach and Baker Creek. Five nests were in Tecticornia arbuscula and three were in Maireana oppositifolia.

  • Retain shrubs one to three metres tall, particularly dense shrubs near tidal channels or saline lakes.
  • Inspect shrubs before clearing during July to October and after rainfall.
  • Search for nests from the edge of dense vegetation where possible, because samphire is brittle and can be damaged by access.
  • Record active nests, eggs, hatchlings, nestlings, adults carrying material and adults carrying food.

Sheltering habitat

Shelter is provided by dense low shrubs, especially samphire and bluebush, with adjacent dune shrubland also used by fledged young. The species does not use tree hollows, burrows or dens according to the supplied documents.

Adults use dense Tecticornia, Sarcocornia, saltbush and bluebush for cover, perching and nesting. Shrubby Samphire stands one to three metres tall provide the best documented structure for the Gulf St Vincent subspecies.

Fledged young have been recorded sheltering for extended periods in dune vegetation and other drier shrubland adjacent to saltmarsh. These areas should not be excluded from site protection simply because they are not samphire.

Shelter height: The main nesting and cover shrubs are commonly 1 to 3 metres tall.

Young bird refuge: Dune vegetation and adjacent shrubland may shelter fledged and dependent young.

  • Protect dense shrub cover around nests and along drainage lines and tidal channels.
  • Retain connected patches of saltmarsh and adjoining dune or shellgrit shrubland.
  • Inspect low shrubs for concealed nests before vegetation removal.
  • Avoid driving or stockpiling materials through samphire, bluebush or adjacent dune shrubland used by young birds.

Sheltering habitat: Nest refuge

The nest is a concealed dome with a side entrance, made from bark, dry seagrass, twigs, grass and spider material. It is placed in the middle or outer structure of a shrub, generally 0.5 to 1 metre above the ground.

  • Do not disturb a shrub containing a dome-shaped nest until the nest status and required protection measures have been confirmed.
  • Keep spotter catcher access outside dense samphire wherever practicable.
  • Where disturbance cannot be avoided, obtain project-specific advice on relocation, exclusion zones and timing from the relevant wildlife authority.

Threats: Clearing and development

The main project risk is loss or degradation of low shrub habitat, particularly dense samphire and bluebush used for nesting and foraging. Coastal hydrology and vegetation condition can change quickly, so habitat assessments should include both the proposed clearing footprint and nearby connected shrubland.

Mining, construction and other development can remove or fragment chenopod shrubland, saltmarsh, dune shrubland and low heath. Clearing of apparently small shrub patches can affect breeding sites, foraging areas and the short-distance movements reported for this species.

The species has a small reported home range, with most recaptures within 100 metres and a reported home range of less than 25 hectares. This makes local habitat loss particularly relevant where suitable shrubs are isolated or already limited.

  • Survey all dense samphire, saltbush, bluebush and low heath within and beside the disturbance footprint.
  • Map habitat within 20 metres of tidal channels, saline lakes, drainage lines and saltmarsh edges.
  • Keep temporary access tracks, laydown areas and spoil outside suitable shrubland.
  • Treat adjacent dune and shellgrit shrubland as potential refuge and post-breeding habitat.

Threats: Grazing, rabbits and fire

Overgrazing by stock and rabbits is identified as the biggest threat in the South Australian fact sheet. Grazing and browsing can reduce shrub density and remove the structure needed for cover and nesting.

Changed fire regimes can damage or remove shrubland habitat. The supplied documents do not provide a species-specific fire interval.

  • Exclude stock and rabbits from retained habitat where practicable.
  • Avoid unnecessary slashing, burning and fuel reduction in known habitat.
  • Record recent fire, grazing pressure, browsing and shrub regeneration during habitat assessment.

Threats: Hydrology, coastal change and vegetation dieback

Sea level rise, altered tidal flows, mangrove expansion, drainage changes and other hydrological changes can alter saltmarsh composition and reduce Shrubby Samphire habitat. Tecticornia arbuscula dieback has been recorded across parts of Gulf St Vincent, with reported local estimates ranging from less than 20 percent to 90 percent in surveyed areas.

The 2024 Gulf St Vincent survey recorded no obvious site-wide decline since earlier surveys but recommended continued monitoring because coastal habitat can change rapidly. Tecticornia dieback may reduce nesting, foraging, perching and sheltering habitat.

Reported Tecticornia dieback: The 2024 survey recorded site estimates from about 10 percent to 90 percent.

  • Assess tidal channels, culverts, embankments, drains and other works that may change inundation or drainage.
  • Retain room for saltmarsh to migrate inland where planning allows.
  • Avoid damaging live samphire during access and construction.
  • Record the extent and severity of Tecticornia dieback before works and during rehabilitation monitoring.

Threats: Other pressures

The supplied conservation material identifies weeds, off-road vehicle use, nutrient enrichment, pest incursions and possible feral predator control as management issues. It does not provide species-specific evidence for disease, road mortality or predation rates.

Pest insect control may reduce prey availability in important marshes. The 2017 assessment recommends reducing other stresses on saltmarsh communities and considering predator management where supported by further research.

  • Prevent weed spread through retained saltmarsh and dune shrubland.
  • Control off-road vehicle access through shrub habitat.
  • Avoid unnecessary insecticide use near known foraging and breeding habitat.
  • Record feral predators and other pest activity, but do not assume a predator management response without site-specific advice.
  • Treat disease, road mortality and predation as information gaps unless project surveys identify a specific issue.

Survey methodology: 1. Habitat assessment and desktop review

Survey effort must target quiet, inconspicuous thornbills in suitable low shrub habitat. Confirm which subspecies may occur, because habitat and state status differ across the range.

Map chenopod shrublands, samphire saltmarsh, saltbush, bluebush, heath on sand plains and mangrove-fringed shrublands before selecting survey locations.

Give particular attention to dense shrubs near salt lakes, salt flats, tidal channels and saline lakes. In Gulf St Vincent, the Samphire Thornbill commonly uses Shrubby Samphire Tecticornia arbuscula and other dense shrubs in coastal saltmarsh.

Review existing records, state databases and local survey reports before concluding that the species is absent. The federal guideline states that an unsupported absence claim may lead to the precautionary principle being applied.

Record habitat condition, shrub height and density, nearby water features, grazing, rabbits, fire history, weeds, dieback and proposed disturbance areas.

Key habitat: Chenopod shrublands, samphire, saltbush, bluebush, heath and mangrove-fringed shrublands.

Preferred Samphire Thornbill habitat: Dense Tecticornia arbuscula shrubland, often within 20 metres of a tidal channel or saline lake.

Survey methodology: 2. Early-morning area searches and transects

Survey suitable habitat on foot by area searches or transects, beginning early in the morning when calling and foraging activity are most likely to be detected.

Listen for calls and watch for birds moving through shrubs, birds flushed from vegetation, feeding activity, pairs, small groups and nests.

Use the survey effort guide for areas less than 50 hectares: 10 hours over 5 days for area searches or transect surveys.

Conduct the main survey during the breeding season where practicable. For the western subspecies, breeding has been recorded from July to September in Western Australia. In South Australia, breeding is reported from July to October, usually after rainfall.

Avoid surveys during strong winds or significant rain where these conditions are likely to reduce detection. In coastal saltmarsh, consider tidal access and avoid damaging brittle samphire while walking.

Recommended effort: 10 hours over 5 days for area searches or transect surveys in areas less than 50 hectares.

Breeding period: Usually July to October in South Australia; July to September recorded in Western Australia.

Detection: Quiet and inconspicuous; detection is most reliable from calls and sightings in suitable habitat.

Survey methodology: 3. Call playback surveys

Use broadcast surveys as a supplementary method where suitable habitat is present and playback will not add unacceptable disturbance.

Use playback during the breeding season, particularly where visual and passive acoustic searches have not established presence or absence.

For areas less than 50 hectares, apply the guideline effort of 6 hours over 3 days.

Allow the observer to listen for call responses and inspect nearby shrubs for birds after each playback sequence. Do not treat a non-response as proof of absence.

Do not use playback around an active nest unless the survey objective requires it and the disturbance has been assessed and authorised.

Recommended effort: 6 hours over 3 days for broadcast surveys in areas less than 50 hectares.

Likely response: The species is probably attracted to playback calls, but it remains shy and inconspicuous.

Survey methodology: 4. Nest and breeding evidence searches

Search dense shrubs for dome-shaped nests with a side entrance. In the Samphire Thornbill, nests are generally 0.5 to 1 metre above ground and are usually placed in Tecticornia arbuscula or another dense shrub of similar structure.

Record eggs, nestlings, fledged young, adults carrying nesting material or food, territorial behaviour and repeated activity at a shrub.

Maintain a safe observation distance and do not touch or open nests unless this is specifically authorised under the relevant wildlife legislation and permit.

In Gulf St Vincent surveys, active nests were found in Tecticornia arbuscula and, at Port Gawler, in dense Maireana oppositifolia. Treat both shrub types as potential nesting habitat where they provide suitable structure.

Nest height: Usually 0.5 to 1 metre above ground for the Samphire Thornbill.

Clutch: Two to four eggs reported for the western subspecies.

Nest form: Dome-shaped, made from bark, grass or seagrass and other soft material, with a side entrance.

Survey methodology: Minimum effort and reporting

Use an ecologist with experience identifying thornbills and their calls to lead or verify the survey.

Record survey dates, start and finish times, weather, wind, rainfall, tidal conditions where relevant, observers, methods, effort, tracks, habitat searched and all detections.

Map every detection, nest, group, fledgling record and area of suitable habitat with coordinates.

Report records, including a nil result, to the relevant state wildlife database and provide the information to the project approval authority where required.

Treat the federal effort guide as guidance rather than a substitute for a site-specific survey design. Document any departure and explain why the alternative method is appropriate.

Do not claim absence solely because no birds were seen during a single visit.

  • Submit verified records to the relevant state wildlife database.
  • Include the taxon name, subspecies where known, coordinates, date, number of birds, behaviour, breeding evidence, habitat and survey effort.
  • Retain photographs, call recordings, GPS tracks and field sheets with the project environmental records.

Before habitat disturbance: Avoid and minimise habitat loss

Plan the project around the species' habitat, breeding period and low detectability. Avoid clearing suitable shrubland wherever practicable, particularly dense samphire and chenopod shrubland near saline water.

Retain dense chenopod shrubland, samphire, saltbush, bluebush and heath patches, especially shrubs that provide nesting cover and perches.

Retain coastal samphire saltmarsh, tidal channels, saline lake margins and the connection between shrub patches and nearby feeding areas.

Avoid placing access tracks, compounds, stockpiles, drainage works and laydown areas through suitable shrubland.

Do not assume that low or sparse saltmarsh is of no value. The Samphire Thornbill may forage in lower samphire, adjacent dune shrubland and other nearby vegetation.

Set site-specific no-go areas around retained habitat and active nests after the survey. The supplied documents do not prescribe a universal buffer distance, so the ecologist must justify the buffer for the machinery, activity, nest stage and habitat.

Home range information: The Samphire Thornbill has been reported to have a home range of less than 25 hectares, with most recaptures within 100 metres and the furthest resighting at 650 metres.

Important nesting structure: Shrubs about 1 to 3 metres tall, particularly Tecticornia arbuscula and dense shrubs of similar form.

Before habitat disturbance: Approvals and work planning

Check whether the affected taxon is listed under the EPBC Act and whether the action is likely to significantly impact it or its habitat before works begin.

Check state threatened species legislation, permits, licences and local approval conditions for the state and subspecies involved.

Prepare a fauna management plan that identifies retained habitat, survey results, exclusion areas, fauna handling arrangements, stop-work triggers, incident contacts and reporting requirements.

Stage clearing so that retained shrubland remains connected and fauna can move to nearby retained habitat without crossing active work areas.

Schedule clearing outside the main breeding period where practicable. If works must occur from July to October in South Australia, or from July to September in Western Australia, increase nest searches and ecological supervision.

Before habitat disturbance: Pre-clearance controls

Complete a pre-clearance inspection immediately before works, using an ecologist who can identify the species by sight and call.

Mark all suitable shrubland, active nests, retained vegetation, access routes and no-go areas on plans and in the field.

Use exclusion fencing where it can protect retained samphire or chenopod shrubland from machinery, vehicles, workers and stored materials.

Brief the spotter catcher, machine operators, supervisors and subcontractors before each clearing stage.

Check for active nests and dependent young on the day of clearing because breeding evidence can change during the project.

During habitat disturbance: Daily controls and machinery coordination

Keep disturbance within the approved footprint and maintain continuous communication between the fauna spotter catcher and machinery operators. Stop work when an animal, nest or unexpected suitable habitat is found.

Inspect exclusion fencing, signs and no-go markers each morning before machinery starts.

Use a fauna spotter catcher during clearing of suitable habitat and whenever machinery approaches retained shrubs, samphire or other mapped habitat.

Keep the spotter catcher in direct communication with the machine operator and supervisor. The operator must stop immediately when directed.

Clear in short, supervised stages from the disturbed edge towards retained habitat, leaving a safe route to the retained area where this is consistent with the approved fauna plan.

Keep vehicles, workers, lighting, dust, noise and stored materials out of retained saltmarsh and shrubland.

  • Stop machinery when the spotter catcher calls stop, raises the agreed stop signal or reports a bird, nest or dependent young in the work area.
  • Do not restart until the spotter catcher and environmental officer agree that the animal has moved or has been safely managed.
  • Maintain a daily record of cleared area, weather, personnel, sightings, nests, incidents, relocations and periods when work stopped.

During habitat disturbance: Handling and relocation

Do not chase, net or handle a Slender-billed Thornbill unless the person is authorised under the applicable wildlife legislation and project approval.

Allow an alert or mobile bird to move into nearby retained habitat where this can occur safely. Do not force it into open ground, traffic areas or active machinery zones.

If capture is unavoidable, use the least stressful lawful method and place the bird in nearby suitable retained habitat identified in the fauna management plan.

Use a release location with dense shrubs, samphire or chenopod cover and access to nearby foraging habitat. Avoid releasing a bird into a bare or heavily disturbed area.

Do not band or mark birds as part of project handling unless the work is undertaken by an appropriately authorised bander. The ABBBS list gives band size 01 for Acanthiza iredalei.

ABBBS recommended band size: 01, with AY metal designation listed for Acanthiza iredalei.

  • Keep handling time as short as possible and keep the bird shaded and quiet.
  • Record the capture location, release location, time held, condition, method, person responsible and any identification details.
  • Take an injured bird to a veterinarian or authorised wildlife carer as soon as practicable and record the transfer.

During habitat disturbance: Nests, habitat features and stop-work triggers

Stop work if an active nest, nestlings, fledglings, a bird repeatedly defending a shrub, or a group of dependent young is found within or immediately beside the work area.

Stop work if clearing would damage dense Tecticornia arbuscula, Maireana oppositifolia or another shrub being used for nesting, shelter or repeated foraging.

Do not remove, move or inspect a nest unless authorised by the relevant wildlife authority and specified in the fauna management plan.

Treat samphire shrubs, low chenopod shrubs, logs, rocks, burrows and wetland margins as fauna habitat even though this species is not dependent on hollow-bearing trees.

Do not enter or drive through brittle samphire saltmarsh unless the route has been assessed and approved. Access damage can reduce nesting and foraging habitat.

  • Stop and contact the environmental officer when the species is found in the clearing footprint.
  • Stop and obtain ecological advice when habitat differs materially from the pre-clearance map.
  • Stop after injury, mortality, nest damage, unauthorised handling or damage to a retained exclusion area, then complete an incident report.

After habitat disturbance: Post-clearance checks

Completion of clearing does not end the fauna controls. Check the disturbed edge, confirm that retained habitat remains functional and document the outcome against approval conditions.

Inspect the cleared footprint and its edge for injured birds, trapped fauna, damaged nests, isolated shrub patches and breaches of exclusion fencing.

Confirm that no machinery, spoil, sediment, weeds or access tracks have entered retained samphire, chenopod shrubland or wetland margins.

Remove temporary fauna hazards, including open trenches, unsecured pipes, netting and uncovered containers, or make them fauna-safe.

Check that birds relocated during works remain in suitable nearby habitat and that any injured animals have been transferred to a veterinarian or authorised wildlife carer.

After habitat disturbance: Monitoring and reporting

Monitor retained habitat and the clearing edge during the remaining works and through the period required by the approval or fauna management plan.

Repeat early-morning searches where clearing removed or fragmented suitable habitat, particularly during July to October in South Australia and July to September in Western Australia.

For Samphire Thornbill sites, monitor shrub condition, Tecticornia arbuscula dieback, nest use, fledged young, group size and use of adjacent dune or shrub habitat.

Use the same search areas, timing and recording method where monitoring is intended to show change over time.

Report deaths, injuries, nest damage, unexpected records, unauthorised clearing and any failure of mitigation to the environmental officer and the relevant approval authority.

  • Submit confirmed species records and significant incident records to the relevant state wildlife database.
  • Provide maps, photographs, effort data, handling records, relocation outcomes and corrective actions in the project completion report.
  • Review the fauna management plan before the next clearing stage when monitoring identifies new habitat use or declining habitat condition.

After habitat disturbance: Offsets and residual impacts

Assess residual impacts under the EPBC Act and relevant state approval frameworks after avoidance, minimisation and rehabilitation have been applied.

Do not use an offset as a substitute for retaining occupied shrubland, active nests, samphire saltmarsh or connected habitat within the project area.

Where an approval requires an offset or conservation contribution, ensure it protects or restores habitat suitable for the affected subspecies and is recorded in the project approvals register.

Rehabilitation actions: Restore suitable shrub habitat

Rehabilitation should recreate dense, low shrub habitat and maintain access to nearby foraging areas. It should be designed for the subspecies and local hydrology, not as generic revegetation.

Where the affected taxon is the western subspecies, restore local chenopod shrubland using locally appropriate saltbush, bluebush and samphire species identified from the pre-clearing survey.

In Gulf St Vincent habitat, prioritise Shrubby Samphire Tecticornia arbuscula where local conditions support it, together with suitable Maireana and other dense shrubs used by the local subspecies.

Aim for a mix of dense shrubs about 1 to 3 metres tall, with lower samphire and nearby shrubland for feeding, shelter and movement.

Restore habitat beside tidal channels, saline lakes and saltmarsh margins where this matches the local hydrology and the original habitat structure.

Do not plant into the wrong tidal elevation or alter drainage without ecological and coastal engineering assessment, because inundation and saltmarsh processes determine which plants can persist.

Preferred nesting shrub height: About 1 to 3 metres for the Samphire Thornbill.

Typical nest height: About 0.5 to 1 metre above ground.

Rehabilitation actions: Protect habitat while it establishes

Fence or otherwise exclude stock, rabbits, vehicles and unauthorised access from revegetation areas until shrubs are established.

Control weeds, pest animals and off-road vehicle damage that reduce shrub cover or change saltmarsh condition.

Manage fire so that large areas of suitable shrubland are not burnt at the same time. Use a site-specific fire plan that considers shrub recovery, nesting season and the need for continuous cover.

Where Tecticornia arbuscula has died back, assess the cause before replanting and monitor whether natural regeneration, alternative shrubs or changed hydrology is affecting establishment.

Retain existing logs, rocks and other ground cover where they occur, but prioritise live dense shrub structure because this is the main nesting and foraging feature documented for the species.

Rehabilitation actions: Success measures and monitoring

Monitor survival, height, density and cover of planted and naturally regenerating samphire and chenopod shrubs.

Record weed cover, rabbit activity, grazing, fire, dieback, tidal inundation, erosion and encroachment by mangroves or other vegetation.

Search restored habitat during early morning in the breeding period using the same area-search and call-detection approach used before disturbance.

Treat successful rehabilitation as more than plant survival: look for Slender-billed Thornbills using the site, repeated detections, pairs, nests, fledged young and movement between restored and retained habitat.

Set measurable completion criteria in the rehabilitation plan, including the required shrub cover and condition, absence of uncontrolled threats, functioning drainage and tidal connections where applicable, and confirmed monitoring visits.

  • Compare rehabilitation results with the pre-clearing habitat map and baseline survey.
  • Investigate and correct failed plantings, severe dieback, weed invasion, erosion or loss of shrub connectivity.
  • Report monitoring results and corrective actions to the approval authority and relevant state wildlife database where required.

Sources