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Australian Masked Owl (Tyto novaehollandiae)

The Australian Masked Owl is a large, nocturnal forest owl found across much of Australia, including Tasmania and the Tiwi Islands. On development sites, it is most relevant where clearing affects old hollow-bearing trees, open forest edges, woodland, grassland or nearby agricultural land used for hunting.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Queensland, Nature Conservation Act 1992: Vulnerable.

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: Endangered.

Tasmania, Threatened Species Protection Act 1995: Endangered.

Northern Territory, Territory Parks and Wildlife Conservation Act 1976: Endangered.

Breeding season

Timing varies between northern Australia, the Tiwi Islands and Tasmania. The months below combine the documented northern pattern with the better documented Tasmanian breeding period; local records should take precedence.

The northern and Tasmanian periods overlap only partly. Confirm local breeding activity before clearing, because the documents record exceptions to the usual seasonal pattern.

  • Breeding, northern Australia: Northern breeding is poorly known but is probably from March to October. Playback is most effective in the lead-up to breeding.
  • Breeding, Tasmania: Most Tasmanian females lay from mid-October to early November. A May nest containing a small chick has also been recorded, so breeding can occur outside the main period.
  • Young in nest or dependent: Northern young may be present during the March to October breeding period. Fledging takes 10 to 12 weeks and young remain dependent for 1 to 3 months after fledging.
  • Movement and dispersal: The species is generally resident or sedentary. Territorial adults usually occur singly or in pairs; juvenile dispersal timing is not described in the supplied documents.
  • Highest clearing risk: Clearing can harm the species whenever occupied hollows, roosts or foraging habitat are removed. Risk is highest during the regional breeding and dependent-young periods, especially March to October in northern Australia and mid-October to early November in Tasmania.

Identification

The Australian Masked Owl is a large, powerful owl with a prominent facial disc and fully feathered legs. It is nocturnal, cryptic and often detected by its call rather than by direct observation.

The facial disc is white to buff, or buff to chestnut in the Tasmanian form, with a dark rim. The upperparts are mottled or streaked with buff, white, chestnut or dark brown, and the underparts are pale with dark spots or chevrons. The legs are completely feathered and the feet are large, with long talons.

Tasmanian form: Up to 1260 g, with a wingspan up to 128 cm.

Northern and Tiwi forms: More than 30 cm long and about 400 g for the Tiwi Islands form; northern mainland birds are smaller than the south-eastern and south-western forms.

Identification: Sex and similar owls

Females are substantially larger and heavier than males and are generally darker. In northern Australia, paler birds can be confused with the Eastern Barn Owl, Tyto javanica, or the Grass Owl, Tyto capensis. The Masked Owl has a more rounded facial disc than the Eastern Barn Owl, thicker completely feathered legs, larger eyes, more robust feet and bolder upperpart markings.

  • Do not rely on plumage colour alone, because the species has light, intermediate and dark plumage forms, with a white male variant reported in northern Australia.

Identification: Field signs

The species is usually located by its call during nocturnal surveys. It can be quiet outside the period before breeding and is difficult to detect by daytime searches. Presence may also be indicated by alarm calls from smaller birds.

  • Look for large tree hollows used as nests or day roosts, especially in old eucalypts and large rainforest trees.
  • Use nocturnal call playback in suitable habitat, particularly before the breeding season. Broadcast surveys are preferred to area searches or transects because the owl is nocturnal and cryptic.
  • Treat any response to playback as a detection only, and manage follow-up work to avoid repeated disturbance near a suspected nest or roost.

Distribution: National range

The species complex occurs across much of mainland Australia and Tasmania, with separate listed subspecies or populations in northern Australia, the Tiwi Islands and Tasmania. The supplied documents describe broad geographic regions rather than formal Australian bioregion boundaries.

The nominate south-eastern and southern form occurs in south-east Queensland, eastern New South Wales, Victoria, southern South Australia and southern Western Australia. The northern mainland form occurs from the Kimberley across the Northern Territory to Cape York Peninsula and far-north Queensland. The Tiwi Islands form is restricted to Melville Island and Bathurst Island. The Tasmanian form is endemic to Tasmania and several near-shore islands, but is absent from King Island and the Furneaux Group.

  • Relevant broad habitat regions include the northern tropical savannas, Kimberley, Top End, Cape York, south-eastern forests and woodlands, southern agricultural and forest mosaics, and Tasmanian forests and woodlands.
  • The species has been recorded in the NT in the western Top End, Cobourg Peninsula, Groote Eylandt, Kakadu National Park, Garig Gunak Barlu National Park, Judbarra/Gregory National Park, Keep River National Park and Nitmiluk National Park.

Distribution: Strongholds and subpopulations

The Tiwi Islands population functions probably as one population across Bathurst and Melville islands, with some dispersal across the narrow Apsley Strait. It is especially common in higher-rainfall areas in north-west Melville Island. The Tasmanian form has its highest densities in eastern and northern Tasmania and its lowest recorded densities above 600 m and in western Tasmania, although fewer western records may partly reflect lower survey effort.

  • The northern mainland form is reported from tall open eucalypt forests and associated monsoon rainforest in the western Top End, Cobourg Peninsula and Groote Eylandt.
  • Lord Howe Island contains an introduced population of the Tasmanian form, but the Tasmanian conservation assessment excludes that population.

Distribution: Population size and trend

Population estimates are not available for the whole species because the documents describe separate forms and populations. Available estimates indicate low numbers for the Tasmanian population and about 1000 breeding individuals for the Tiwi Islands form.

Tasmanian population: Estimated at 520 to 1330 breeding individuals.

Tasmanian extent of occurrence: About 50,000 km².

Tasmanian area of occupancy: About 7300 km².

Tiwi Islands extent of occurrence: About 8000 km².

Tiwi Islands area of occupancy: About 5000 km², with low reliability.

Tiwi Islands population: Estimated at 1000 breeding individuals in one contiguous breeding population.

Trend: The Tasmanian population was suspected to be declining because of habitat loss, but quantitative long-term monitoring was lacking. The Tiwi Islands population was also suspected to be declining, although no recent decline in extent of occurrence was documented.

Habitat: Overall habitat

Masked Owls use a combination of cover for roosting and nesting, and open or semi-open areas for hunting. The most important structural feature for breeding is the presence of large hollow-bearing trees.

The species occurs in a diverse range of forests and woodlands, including agricultural and forest mosaics. It favours forests with relatively open understoreys, especially where they adjoin cleared land, paddocks, grassland or other open vegetation.

  • In northern Australia, look for tall open eucalypt forest and woodland, monsoon rainforest, open woodland, grassland and treeless shrubland.
  • In Tasmania, suitable habitat includes forest, woodland, agricultural land and forest mosaics, particularly at lower elevations and where forest edges adjoin open ground.

Habitat: Vegetation and structure

Northern birds are associated with Darwin Woollybutt, Eucalyptus miniata, Darwin Stringybark, Eucalyptus tetrodonta, and Melville Island Bloodwood, Eucalyptus nesophila. Tiwi birds may roost in monsoon rainforest and forage in grassland or shrubland containing Grevillea pteridifolia, Melaleuca, Acacia and Banksia dentata.

  • Retain large living and dead trees with hollows, including isolated paddock trees and trees along forest edges.
  • Retain connected or nearby cover between hollow-bearing trees and open foraging areas.
  • Treat plantations, mangroves and dense vegetation as potential roosting habitat only where records support their use. The Tiwi form may roost in mangroves and plantations but is unlikely to nest there because suitable hollows are scarce.

Habitat: Elevation and climate

The Tasmanian form has been recorded across Tasmania, but recorded density is lowest above 600 m. The Tiwi form is restricted to the tropical Tiwi Islands, and the northern mainland form occupies tropical and subtropical northern Australia.

Tasmanian elevation pattern: Highest reported densities are in eastern and northern Tasmania; lowest reported densities occur above 600 m and in western Tasmania.

Foraging habitat: Diet

Masked Owls are opportunistic nocturnal predators. They commonly hunt from perches and may also hunt on the wing or take prey from the ground and vegetation.

The diet varies between sites and changes with prey availability and prey size. Tasmanian birds take introduced rodents and rabbits on agricultural land, and arboreal marsupials, terrestrial mammals and native birds in less disturbed habitat. The Tiwi form is presumed to eat mainly mammals, with birds and insects also included.

  • Potential prey includes rodents, rabbits, possums, other small to medium-sized mammals, arboreal mammals, birds and insects.
  • Do not assume that retaining forest alone preserves feeding habitat, because open ground and woodland edges are used for hunting.

Foraging habitat: Foraging areas and method

The species generally forages in open woodland, grassland, paddocks, cleared land, treeless shrubland and forest edges near roosting or nesting cover. It hunts from perches, occasionally on the wing, and takes terrestrial, climbing and arboreal prey.

Home range: The Tiwi Islands home range is unknown. A mainland estimate is 5 to 10 km², while recorded individual or pair ranges elsewhere were about 1.8 km² in Tasmania, 10.2 to 11.8 km² in New South Wales and 11.3 to 13.1 km² in Victoria.

  • Retain open understorey and adjoining clearings where they are connected to forest containing roost or nest hollows.
  • Avoid broad removal of edge trees, isolated perches and sheltering vegetation around known territories.
  • Assess prey habitat as part of the site, including native mammal habitat and areas supporting rodents or rabbits, rather than treating the nest tree as the only relevant feature.

Breeding habitat: Breeding biology

Breeding depends on large hollows in living or dead trees, usually in eucalypts or large rainforest trees. Pairs are territorial and may maintain permanent home ranges.

Breeding timing differs between regions. Tasmanian breeding is strongly seasonal, while northern breeding is less well known and is probably concentrated from March to October. The species usually nests in a large hollow, but may use a vertical spout or limb.

Tasmanian laying period: Most females lay from mid-October to early November.

Northern breeding season: Poorly known, but probably March to October for the northern mainland and Tiwi forms.

Clutch size: One to four eggs, usually two or three.

Incubation: Generally 33 to 35 days, possibly up to 42 days.

Fledging: 10 to 12 weeks.

Post-fledging dependence: Young remain dependent for 1 to 3 months after fledging.

Sexual maturity: About 1 year in the Tasmanian form; age of first breeding is not reported.

Generation length: Estimated at 5 years for the Tasmanian and Tiwi forms.

Lifespan: Not reported in the supplied documents.

  • Manage suspected nest trees and nearby access, lighting, noise and clearing as breeding habitat until nocturnal and hollow inspections establish otherwise.
  • Do not remove dead hollow-bearing trees solely because they are dead if they are stable and can be retained safely.

Breeding habitat: Nest-site features

Nests are usually in large hollows in living or dead trees. In northern Australia, large rainforest trees may form the breeding hollows. In Tasmania, most nest trees are estimated to be more than 150 years old, and nest-tree loss is not being matched by recruitment of younger trees.

Tasmanian nest-tree age: Most nest trees are estimated to be more than 150 years old.

  • Map and retain all large hollow-bearing trees within and adjacent to the proposed clearing area.
  • Retain a buffer of connected forest and foraging habitat around known or suspected nest trees, with the distance set by the site assessment, access needs and relevant approval conditions.
  • Schedule intrusive work outside the relevant regional breeding period where practicable, and use qualified fauna personnel if work must occur near a suspected active nest.

Sheltering habitat: Roosts and refuges

The species roosts during the day and may use tree hollows, dense foliage, monsoon rainforest, mangroves or plantations. Roost and nest locations can be difficult to find because the owl is nocturnal and cryptic.

Tasmanian birds roost during the day in forest and woodland habitat. The Tiwi form often roosts in monsoon rainforest and may also roost in mangroves or Mangium plantations. Northern mainland birds typically roost in tree hollows but may also roost among dense foliage.

  • Inspect large hollow-bearing trees, dense foliage, monsoon rainforest patches and quiet forest edges when assessing potential day roosts.
  • Retain roost trees and the surrounding cover, especially where the same area is close to open foraging habitat.
  • Do not assume that a plantation or mangrove stand provides nesting habitat merely because it may provide a day roost; suitable hollows may be absent.

Sheltering habitat: Site protection

The documents do not specify a universal roost-buffer distance for the Australian Masked Owl. Protection should therefore be based on the confirmed or suspected roost, the surrounding hollow-bearing trees, the access route and the nature and duration of the proposed disturbance.

  • Use nocturnal call playback and targeted inspection to identify likely territories, but avoid repeated playback near an active nest or roost.
  • Retain safe standing dead trees where they contain hollows and can be managed without unacceptable risk to workers or the public.

Threats: Clearing and fragmentation

The main project risks are removal of hollow-bearing trees, loss of connected hunting habitat, disturbance near breeding sites, and mortality associated with roads, power infrastructure and toxicants.

Agriculture, forestry, plantations, residential development and infrastructure can remove large hollow-bearing trees and reduce open forest and woodland used for hunting. Fragmentation can separate nest trees from foraging areas and reduce the availability of permanent territories.

  • Survey before clearing for large living and dead hollow-bearing trees, suspected nest hollows, day roosts and adjoining open foraging habitat.
  • Retain mature paddock trees, forest edges and tree groups that connect hollows with open land.
  • Avoid removing isolated old trees during plantation establishment, irrigation works, road construction or utility installation.

Threats: Fire, vegetation change and prey loss

Altered fire regimes can reduce large trees and hollows in northern Australia and change the structure of vegetation used for hunting. Invasive grasses, weeds and plantation development may reduce native mammal prey. Declines in small and medium-sized mammals are an indirect threat to northern birds.

  • Avoid intense, frequent or extensive fire that removes old hollow-bearing trees and dense roosting cover.
  • Manage fire and invasive grasses in a way that retains large trees, hollows, open foraging areas and native prey habitat.
  • Assess cumulative effects where clearing, fire and changed vegetation structure occur in the same territory.

Threats: Mortality and disturbance

The species is at risk of secondary poisoning after eating rodents or other animals exposed to brodifacoum, 1080 or Pindone. Frequent use of forest edges, paddocks and cleared land increases the risk of collisions with vehicles and powerlines. Competition with other hollow-dependent species may increase where hollows are scarce.

  • Use non-toxic pest control methods where practicable near known or potential owl territories, and prevent access to poisoned prey by wildlife.
  • Plan vehicle movements, temporary lighting and overhead infrastructure to reduce risk along forest edges and near known territories.
  • Retain replacement hollow resources only where they are supported by a site-specific conservation plan; nest boxes are a feasibility option identified for territories lacking adequate hollows, not a substitute for retaining old trees.

Threats: Survey and approval risk

Playback surveys are the recommended method for the northern mainland and Tiwi forms, especially in the months before breeding. Area searches and transects are unlikely to detect the species reliably. A confirmed or suspected owl territory should be referred to the relevant approval and fauna management process before clearing proceeds.

  • Use broadcast surveys in suitable habitat with the documented effort guide of 8 hours over 4 days for the northern mainland and Tiwi forms where that guide applies.
  • Have a qualified ecologist assess any response, roost, nest, feather, prey remains or repeated owl activity before disturbance.
  • Treat the absence of a playback response as inconclusive outside the most suitable survey period.

Survey methodology: 1. Call playback surveys

The Masked Owl is nocturnal, cryptic and often quiet. Survey methods must target calls in suitable habitat, particularly before breeding, and must account for the relevant subspecies or population.

Use broadcast surveys in suitable habitat, especially in the period leading up to breeding. Listen for solicited responses because the owl is usually detected by call.

For the northern mainland and Tiwi Islands subspecies, area searches and transect surveys are unlikely to be useful because the owls are nocturnal and cryptic.

For the Tasmanian population, target forest and woodland mosaics with relatively open understoreys adjoining open or cleared land, and inspect habitat containing large hollow-bearing trees.

Guideline effort for northern mainland and Tiwi Islands subspecies: 8 hours over 4 days of broadcast surveys

Best timing stated in the guidelines: Lead-up to the breeding season

Useful detection cues: Nocturnal calls, increased calling before breeding, and occasional alarm calls from smaller birds during the day

Survey methodology: 2. Nocturnal habitat assessment

Conduct a daytime habitat inspection before playback to locate tall open eucalypt forest, woodland edges, monsoon rainforest, open foraging areas and large hollow-bearing trees.

For the Tasmanian population, inspect living and dead trees with large hollows, vertical spouts or suitable limbs because these features may be used for nesting.

For northern populations, give particular attention to tall open eucalypt forest dominated by Darwin Woollybutt, Darwin Stringybark or Melville Island Bloodwood, together with adjoining grassland or other open foraging habitat.

Tasmanian breeding period: Most females lay from mid-October to early November

Northern mainland breeding period in the survey guideline: Poorly known, probably March to October

Typical nest feature: A large tree hollow, usually in a eucalypt or large rainforest tree

Survey methodology: 3. Follow-up and targeted searches

Repeat playback where habitat is suitable but an initial survey does not detect the owl, particularly where large hollows, recent records or potential nest sites are present.

Use targeted nest-site inspections only where they can be completed safely and without disturbing a breeding pair or dependent young.

Do not rely on daytime area searches or ordinary transects as the primary detection method for this owl.

Survey methodology: Minimum effort and reporting

  • Apply the survey guideline effort of 8 hours over 4 days of broadcast surveys for the northern mainland and Tiwi Islands subspecies where that guideline applies.
  • Use the Tasmanian population's breeding season, habitat and known nest-site information to design additional targeted survey effort where the project may affect large hollow-bearing trees or established territories.
  • Record the survey date, start and finish time, weather, survey points, playback sequence, habitat, calls heard, visual observations and any response distance and direction.
  • Treat a suspected response as a record requiring verification by a suitably experienced ecologist, particularly where the call could be confused with another nocturnal bird.
  • Submit verified records, including negative results where requested, to the relevant state or territory wildlife database and provide records required by project approvals.
  • Check current state and territory survey guidance before fieldwork because the available guideline information differs between the northern mainland, Tiwi Islands and Tasmania.

Before habitat disturbance: Avoid and minimise habitat loss

Plan the project around the owl's dependence on large tree hollows, connected roosting and foraging habitat, and quiet nocturnal territories. Confirm the relevant subspecies and all Commonwealth, state or territory requirements before clearing or construction starts.

Retain large living and dead hollow-bearing trees, including trees with hollows, vertical spouts and large limbs that could provide nest sites.

Avoid clearing forest and woodland edges that connect roosting habitat with open or cleared foraging areas.

Retain connected blocks of tall open eucalypt forest, woodland, rainforest roosting habitat and open feeding areas where practicable.

In Tasmania, give priority to old nest trees because most known nest trees are estimated to be more than 150 years old and tree recruitment is limited.

On the Tiwi Islands, apply the plantation forestry prescription of retaining native forest for 100 metres around known roost or nest sites where it forms part of the project's applicable approval or management requirements.

Before habitat disturbance: Confirm approvals and plan the works

Check whether the affected population or subspecies is listed under the EPBC Act and whether the proposed action requires referral, approval or conditions before habitat is disturbed.

Check the relevant state or territory listing, development controls, wildlife permits and fauna handling requirements before works begin.

Prepare a fauna management plan that identifies survey results, retained habitat, hollow-bearing trees, exclusion areas, nocturnal work controls, fauna handling responsibilities and stop-work triggers.

Stage clearing so that retained habitat remains connected and fauna can move to suitable retained habitat before isolated patches are removed.

Schedule noisy or habitat-disturbing activities to avoid known breeding periods where practicable, including mid-October to early November in Tasmania and the probable March to October breeding period used for northern mainland surveys.

Before habitat disturbance: Prepare and mark the site

Complete the required pre-clearance survey using targeted nocturnal call playback and a daytime habitat inspection before machinery enters the work area.

Mark exclusion zones around known or suspected nest trees, roost sites, retained forest and other habitat features identified in the fauna management plan.

Use exclusion fencing or other clearly visible controls where they can prevent machinery entry without blocking owl movement between retained habitat patches.

Brief operators and spotter catchers on the owl's appearance, nocturnal behaviour, call-based detection, hollow dependence and the project's stop-work procedure.

During habitat disturbance: Daily controls and machinery coordination

Clearance must be supervised by an appropriately authorised fauna spotter catcher and controlled through the approved fauna management plan. The owl is nocturnal and may be difficult to detect, so machinery controls and habitat protection are as important as searching for the animal itself.

Inspect exclusion fencing, retained habitat markers and access controls before work starts each day.

Keep machinery outside marked nest-tree, roost-site and retained-habitat exclusion areas unless the authorised environmental representative approves a change.

Use a staged clearing sequence that directs fauna towards retained habitat and avoids leaving isolated hollow-bearing trees exposed to later collapse or accidental removal.

Where nocturnal works are proposed, assess lighting, noise and vehicle movements as potential disturbance to roosting, foraging or breeding owls and apply the approved controls.

Maintain clear communication between the spotter catcher, machine operator, supervisor and environmental officer, using an agreed stop-work signal.

During habitat disturbance: Habitat feature handling

Do not fell or damage a known or suspected nest tree, roost tree or large hollow-bearing tree unless the action is specifically authorised and the fauna management plan provides a safe method.

Inspect trees, limbs and hollows that are approved for removal for owls or dependent young before disturbance, using an appropriately authorised and experienced person.

Retain fallen hollow limbs, large logs and other habitat features where they can provide shelter or maintain habitat structure, unless their removal is required for safety or an approved construction purpose.

Avoid unnecessary disturbance to adjoining forest, woodland, rainforest roosting areas and open foraging habitat while removing approved vegetation.

During habitat disturbance: If an owl is found

Stop the activity that could affect the owl and notify the fauna spotter catcher and environmental officer immediately.

Do not handle, chase, feed or relocate the owl unless the person is authorised under the applicable state or territory requirements and the action is necessary for its welfare or safety.

Keep workers, vehicles and machinery away from the owl and allow it to move naturally to nearby retained habitat where safe to do so.

If capture is necessary, use only the approved method and release the owl into suitable nearby retained habitat agreed by the fauna spotter catcher and environmental officer.

Take an injured owl to an appropriately experienced veterinarian or authorised wildlife carer as soon as practicable, following the relevant wildlife authority requirements.

Treat an owl at a nest, a dependent young bird, an occupied hollow or an injured bird as a stop-work trigger until the authorised fauna specialist and environmental officer approve recommencement.

During habitat disturbance: Records and stop-work triggers

  • Stop work for any confirmed or suspected Masked Owl, occupied or potentially occupied nest hollow, dependent young, injured bird, damaged exclusion control or unexpected loss of retained habitat.
  • Record the location, date, time, activity, habitat feature, bird condition, photographs where appropriate, people involved, handling or treatment and final outcome.
  • Record all incidents involving a collision, poisoning risk, tree or hollow damage, vehicle strike or other mortality.
  • Do not recommence work until the authorised fauna specialist and the responsible environmental officer have assessed the risk and documented the control or approval to proceed.

After habitat disturbance: Post-clearance checks

After clearing, confirm that retained habitat and controls remain intact, check for displaced or injured fauna, and document whether the work complied with approvals and the fauna management plan.

Inspect the cleared edge and retained habitat for injured, trapped or displaced owls, damaged nest trees and accidental removal of hollow-bearing trees.

Check that retained habitat remains connected to other forest, woodland, rainforest roosting areas and open foraging habitat identified during planning.

Remove or repair temporary controls only after the environmental officer confirms that no further construction risk remains and that required habitat protection measures are complete.

After habitat disturbance: Monitoring and reporting

Repeat targeted call playback monitoring where the project affects a known territory, nest site, roost site or substantial area of suitable habitat and where monitoring is required by approval.

Monitor the condition of retained hollow-bearing trees and nearby habitat because tree dieback, clearing and fragmentation can continue to reduce nesting habitat after construction.

Report survey results, incidents, mortalities, fauna handling, habitat loss, rehabilitation progress and any corrective actions to the approval holder and relevant wildlife authority.

Update the relevant state or territory wildlife database with verified records and submit Commonwealth reports where required by an EPBC Act approval or condition.

After habitat disturbance: Offsets and compliance actions

Apply any approved offset, compensatory habitat measure or conservation covenant required for the project.

Where approved controls were not achieved, document the breach, notify the responsible authority where required and implement the agreed corrective action.

Retain evidence of pre-clearance surveys, exclusion-zone inspections, machinery briefings, daily fauna logs and post-clearance checks for audit.

Rehabilitation actions: Restore habitat structure

Rehabilitation should restore the habitat structure used by Masked Owls for roosting, nesting and foraging. Large hollows take many decades to form, so protecting existing hollow-bearing trees is more effective than relying on new plantings alone.

Retain and protect surviving large living and dead hollow-bearing trees throughout rehabilitation areas.

Replant locally appropriate eucalypt forest and woodland species that match the affected site, including Darwin Woollybutt, Darwin Stringybark or Melville Island Bloodwood where those species form the local habitat on the Tiwi Islands.

In Tasmania, restore forest and woodland mosaics with relatively open understoreys adjoining open or cleared foraging areas, while retaining mature trees and dead standing habitat where safe.

Maintain links between roosting habitat, nesting trees and open foraging areas rather than creating isolated planting blocks.

Rehabilitation actions: Replace lost nesting opportunities

Do not remove a hollow-bearing tree solely because a nest box is available; retain the tree wherever safety and approvals allow.

Assess nest boxes only as a supplementary measure in territories that lack adequate hollows, because their feasibility and usefulness require site-specific assessment.

Place any approved nest boxes under advice from a suitably experienced owl ecologist and monitor their use, condition and exposure to competing hollow users.

Rehabilitation actions: Manage threats in restored areas

Control invasive weeds and exotic grasses that can alter vegetation structure, reduce prey availability or reduce hunting efficiency.

Develop fire management with the relevant land manager to maintain suitable forest, woodland and open foraging habitat and to protect large trees and hollows.

Avoid rodenticide, 1080 and pindone practices that could expose owls to secondary poisoning, and require an approved risk assessment for any vertebrate pest control near habitat.

Manage vehicle and powerline collision risks at forest edges, cleared land and paddocks through the project design and operational controls.

Rehabilitation actions: Monitor rehabilitation success

  • Inspect planted areas, retained trees, nest boxes, weed control and fire-management outcomes at the intervals specified in the approval or rehabilitation plan.
  • Use targeted call playback to monitor Masked Owl use where suitable habitat has been restored, applying the northern and Tiwi guideline effort of 8 hours over 4 days where that guideline is relevant.
  • Measure success by survival of retained hollow-bearing trees, establishment of connected forest and woodland habitat, maintenance of open foraging areas, reduced weed and fire risk, and verified owl records or use of retained habitat.
  • Adapt rehabilitation measures if monitoring shows loss of hollows, poor tree establishment, habitat fragmentation, reduced prey habitat or continuing collision and poisoning risks.

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