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Chestnut-quilled Rock Pigeon (Petrophassa rufipennis)

The Chestnut-quilled Rock Pigeon is a small, dark pigeon restricted to tropical sandstone escarpments in western Arnhem Land, Northern Territory. It matters on development sites because clearing, blasting, access tracks and disturbance can remove or disrupt the rocky ledges, sandy feeding areas and gorge habitat on which it depends.

Conservation status

Northern Territory, Territory Parks and Wildlife Conservation Act 1976: Near threatened.

Breeding season

A species-specific annual breeding calendar is not provided. The activity pattern below reflects documented field observations and applies a year-round precaution where works affect occupied sandstone escarpment habitat.

Months are January to December. A value of 0 means no documented occurrence, 1 means occurrence or risk is possible or documented without a seasonal peak, and 2 means a documented peak. No month is marked 2 because the supplied documents provide no seasonal breeding or movement data.

  • Local movement and daily activity: No seasonal movement is documented. Birds were located in small groups in the early morning and late afternoon and flew between outcrops, ledges and feeding areas when disturbed.
  • Highest clearing risk: Use a year-round precaution because the breeding calendar is unknown and the species depends on restricted sandstone escarpment habitat. The supplied documents do not support identifying particular high-risk months.

Identification

This is a dark, sooty brown pigeon of rocky escarpments. The chestnut wing patch is the main field mark, but it is usually hidden when the bird is perched.

Adults have dark sooty brown plumage, black lores and pale spots on the head and neck. The chin and throat are whitish, and fine grey lines surround the eye.

The bright chestnut patch on the wing is most obvious when the bird flies. A startled bird may burst from a rocky ledge with loud, clapping wing beats and fly directly up from a gorge.

Wing length: 138 to 155 mm.

Bill length: 11.0 to 14.5 mm.

Weight: 130 to 178 grams.

Identification: Distinguishing it from White-quilled Rock Pigeon

The two species have a similar general appearance and use similar rocky escarpment habitat. The Chestnut-quilled Rock Pigeon is geographically restricted to sandstone country in Arnhem Land and Kakadu.

The chin and centre of the throat are white in the Chestnut-quilled Rock Pigeon. In the White-quilled Rock Pigeon these areas are spotted black and white, with black feathers that have white centres.

The Chestnut-quilled Rock Pigeon has mottled sagittate silvery-grey marks on the head, neck, mantle and upper breast. These areas are more uniformly coloured or only slightly scalloped grey and brown in the White-quilled Rock Pigeon.

Identification: Field signs and survey behaviour

Birds are generally encountered in pairs or small groups. They may walk around open sandy areas between rocky outcrops while feeding, or rest along escarpment ridgelines.

The species initially responded to call playback in one capture study, flying low from the top of an outcrop to a ledge on the other side. Birds quickly became desensitised to playback, so repeated playback is unlikely to be a reliable detection method.

The supplied documents do not describe diagnostic tracks, scats, nests, eggs, calls, roost signs or eyeshine for this species.

  • During a fauna inspection, check rocky ledges, gorge margins, ridgelines and open sandy areas beside outcrops.
  • Watch for birds flushing from ledges or flying low across gaps between rocky outcrops.
  • Treat a flushed pigeon from suitable Arnhem Land sandstone habitat as a potential Chestnut-quilled Rock Pigeon until its wing patch and throat pattern are checked.

Distribution: National and regional range

The species is endemic to the Northern Territory. Its known range is centred on the sandstone escarpments of western Arnhem Land and the Kakadu region.

The Chestnut-quilled Rock Pigeon is known only from the Northern Territory. It is associated with western Arnhem Land sandstone escarpments and has been recorded in the Arnhem Land and Kakadu sandstone country.

The historical specimen localities listed in the supplied material include Katherine Gorge, UDP Falls, El Sherana, Koolpin Creek, Nourlangie, Sawtooth Gorge, Noranda and Mount Brockman.

Australian states and territories: Northern Territory only.

Bioregional setting: Western Arnhem Land and Kakadu sandstone escarpment country.

Known localities in the supplied records: Katherine Gorge, UDP Falls, El Sherana, Koolpin Creek, Nourlangie, Sawtooth Gorge, Noranda and Mount Brockman.

Distribution: Strongholds and population information

The supplied documents do not provide a current population estimate, population trend, home range or confirmed subpopulation assessment for the Chestnut-quilled Rock Pigeon.

The species was studied at rocky outcrops along the north-western Arnhem escarpment, where birds were located in small groups and repeatedly used open sandy feeding areas beside rock outcrops.

Population size: Not reported in the supplied documents.

Population trend: Not reported in the supplied documents.

Home range: Not reported in the supplied documents.

Habitat: Habitat type

This pigeon is closely tied to tropical sandstone escarpments rather than general woodland habitat. The most relevant site features are rocky outcrops, ledges, gorge walls, ridgelines and nearby open sandy ground.

The species occurs exclusively on rocky escarpments in its Northern Territory range. Historical records and field observations place it in rugged sandstone country, including gorges, rocky ridges and outcrops.

The supplied documents do not identify a particular vegetation community, dominant plant species, elevation band or upper climatic limit.

Elevation range: Not reported.

Climate setting: Tropical northern Australia.

Vegetation community: Not specified in the supplied documents.

  • Map and retain sandstone escarpments, gorge walls, rocky ridgelines and ledges within and beside the work area.
  • Inspect open sandy depressions and small clearings between outcrops, as these can be used for feeding.
  • Do not treat apparently sparsely vegetated rock as low-value habitat without checking for pigeons and nearby feeding areas.

Habitat: Structural features

Birds rest on escarpment ridgelines and rocky ledges, and may fly from outcrops across gorges. Feeding observations were concentrated in open sandy areas bordered by rocky outcrops.

At capture sites, net lines were placed about 1 to 2 metres from the edge of the rocky outcrops because disturbed birds flew towards the rocks.

  • Record the location and continuity of rock ledges, outcrop edges, gorge margins and sandy areas adjoining them.
  • Include the immediate area around outcrops in habitat assessments, not only the rock face itself.
  • Avoid placing haul roads, laydown areas or spoil on open sandy ground immediately beside suitable outcrops.

Foraging habitat: Foraging behaviour

The supplied material gives limited information on diet, but confirms ground foraging in small groups around open sandy areas within rocky escarpment habitat.

The species was observed walking about and feeding in small groups among rocky outcrops, particularly in the early morning and late afternoon.

Birds repeatedly searched for food in open sandy areas bordered by rocky outcrops. When disturbed, they flew up towards the adjacent rock ledges.

Diet: Not reported in the supplied documents.

Foraging location: Open sandy areas bordered by rocky outcrops.

Foraging group size: Small groups were observed.

Foraging range: Not reported.

  • Survey open sandy patches, shallow depressions and other sparsely vegetated ground immediately beside sandstone outcrops.
  • Carry out searches in the early morning or late afternoon when birds were most readily located in the field study.
  • Record both feeding observations and the nearby escape ledges, because the feeding area and rocky refuge function together.

Breeding habitat: Breeding information gap

The supplied documents do not provide breeding records or describe nests, eggs, breeding season or parental care for this species.

No species-specific information was supplied on mating, laying, clutch size, incubation, fledging, age at maturity or lifespan.

Until a project-specific breeding assessment is available, treat occupied escarpment habitat, ledges, gorge walls and adjoining feeding areas as potentially important throughout the year.

Breeding season: Not reported.

Clutch size: Not reported.

Incubation period: Not reported.

Age at maturity: Not reported.

Lifespan: Not reported.

  • Ask the project ecologist or relevant Northern Territory wildlife authority to confirm any current breeding records before clearing or blasting suitable sandstone habitat.
  • Search rock ledges, crevices and sheltered gorge locations for breeding activity before works begin, while recognising that the supplied documents do not provide a diagnostic nest description.
  • Avoid repeated disturbance of birds using the same ledge or gorge section, particularly if adults are carrying food or repeatedly entering a crevice.

Sheltering habitat: Ledges, ridgelines and gorges

Rocky escarpments provide the documented resting and escape habitat. The species uses ridgelines and ledges and may rise directly from gorge depths when disturbed.

Birds rest along the ridgelines of rocky outcrops and flush towards rock ledges when approached. They may also ascend directly from the depths of a gorge.

The supplied documents do not give measurements for roost ledges, crevice dimensions, shelter depth or daily roost distance.

Documented shelter features: Rock ledges, rocky outcrops, ridgelines and gorges.

Shelter dimensions: Not reported.

Hollows, burrows and dens: Not reported for this species.

  • Retain rocky ledges, ridgelines, gorge walls and crevices within the work footprint and beside access routes.
  • Keep machinery, people and temporary lighting away from active ledges where birds are repeatedly observed resting or flushing.
  • Inspect rock faces and ledges before drilling, blasting, scaling or earthworks.

Threats: Clearing, earthworks and fragmentation

The species has a restricted distribution and is listed as Near Threatened in the Northern Territory. The clearest project risk is the loss or disturbance of its specialised sandstone escarpment habitat and adjoining feeding areas.

Clearing or damaging sandstone outcrops, gorge margins, ledges, ridgelines and open sandy feeding areas can remove habitat used for resting, escape and foraging.

Roads, tracks, pads and other linear works can divide rocky habitat and increase disturbance around sites where birds move between feeding areas and ledges. The supplied documents do not quantify the species response to fragmentation.

Conservation listing: Near Threatened in the Northern Territory.

EPBC Act: Not listed.

  • Avoid the removal of sandstone outcrops and rock ledges wherever practicable.
  • Keep construction footprints, access tracks, spoil and laydown areas away from sandy feeding patches beside outcrops.
  • Use a pre-clearance inspection and fauna spotter catcher when works affect suitable sandstone escarpment habitat.
  • Stop work and obtain ecological advice if Chestnut-quilled Rock Pigeons are repeatedly flushed from the work area or are using a ledge or crevice.

Threats: Fire, predators, disease and hydrology

The supplied documents do not identify species-specific effects of fire, introduced predators, disease, altered drainage or changed water availability.

These pressures should still be considered where they alter the sandstone escarpment habitat, sandy feeding areas or access to gorge and ledge refuges. Site controls should be based on the project risk assessment and advice from the relevant Northern Territory authority.

  • Prevent avoidable fires, uncontrolled hot works and fuel spills near rocky escarpments and adjoining feeding areas.
  • Do not create drainage, erosion or sediment movement that covers sandy feeding areas or destabilises rock ledges.
  • Record feral predator observations and unusual mortality, but do not assume a species-specific cause without evidence.
  • Limit unnecessary lighting, noise and repeated vehicle movements around occupied gorges and escarpment ridgelines.

Threats: Handling and survey disturbance

The species appeared easily stressed during capture and should be processed promptly and with care. Playback also caused rapid desensitisation after an initial response.

Capture and close approach should therefore be undertaken only by suitably experienced personnel under the project approval and animal ethics requirements.

  • Do not repeatedly flush birds from ledges to obtain an identification or photograph.
  • Use playback sparingly and stop if birds show repeated flight responses or signs of stress.
  • If capture is authorised, process birds promptly and release them at the capture site unless the approved protocol states otherwise.

Survey methodology: 1. Rocky outcrop searches

Survey effort should focus on tropical sandstone escarpments, rocky outcrops, ledges, ridgelines and nearby open sandy feeding areas. The species is endemic to western Arnhem Land and is most detectable when walking suitable rocky habitat in the early morning or late afternoon.

Walk rocky outcrops, escarpment ledges and ridgelines in the early morning or late afternoon, when birds have been observed resting, walking and feeding.

Search in pairs or small groups of observers where safe, and record all birds, flight paths, feeding areas, roosting ledges and likely movement routes.

Expect birds to flush from rocky ledges with loud, clapping wing beats, sometimes flying low towards another rock ledge or ascending from a gorge.

Record the survey date, start and finish time, weather, observer effort, route, habitat feature, number of birds, behaviour and precise location.

Known habitat: Tropical sandstone escarpments, rocky outcrops, ledges, ridgelines and nearby open sandy areas

Most suitable search periods: Early morning and late afternoon

Typical group size: Pairs or small groups

Survey methodology: 2. Call playback and flight observation

Playback can be trialled at suitable rocky outcrops because birds initially responded by flying low over the playback device from an outcrop to a ledge on the opposite side.

Use playback cautiously and record the equipment, call used, start and finish time, location and response.

Do not rely on repeated playback at one site, because the species appeared to become quickly desensitised.

Combine playback with a watch of ridgelines, ledges and gorge margins, because birds may be detected in flight rather than by a sustained approach to the device.

Observed response: Initial response to playback, followed by rapid desensitisation

Observed flight behaviour: Low flight over the playback device between rocky outcrops and ledges

Survey methodology: 3. Targeted capture only where authorised

Use capture only where it is authorised under the applicable wildlife permits and approved project procedures.

If capture is required, place 12 to 18 metre ground nets around an open sandy area bordered by rocky outcrops, with net lines about 1 to 2 metres from the outcrop edge.

Use 210 denier netting with 30 mm mesh, matching the documented field technique for this species.

Locate birds by walking through rocky outcrops in the early morning or late afternoon, or by watching ridgelines where they rest, then wait until a bird is within several metres of a net line before steadily approaching to flush it towards the outcrop and net.

Process captured birds promptly and use experienced handlers, because the species appeared easily stressed during capture.

Do not treat the documented capture result as a population estimate, because the study recorded two birds captured using the ground-net technique.

Net length: 12 to 18 metres

Net placement: About 1 to 2 metres from the rocky outcrop edge

Net specification: 210 denier, 30 mm mesh

Study capture result: Two birds captured using the documented ground-net technique

Survey methodology: Minimum effort and reporting

  • Before fieldwork, map all sandstone escarpments, rocky outcrops, ledges, ridgelines, gorge margins and open sandy areas within the disturbance footprint and adjoining retained habitat.
  • Repeat searches across the early morning and late afternoon periods where access, safety and project timing allow, and state the actual number of observers, search hours, area covered and survey conditions in the report.
  • Treat a non-detection cautiously because the species can remain on rocky ledges and playback responses can decline quickly.
  • Report records, survey routes, photographs and any capture or handling event to the relevant Northern Territory wildlife database or other relevant state or territory wildlife database.
  • Include the species name, Petrophassa rufipennis, the location, date, number of birds, behaviour, habitat and evidence type in each record.

Before habitat disturbance: Avoid and minimise habitat loss

Plan works around the species' dependence on western Arnhem Land sandstone escarpments and rocky outcrops. The main site objective is to retain occupied or suitable rock habitat and the movement routes between retained outcrops.

  • Retain sandstone escarpments, rocky outcrops, ledges, ridgelines, gorge margins and open sandy areas used for feeding wherever practicable.
  • Avoid removing or isolating rock ledges and outcrops that provide resting, escape and movement sites.
  • Retain connected rocky habitat around the disturbance area so birds can move between outcrops and ledges.
  • Keep machinery, laydown areas, access tracks and spoil outside mapped rocky habitat unless the approved design specifically requires entry.

Before habitat disturbance: Approvals and project planning

Supplied conservation status: Not listed under the EPBC Act; Near Threatened in the Northern Territory

Taxon group: Bird

  • Check the current EPBC Act status before works commence, noting that the supplied profile records the species as not listed under the EPBC Act and Near Threatened in the Northern Territory.
  • Confirm all Northern Territory or other jurisdictional wildlife permits, survey approvals, capture permissions and animal welfare requirements with the relevant agency.
  • Prepare a fauna management plan that identifies mapped habitat, survey results, exclusion areas, spotter catcher authority, stop-work triggers, handling arrangements and reporting requirements.
  • Stage clearing so that retained rocky habitat and access between retained outcrops remain available while works proceed.
  • Set work timing to avoid the periods identified as the best field detection periods, unless a project ecologist confirms that the resulting inspection and supervision arrangements are adequate.

Before habitat disturbance: Site preparation

  • Complete a pre-clearance survey of all rocky habitat and adjoining open sandy feeding areas within and beside the work footprint.
  • Mark exclusion areas, rock ledges, ridgelines, gorge edges, feeding areas and movement routes on construction drawings and on the ground.
  • Use exclusion fencing or other clearly visible barriers where they can be installed without damaging rock habitat or blocking required wildlife movement.
  • Brief machinery operators and supervisors on the species' appearance, its chestnut wing patch, likely habitat and the requirement to stop when a bird or occupied habitat is identified.
  • Confirm the location and availability of an authorised wildlife handler, wildlife carer and veterinary pathway before clearing begins.

During habitat disturbance: Daily work controls

Use active supervision whenever works enter or approach sandstone escarpments and rocky outcrops. The fauna spotter catcher should control the interaction between machinery, workers and any bird detected in the work area.

  • Inspect exclusion fencing, signs and habitat boundaries at the start of each workday and after heavy weather or any site change.
  • Keep machinery within approved work limits and maintain clear access for the fauna spotter catcher to inspect rocky outcrops, ledges and open sandy areas.
  • Require the spotter catcher to remain in direct communication with the operator while machinery works near mapped habitat.
  • Use slow, controlled movements near rock edges and stop machinery whenever the spotter catcher cannot see the active work area.
  • Record the date, work area, weather, personnel, machinery, habitat affected, fauna observations and any control failure.

During habitat disturbance: Fauna spotter catcher response

  • The authorised spotter catcher must inspect the work area before disturbance and maintain visual supervision while clearing or construction occurs near suitable rocky habitat.
  • If a Chestnut-quilled Rock Pigeon is found, direct the operator to stop and give the bird time to leave without pursuit where it can move safely to retained rocky habitat.
  • Do not catch, restrain, band, transport or release the bird unless the handler is authorised and the action is covered by the applicable permit and fauna management plan.
  • If relocation is required, use nearby retained rocky habitat that matches the bird's sandstone outcrop setting and is outside the immediate work area, subject to approval by the authorised handler.
  • Obtain veterinary or wildlife carer assistance for an injured or distressed bird, and keep handling to the minimum needed for safety and transport.

During habitat disturbance: Habitat handling and stop-work triggers

  • Stop work if a bird is within the active disturbance area, if a bird is repeatedly flushed from a ledge or outcrop, or if the approved habitat boundary cannot be maintained.
  • Stop work if unrecorded rocky outcrops, ledges, gorge margins, ridgelines or open sandy feeding areas are exposed within the work footprint.
  • Do not move rocks or alter ledges until the fauna spotter catcher and ecologist have checked whether the feature is being used or forms part of connected retained habitat.
  • Treat repeated low flights between outcrops, birds resting on ridgelines, or birds walking and feeding in small groups as evidence requiring review of the work method and exclusion area.
  • Resume work only after the authorised environmental representative has recorded the observation, confirmed the control response and approved the revised work area or method.

After habitat disturbance: Post-clearance inspection

Post-work checks should confirm that retained rocky habitat remains usable and that all fauna incidents and habitat changes have been recorded. Review the controls where birds continue to use the retained escarpment or where works have reduced access between outcrops.

  • Inspect the completed work area and retained rocky habitat for injured, trapped or displaced birds before demobilisation from each work stage.
  • Check that rock ledges, outcrops, ridgelines, gorge margins and open sandy feeding areas identified before works remain intact and accessible.
  • Remove temporary barriers only when the fauna management plan allows their removal and the work area no longer presents a fauna risk.
  • Record any bird sightings, carcasses, injuries, captures, relocations, habitat damage and corrective actions.

After habitat disturbance: Monitoring and reporting

  • Monitor retained rocky habitat during the project and after each clearing stage using the same mapped routes and early morning or late afternoon search periods where practicable.
  • Compare post-work observations with pre-work records, including the number of birds, group observations, flight paths, feeding areas and use of ridgelines or ledges.
  • Submit confirmed records and incident information to the relevant Northern Territory wildlife database or other relevant state or territory wildlife database.
  • Provide the regulator and project environmental officer with survey results, permit records, handling records, stop-work events and corrective actions.

After habitat disturbance: Ongoing controls and offsets

  • Maintain exclusion fencing, habitat markers and machinery restrictions for as long as the fauna management plan requires.
  • Repair any damaged exclusion controls promptly and reassess the work area if birds begin using areas affected by construction.
  • Where residual impacts remain, implement any approved offset, compensatory habitat measure or conservation action required by the project approval.

Rehabilitation actions: Reinstate habitat structure

Rehabilitation should recreate the rocky outcrop setting used by this species rather than relying only on revegetation. The supplied documents identify sandstone escarpments, rock ledges, ridgelines and open sandy feeding areas as the relevant habitat features.

  • Retain and reinstate sandstone rock, stable ledges, rocky outcrops and ridgelines where these features were disturbed by temporary works.
  • Reinstate open sandy areas adjoining retained outcrops where they were used for walking and feeding.
  • Avoid covering rock ledges, gorge margins or movement routes with spoil, mulch, infrastructure or dense plantings.
  • Use locally appropriate native plant species from the surrounding sandstone escarpment community where planting is needed to stabilise disturbed ground, but do not plant over open rocky or sandy feeding areas.

Rehabilitation actions: Fire, weeds and predators

  • Control weeds and prevent weed establishment around rehabilitated rocky outcrops, ledges and open sandy feeding areas.
  • Apply fire management that maintains the structure of sandstone escarpment habitat and follows the approved local fire regime and agency advice.
  • Manage introduced predators and other disturbance pressures where they are identified as a project impact and where an approved control method is available.

Rehabilitation actions: Success measures and monitoring

  • Inspect rehabilitation after each work stage and during follow-up monitoring to confirm that rock features are stable, open sandy areas remain available and access between retained outcrops has not been blocked.
  • Use repeat early morning and late afternoon searches to document whether Chestnut-quilled Rock Pigeons return to or continue using retained and rehabilitated habitat.
  • Record birds walking or feeding in small groups, resting on ridgelines, or flying between outcrops and ledges as habitat-use indicators.
  • Set project-specific completion criteria for rock stability, access between outcrops, weed control, erosion control and confirmed use by the species, and report results to the relevant approval authority.

Sources