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Morepork (Ninox novaeseelandiae)

The EPBC Act listed Norfolk Island population of the morepork, Ninox novaeseelandiae undulata, occurs on Norfolk Island and is concentrated in native and weed-managed forest in and around Norfolk Island National Park. It is Endangered, with a very small population, restricted breeding range and limited nesting habitat, so clearing, tree removal, weed control, nest-box disturbance and introduced predators require careful management on development sites.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Breeding season

The Norfolk Island morepork is sedentary and present throughout the year. Breeding and fledging activity is concentrated from late September through the summer period.

Timing is based on the Norfolk Island population. Local nesting observations and current nest-box monitoring should take priority over the typical calendar when planning works.

  • Breeding: Laying occurs from late September to early October, with incubation lasting about 31 days.
  • Young: Nestlings fledge in early December and remain in the natal territory for several months.
  • Movement or dispersal: The population is regarded as sedentary. No regular migration pattern is documented.
  • Highest clearing risk: The highest risk is around active nests from laying in September and October through fledging and the period when dependent young remain in the natal territory. Clearing near known nests or nest boxes should be avoided during this period.

Identification

The listed Norfolk Island population is a small, secretive boobook owl. It is more often detected by its call than seen, particularly at night or around the start of the breeding season.

Adults are compact brown owls with a dark facial disc, pale border and whitish eyebrows. The upperparts are dark brown with pale spots and streaks, while the underparts are pale to light brown with dark streaking and pale, dark-barred feathers. The iris is yellow to brownish yellow, and the talons are brown or blackish.

Length or height: About 29 cm for the species; historical Norfolk Island birds were 30 to 35 cm tall.

Weight: 179 to 216 g for the species.

Identification: Similar species and sex differences

There is no similar owl species on Norfolk Island. The remaining Norfolk Island birds are hybrids involving the New Zealand subspecies and are phenotypically indistinct from that subspecies. The original genetically pure form is extinct. Plumage was similar between the sexes, although females may have had more spotting and were slightly larger than males.

Identification: Calls and field signs

The characteristic call is a repeated, two-note whistle that can sound like "more-pork". A high-pitched, vibrating call may also be heard during the breeding season. Calls can carry for up to 1 km, depending on topography and conditions.

The species is inconspicuous by day and usually remains in dense cover. A day roost may be indicated by whitish excreta and pellets on foliage or on the ground below the roost. Active nest boxes can provide stronger evidence than visual searches, but boxes should only be checked under an approved monitoring procedure.

Distribution

In Australia, the EPBC listed entity is restricted to Norfolk Island, an Australian external territory. It is not recorded as a mainland Australian species in the supplied documents.

The population is endemic to Norfolk Island. Most records are from the Mount Pitt region of Norfolk Island National Park, which covers about 460 ha, although occasional observations have been made elsewhere on the island.

The current breeding range is largely confined to suitable habitat within Norfolk Island National Park. Historically, the genetically pure form probably occurred more widely across Norfolk Island and in small numbers on Phillip Island.

Australian range: Norfolk Island only.

Main stronghold: Mount Pitt region and suitable forest within Norfolk Island National Park.

Formal state or mainland distribution: No Australian state records or mainland range are given in the supplied documents.

Formal bioregion: No formal Australian bioregion is specified in the supplied documents.

Distribution: Population size and trend

The population declined to a single female in the 1980s. A New Zealand male was introduced in 1989, and subsequent hybridisation prevented extinction of the remaining population. The 2020 estimate was approximately 25 mature individuals, with high confidence.

Successful fledging was recorded in 2020 after more than a decade without known successful breeding. The population remains highly inbred and very small.

Area of occupancy: Less than 10 km2 in the 2016 conservation advice.

2020 estimate: Approximately 25 mature individuals.

Earlier threshold: Fewer than 50 mature individuals.

Recent breeding outcome: Chicks survived to fledging in 2020 after no known successful breeding since 2012.

Habitat: Habitat types

The Norfolk Island morepork uses forested habitat with suitable night foraging areas and secure daytime roosts. It is associated with relatively open understorey rather than dense woody weed infestations.

The main habitat is native forest and weed-infested forest with a clear understorey. The species has also been recorded in Eucalyptus plantations and suburban areas, but the current breeding range is largely within suitable habitat in Norfolk Island National Park.

Habitat: Structural features

Important habitat features include mature trees with hollows, open or relatively clear understorey, dense foliage for daytime concealment and forest canopy used for nocturnal hunting. Introduced weeds can create a dense understorey that is unsuitable and can replace native plants used as nesting sites.

Primary habitat: Native forest, including forest in Norfolk Island National Park.

Preferred understorey: Relatively clear and free of dense woody weeds.

Other recorded habitat: Eucalyptus plantations and suburban areas.

Habitat: Elevation and climate

The supplied Norfolk Island sources do not provide an elevation limit or a quantified climate range. The species is described as sedentary on Norfolk Island and uses habitat throughout the year.

Foraging habitat: Diet

The morepork hunts at night, mainly from forest perches and usually in or around the canopy. Breeding birds tend to forage close to the nest.

The diet includes insects such as moths, crickets, katydids, beetles and other invertebrates. Vertebrate prey includes small birds, rats and other small vertebrates. Vertebrates are likely to be taken more often during the breeding season.

Invertebrate prey: Moths, crickets, katydids and beetles.

Vertebrate prey recorded or reported: White Terns, Scarlet Robins, Slender-billed White-eyes, Silvereyes, blackbirds, song thrushes and rats.

Foraging habitat: Foraging method and area

Birds begin hunting around dusk and commonly take prey from exposed perches, either pouncing onto prey on the ground or pursuing prey in the air. Norfolk Island birds usually hunt in the canopy. The territory and home range of the hybrid population are unknown; the last pure-bred female was mainly recorded within an area of less than 200 ha.

Activity period: Nocturnal, with activity beginning around dusk.

Typical hunting level: Usually the canopy, with prey also taken on or near the ground.

Known area used: Less than 200 ha for the last pure-bred female; current hybrid home range is unknown.

Breeding habitat: Breeding biology

Breeding requires a secure nest site, suitable forest around the nest and control of introduced nest competitors. The current population relies predominantly on nest boxes, although tree hollows may still be used.

Pairs traditionally nested in tree hollows but now predominantly use deep nest boxes. Females lay one clutch, and the male supplies food while the female incubates. Young leave the nest in early December and remain in the natal territory for several months.

Breeding season: Laying from late September to early October.

Clutch size: Two eggs.

Incubation: About 31 days, by the female.

Fledging: Early December.

Age at first breeding: Two to three years for the Norfolk Island population.

Longevity: Unknown overall; the last pure-bred female was more than 20 years old when last observed.

Breeding habitat: Breeding habitat features

Breeding habitat includes suitable forest with a relatively clear understorey, mature trees containing hollows and installed nest boxes. Nest boxes can be made unsuitable by European starling nesting material or occupied by crimson rosellas. Nest sites may also require predator protection and monitoring for cats, rats and European honey bees.

  • Retain mature hollow-bearing trees and avoid disturbing known nest trees or nest boxes.
  • Keep clearing, construction noise and night lighting away from known active nest sites where practicable.
  • Before works near suitable forest, obtain current nest-site information from the relevant Norfolk Island conservation authority and use approved survey and exclusion procedures.
  • Do not remove, open or relocate a nest box without authorisation and species-specific supervision.

Sheltering habitat: Day roosts

The species shelters by day in concealed dense foliage and breeds in hollows or deep nest boxes. Roost and nest sites can be identified from droppings, pellets and repeated calling around dusk.

Moreporks spend the day resting on concealed perches behind dense foliage. Roosts may be indicated by whitish excreta and pellets on foliage or on the ground below the site.

Sheltering habitat: Nest sites

Traditional nest sites were tree hollows. The current Norfolk Island population predominantly uses deep nest boxes, with occasional use of tree hollows. The supplied documents do not give a minimum hollow diameter, tree diameter or nest-box dimensions.

Natural shelter and nest sites: Tree hollows and concealed dense foliage.

Artificial nest sites: Deep nest boxes, now used predominantly by the population.

Known site dimensions: No hollow, tree or nest-box dimensions are provided in the supplied documents.

  • Treat deep nest boxes, hollow-bearing trees and cavities in mature trees as potential breeding resources until checked by an appropriately authorised person.
  • Retain dense foliage around likely day roosts where it can be done safely and consistently with approved habitat management.

Threats: Clearing and habitat change

The main development risks are loss of mature trees and forest structure, disturbance of nest sites, weed-driven habitat degradation and introduced species competing for hollows or preying on eggs, nestlings and adults.

Historical clearing for agriculture and felling of large trees removed most suitable nesting sites and caused the major decline of the genetically pure population. Current habitat degradation from wild tobacco, red guava, African olive and lantana can create dense understorey and reduce native nesting plants.

Because the remaining population is small and concentrated in a restricted area, removal of even individual nest trees or nest boxes can affect breeding capacity.

  • Survey native forest, mature hollow-bearing trees, dense day-roost cover and existing nest boxes before clearing.
  • Avoid removing mature trees or changing the understorey around known or potential nest sites unless the work forms part of an approved recovery action.
  • Stage weed removal so that nest sites, roosts and foraging cover are not lost during the breeding season.

Threats: Introduced species and predation

Crimson rosellas compete for nest boxes and can expel moreporks from territories. European starlings fill nest boxes with unsuitable material. Black rats and Polynesian rats may take eggs or nestlings, cats are a suspected predator, and European honey bees may occupy nest sites or injure birds.

  • Inspect active or potential nest boxes for rosellas, starlings and honey bees before works.
  • Prevent construction materials, temporary structures and waste from creating additional shelter or access for cats and rats near known nest sites.
  • Do not use rodent bait near foraging or nesting areas unless the method has been approved for the site and secondary poisoning risk has been assessed.

Threats: Other project pressures

The supplied documents do not identify roads, traffic, disease or hydrology change as established threats for this population. Wildfire and cyclones are identified as stochastic risks because the population is very small. Construction planning should still avoid unnecessary night lighting, loud night work and disturbance around known roosts or nest sites.

Survey methodology: 1. Spotlighting and area searches

This profile applies to the EPBC Act listed Norfolk Island boobook owl, also called the Norfolk Island morepork, Ninox novaeseelandiae undulata. Confirm the taxon before work starts, because the widespread New Zealand subspecies is not the same listed entity. The listed population is sedentary, nocturnal and usually detected by its call rather than by sight.

Search suitable native forest, weed-infested forest with a clear understorey, and relevant Eucalyptus plantation habitat. Give particular attention to the Norfolk Island National Park and areas with nest boxes or known breeding pairs.

Begin searches just before dusk and continue at night with a spotlight. Listen for the first call made when birds leave day roosts, then check foliage and ground beneath likely roosts for whitish excreta and pellets.

Conduct area searches or transect-point surveys over 12 hours on 4 days in areas smaller than 50 ha. Schedule the work before and during the breeding season, when calling is more frequent.

Breeding season: Laying from September to October; fledging from December to January.

Daily activity: Mainly nocturnal, sometimes crepuscular.

Call detectability: A call may be heard from up to 1 km, depending on topography and conditions.

  • Record the search area, transect route, start and finish times, weather, wind, moon or artificial light conditions, observers, spotlight use and all calls or sightings.
  • Treat a call as a detection even when the bird cannot be seen, and record its bearing, estimated location and whether it responded to another bird or observer.

Survey methodology: 2. Broadcast surveys

Use broadcast surveys in suitable habitat when area searches or transects do not detect birds, particularly where density is low. Conduct them early in the breeding season, before egg laying, when responses are most likely.

Use playback from suitable listening stations and remain quiet while listening for solicited responses. Avoid excessive playback and follow the project fauna management plan and any permit conditions.

  • Complete 8 hours of broadcast surveys over 4 days for areas smaller than 50 ha.
  • Record the playback content, duration, station locations, time between broadcasts, weather, observer position and every response or non-response.
  • Do not treat a lack of response as proof that the species is absent, because the owl is secretive and may remain in dense cover.

Survey methodology: 3. Nest-box, hollow and roost checks

Inspect known nest boxes for signs of active use, subject to access approval and any site-specific conservation directions. The population now predominantly uses nest boxes, although tree hollows remain relevant.

Search for roosts by checking concealed foliage and the ground below likely roost sites for pellets and whitish excreta. Do not open or disturb an occupied hollow or nest box unless this is authorised under the fauna management plan.

Nest use: Pairs traditionally used tree hollows and now predominantly use nest boxes.

Clutch and incubation: Usually 2 eggs, incubated by the female for about 31 days.

  • Map every nest box, hollow-bearing tree and confirmed roost that could be affected by the works.
  • Coordinate checks with the Norfolk Island conservator or relevant land manager where breeding pairs are known or birds are banded.
  • Use the same nest-site locations and methods in repeat surveys so that occupancy and breeding success can be compared.

Survey methodology: Minimum effort and reporting

  • Use the species-specific minimum effort of 12 hours over 4 days for area searches or transect surveys, or 8 hours over 4 days for broadcast surveys, for areas smaller than 50 ha.
  • Survey before and during the September to October laying period where practicable, and repeat the work if conditions, access or detectability were unsuitable.
  • Report the taxon as Ninox novaeseelandiae undulata where the EPBC listed Norfolk Island population is involved, rather than recording it only as the generic common name Morepork.
  • Submit records, including positive, negative and incidental records, to the relevant state or territory wildlife database and to the Norfolk Island land manager or conservator where applicable.
  • Retain spatial data, call recordings, photographs, nest-box results, survey effort, weather and observer details with the project environmental records.
  • Refer any proposed action that may significantly affect the EPBC listed population to the Australian Government referral process and obtain all required state, territory and local approvals before disturbance.

Before habitat disturbance: Avoid and minimise

Plan the work around the owl's small, single population and restricted breeding habitat. The main project risk is loss or disturbance of remaining forest, nest hollows, nest boxes and clear-understorey habitat.

  • Retain native forest, suitable Eucalyptus plantation habitat, clear-understorey foraging areas, nest boxes, hollow-bearing trees and known roosts wherever practicable.
  • Keep confirmed nest sites, roosts and regularly used foraging areas within retained habitat, and avoid isolating them from nearby forest.
  • Do not clear vegetation heavily infested with weeds without first checking for occupied nest boxes, hollows and roosts, because the species may still use modified forest and plantation habitat.
  • Control project-related disturbance near known breeding sites and avoid removing large trees that could provide current or future nesting hollows.

Before habitat disturbance: Approvals and work planning

  • Check whether the action may significantly affect Ninox novaeseelandiae undulata and complete an EPBC Act referral assessment before works commence.
  • Obtain any required state, territory, Norfolk Island and local permits, including permissions for handling, trapping, spotlighting, playback, nest-box access or wildlife relocation.
  • Prepare a fauna management plan that identifies survey results, exclusion areas, approved handling personnel, stop-work triggers, nest-box protection, rehabilitation and reporting requirements.
  • Stage clearing so that retained habitat and nest boxes remain available while adjoining works proceed, and schedule noisy or high-disturbance activities outside confirmed breeding activity where practicable.
  • Use September to October as the key period for breeding risk planning, with additional controls through fledging from December to January.

Before habitat disturbance: Pre-clearance preparation

  • Complete the species-specific survey before clearing, using spotlighting, call detection, broadcast surveys and nest-box checks as appropriate to the site.
  • Mark all confirmed records, nest boxes, hollow-bearing trees, roosts, retained forest and no-go areas on plans and on the ground before machinery arrives.
  • Install exclusion fencing around retained habitat and nest sites where it can prevent machinery entry without blocking normal owl movement.
  • Brief machinery operators and the fauna spotter catcher on the owl's call, nocturnal activity, likely roost signs, site controls and the process for stopping work.

During habitat disturbance: Daily controls and machinery coordination

Use an active fauna spotter catcher during vegetation removal and any activity that could affect a nest, roost or hollow-bearing tree. The spotter catcher must have authority to pause work and must record all detections and responses.

  • Inspect exclusion fencing, retained habitat, nest boxes and marked trees before work starts each day.
  • Keep machinery outside marked exclusion areas and use staged, slow clearing where habitat features are close to the work zone.
  • Position the fauna spotter catcher where they can see the clearing face, machinery movements and any falling tree or branch, and stop the operator before a detected animal or occupied feature could be harmed.
  • Do not conduct night clearing unless it is specifically approved and controlled, because the owl is nocturnal and may be away from its roost or nest.

During habitat disturbance: Habitat features and occupied sites

  • Treat hollow-bearing trees, nest boxes and confirmed roost trees as protected features until inspected and cleared by the authorised fauna spotter catcher.
  • Do not fell a tree containing an occupied hollow or active nest box until the fauna management plan identifies an approved method, timing and supervisor for the action.
  • If a nest box must be moved, use an approved wildlife specialist and retain the box, its orientation and suitable nearby habitat wherever practicable.
  • Manage logs, rocks, burrows and wet areas under the broader project fauna plan if they occur, but do not assume they are Morepork habitat features unless a survey or site assessment identifies their relevance.

During habitat disturbance: Animal encounters, stop-work and records

  • Stop work immediately if a Morepork is found in the clearing area, inside a tree or nest box scheduled for removal, injured, trapped, or showing behaviour consistent with an occupied breeding site.
  • Allow the authorised fauna spotter catcher to assess the bird and limit handling to what is necessary for immediate safety, approved relocation or veterinary care.
  • Relocate a healthy bird only under the approved fauna management plan and only to nearby retained habitat that is suitable for the species and outside the active work area.
  • Take an injured bird to an appropriately qualified veterinarian or licensed wildlife carer, and record the transfer and advice received.
  • Resume work only after the fauna spotter catcher and environmental officer confirm that the stop-work trigger has been resolved and any required approval or variation is in place.
  • Record the date, time, location, behaviour, call or sighting, habitat feature, action taken, handler, photographs, fate and any relevant permit or approval number.

After habitat disturbance: Checks and monitoring

Post-clearance checks must confirm that no owl, nest, roost or protected habitat feature was missed. Monitoring should focus on occupancy, breeding and the threats identified for the Norfolk Island population.

  • Inspect the cleared area, retained trees, nest boxes and exclusion boundaries after each clearing stage and again before the next stage begins.
  • Repeat spotlighting, call detection and nest-box checks at retained habitat where works could have changed access, vegetation structure or disturbance levels.
  • Monitor known nest sites for crimson rosellas, European starlings and European honey bees, and maintain monitoring of rats and cats where these controls form part of the project.
  • Track population observations, nest occupancy, breeding success, fledging and use of retained habitat, and compare results with the pre-work baseline.

After habitat disturbance: Controls, reporting and offsets

  • Maintain exclusion fencing, nest-box protection, predator controls and weed controls for the period specified in the fauna management plan, not only during active clearing.
  • Report unexpected deaths, injuries, nest failure, habitat loss, new breeding records and any breach of the approved controls to the environmental officer and relevant regulator or land manager.
  • Submit final survey and monitoring records to the relevant state or territory wildlife database and, for Norfolk Island records, to the relevant Norfolk Island land manager or conservator.
  • Implement any approved offset or other compensatory measure required under the EPBC Act, approval conditions or state and territory law, and document its location, management and monitoring.

Rehabilitation actions: Restore habitat and nesting sites

Rehabilitation should restore the forest structure and nesting opportunities used by the Norfolk Island boobook owl. It should also reduce weeds and introduced species that compete for nest sites or affect breeding habitat.

  • Revegetate suitable disturbed areas with locally appropriate native plants as part of weed control and habitat restoration in and around retained forest.
  • Restore a relatively open understorey where the species requires clear foraging and nesting access, while retaining dense foliage used for concealed day roosts.
  • Install and maintain deep nest boxes where natural hollows are unavailable, using the design, placement and predator protection approved by the land manager or recovery program.
  • Retain or reinstate large native trees and other features that can provide future hollows, and protect them from machinery, fire and competing nest users.

Rehabilitation actions: Weed, pest and fire management

  • Control wild tobacco, red guava, African olive, lantana and other weeds that create a dense understorey or displace native nesting plants, using methods approved for the site.
  • Control crimson rosellas and remove European starling nesting material from nest boxes where authorised, because both species compete with the owl for nest sites.
  • Maintain approved rat and cat control, including predator-proofing of nest sites, while managing bait use to reduce the risk of secondary poisoning because the owl eats rats.
  • Include wildfire and cyclone risk in the site management plan because the population is small and vulnerable to stochastic events.

Rehabilitation actions: Success measures and follow-up

  • Inspect restored areas for native plant establishment, weed reduction, retained understorey structure and protection of nest boxes and hollow-bearing trees.
  • Monitor nest-box occupancy, owl detections, breeding attempts, fledging and breeding success during the September to October breeding period and through fledging from December to January.
  • Review predator and nest-competitor records, adapt weed, rat, cat, rosella and starling controls where monitoring shows they are ineffective, and report the results to the relevant land manager and wildlife database.
  • Keep rehabilitation and monitoring in place until the approved success criteria are met and the restored habitat is functioning as a protected part of the local forest system.

Sources