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Australian Gull-billed Tern (Gelochelidon nilotica)

The Australian Gull-billed Tern is a thick-billed tern of inland and coastal wetlands, estuaries, beaches and flood-affected country. On works sites, shallow water, exposed mud or sand, islands and wetland margins may support feeding, roosting or colonial breeding birds. It is least concern in Australia, but is a colonial breeder and a CAMBA-listed migratory species under the EPBC Act, so breeding places and significant impacts require careful assessment.

Conservation status

Commonwealth, EPBC Act 1999: Listed migratory. Listed under CAMBA. Listed migratory species are a matter of national environmental significance, so a significant impact needs referral.

Queensland, Nature Conservation Act 1992: Special least concern. A least concern bird covered by an international migratory bird agreement. Tampering with its breeding place needs a high risk species management program.

Western Australia, Biodiversity Conservation Act 2016: Specially protected (migratory).

Queensland, Nature Conservation Act 1992: Colonial breeder. Least concern in Queensland, but it breeds in colonies, so tampering with a breeding place needs a high risk species management program rather than the low risk program.

Migration and breeding season

Australian Gull-billed Terns are present in Australia throughout the year, but numbers and locations shift seasonally. Australian breeding is recorded mostly from September to January, while birds move between northern and southern Australia and may also disperse to New Guinea and Indonesia.

Breeding mode: Colonial breeder. Australian breeding occurs at scattered sites, and colonies may contain many nests concentrated in a small area.

Breeding places: Large, often ephemeral, inland lakes and swamps, especially exposed islands, banks and spits of dry mud or sand. Sites may be bare or sparsely vegetated with grass, reeds, rushes or samphire.

Clutch size: Not recorded.

Incubation: Not recorded.

Fledging and dependence: Not recorded.

Colony size: Not recorded. Groups may be concentrated at suitable wetland islands, banks, sandflats or mudflats.

Recognising and protecting an active breeding place: Look for adults repeatedly defending or circling a site, birds sitting low on bare ground or sparse vegetation, eggs, chicks, alarm calls, distraction behaviour and regular movement between the colony and nearby feeding areas. Treat the whole island, bank, spit or wetland margin as sensitive. Keep clearing, earthworks, vehicles, machinery, people, dogs and loud activity outside the nesting period where practicable, and use a site-specific buffer set by the project ecologist or regulator. Do not enter or alter a colony without the required approvals.

Seasonal movements, breeding activity and colony use can vary with rainfall, flooding, wetland water levels and local conditions, so pre-clearance checks are needed even outside the main September to January breeding period.

  • Breeding overseas, timing varies by region: Gull-billed Terns breed in several regions outside Australia, but the timing of overseas breeding is not uniform and should not be used to set an Australian work window.
  • Southward arrival and dispersal to southern Australia: Birds move towards southern Australia for the warmer months, with arrival timing varying between years and regions.
  • Non-breeding presence in Australia: The species is present somewhere in Australia year-round, using wetlands, floodwaters, estuaries, saltmarshes, lagoons, beaches and other shallow-water habitats.
  • Northward departure to northern Australia and beyond: Many birds move north for winter, and substantial numbers may continue to New Guinea or Indonesia, but departure timing is not fixed.
  • Breeding in Australia: Australian breeding occurs mostly from September to January, at scattered inland wetland sites and occasionally suitable coastal or estuarine areas.
  • Highest clearing risk: The highest risk is September to January, when clearing or construction can destroy eggs, chicks, nests and active colonies, although active sites should be checked before works at any time.

Identification: Appearance

The Australian Gull-billed Tern is a medium-sized tern with a distinctive thick, short bill. Identification is easiest when the bird is perched on a wetland margin, mudflat, sandbank or beach.

Adults are mainly white. In breeding plumage, the black crown extends from the bill to the nape, with a grey back and upper wings and darker flight feathers.

The bill and legs are black, and the iris is dark brown. Sexes are similar.

In non-breeding plumage, the head is mainly white, with a brownish-grey streaked crown and dull black ear coverts. Immature birds resemble non-breeding adults. Juveniles have shoulders mottled grey and brown.

Bill: Short, thick and gull-like, rather than the fine bill of many other terns.

Body measurements: Use a field guide or approved identification reference for measurements. Do not rely on size alone in poor viewing conditions.

Identification: Calls and similar species

Species-specific call descriptions are not available in the material used for this profile. Record vocal activity where possible, but confirm identification from shape, plumage, bill and habitat.

Compare carefully with other terns at the site. The thick black bill is a useful feature, especially when combined with the heavier build and broad-headed appearance.

  • Check the bill shape before relying on plumage colour.
  • Look for the black hood in breeding plumage.
  • Use photographs or a telescope where the bird is distant or in flight.

Identification: Field signs

Look for groups standing or loafing on exposed mud, sand, spits, bars, islets or low saltmarsh. Repeated use of the same open margin may indicate a roost or a nearby breeding area.

Nests may be simple scrapes on bare mud, sand or sparsely vegetated ground. There may be little nest material, so the presence of adults repeatedly defending or returning to one small area is more useful than searching for a conspicuous nest.

  • Repeated alarm calls or circling adults.
  • Adults standing upright and watching approaching people or machinery.
  • Birds leaving the ground together when workers approach.
  • Eggs, chicks, scrape nests or concentrated droppings on open substrates.

Distribution: Australian range

In Australia, the Australian Gull-billed Tern occurs in inland wetlands, coastal wetlands and sheltered coastal areas. It is widespread but dispersive, and local numbers can change with water conditions and seasonal movement.

The species is mapped in New South Wales, the Northern Territory, Queensland, South Australia, Tasmania, Victoria and Western Australia. It is common and widespread in parts of south-eastern Australia, but is only a vagrant in Tasmania in some accounts.

Records include the Pilbara and Ningaloo coast in Western Australia, Port Albert and Port Welshpool in Victoria, the Coorong and Lower Lakes in South Australia, and beaches, coastal rivers and wetlands in New South Wales.

  • Inland lakes, swamps and floodplains.
  • Coastal lagoons, estuaries and river deltas.
  • Beaches, mudflats, sandflats and saltmarsh.
  • Irrigated croplands, grasslands and sewage farms where suitable shallow water is present.

Distribution: Overseas range

The species occurs on all continents except Antarctica. In the Australasian region, some birds move beyond Australia to New Guinea and possibly Indonesia.

Distribution: What a site record means

A single bird may be a transient visitor, while repeated records can indicate a reliable feeding or roosting area. Do not dismiss low numbers where the site contains suitable wetland edges or exposed islands.

Map the bird location, direction of movement, water level, tide, habitat used and any nearby roost or breeding activity.

Habitat: Wetland and coastal features

Look for open water and exposed wetland edges rather than dense forest. The species uses both freshwater and saline environments, and habitat availability can change quickly after rain, flooding, drying or water-level management.

Suitable areas include shallow freshwater swamps, brackish or salt lakes, lagoons, inundated ground, saltpans, claypans, saltmarsh, rivers and associated floodplains.

Coastal habitat includes sheltered embayments, estuaries, river deltas, tidal mudflats, sandflats, beaches and sandy coastal margins.

  • Open water with shallow margins.
  • Bare or sparsely vegetated mud and sand.
  • Low saltmarsh, samphire, reeds or rushes near water.
  • Islands, banks, bars, spits and other elevated areas surrounded by wet ground.

Habitat: Site features to inspect

During pre-clearing inspections, check wetland margins, temporary pools, drainage lines, floodplain depressions, irrigation areas and isolated islands. Include nearby land that may be used when water levels change.

Inspect both the proposed footprint and the surrounding wetland system. A construction area may not contain birds on the survey day but may still support birds when water levels or food availability change.

  • Water-level gauges, regulators, pumps and diversion structures.
  • Access tracks crossing floodplains or wetland margins.
  • Stock dams, evaporation ponds and sewage treatment wetlands.
  • Low islands and exposed banks that become available as water recedes.

Habitat: Water and flooding

Flooding can create shallow feeding habitat and expose or remove mud and sand margins. Drying can concentrate prey and birds, but may also remove safe roosting or breeding areas.

Plan water management so that works do not suddenly inundate nests, isolate chicks, remove exposed margins or strand birds from feeding areas. Review conditions after major rainfall and before changing levels.

Foraging habitat: Foraging places

The Australian Gull-billed Tern usually feeds in shallow water or along the edge of water. It takes prey from the surface of water, exposed mud or sand, and occasionally plunges into water.

Inspect shallow wetlands, mudflats, sandflats, saltpans, claypans, saltmarsh, floodwaters, river edges, estuaries, beaches and sheltered lagoons.

The species may also forage over irrigated croplands, grasslands, sewage farms and ploughed fields when these areas hold suitable prey or shallow water.

  • Wet margins with exposed mud or sand.
  • Recently flooded depressions and floodplain pools.
  • Tidal flats and estuarine margins.
  • Sheltered coastal water rather than open ocean.

Foraging habitat: Diet and feeding behaviour

The diet includes insects, annelids, crustaceans, fish and small vertebrates such as mice and skinks. Young waterbirds may occasionally be taken.

Feeding methods include hawking insects, dipping from the water surface and rarely plunging into water.

  • Watch for repeated low passes over shallow water.
  • Look for birds landing on exposed mud or sand between feeding flights.
  • Record feeding areas separately from roosts and breeding places.

Foraging habitat: Construction considerations

Keep sediment, spoil, concrete washout, hydrocarbons and litter out of shallow water and wetland margins. Avoid creating steep, contaminated or permanently turbid edges that reduce feeding opportunities.

Where lighting is needed near coastal or wetland habitat, use the minimum safe lighting, direct it away from water and birds, shield upward light and switch off non-essential lights when not required.

Breeding habitat: Breeding places

Australian breeding is poorly documented, but breeding occurs at scattered wetland sites, mostly from September to January. Treat suitable open wetland islands, banks and spits as potential breeding habitat during this period.

Breeding sites include large, often ephemeral, inland lakes and swamps. Birds may nest on exposed islands, banks and spits of dry mud or sand, and occasionally on rocks.

The substrate may be bare or sparsely covered by dry grass, reeds, rushes or samphire. These sites can look unproductive and may be easy to overlook during a walkover.

  • Open islands surrounded by water or wet mud.
  • Dry mud or sand spits and banks.
  • Low rocky platforms near suitable water.
  • Sparse grass, reeds, rushes or samphire rather than dense woodland.

Breeding habitat: Recognising an active breeding place

Look for adults repeatedly returning to one open area, defending a small patch, carrying food, alarm calling or circling over an approaching person. Eggs and chicks may be difficult to see because nests are low scrapes on bare or sparsely vegetated ground.

A group that flushes from an island or bank should be investigated from a distance with binoculars or a telescope. Do not walk onto the site to confirm breeding.

  • Adults sitting low or crouching on a scrape.
  • Chicks sheltering motionless against mud, sand or sparse vegetation.
  • Broken eggshells, small scrape nests or concentrated droppings.
  • Repeated flushing from the same island, bank, spit or wetland margin.

Breeding habitat: Timing of works

Where practicable, schedule clearing, earthworks, vegetation removal and water-level changes outside the main Australian breeding period of September to January. Local conditions may extend the risk period, especially after flooding or when suitable habitat forms late in the season.

If works must occur during the breeding period, complete a targeted inspection shortly before works and establish an ecologist-approved exclusion area around any active breeding place.

Sheltering habitat: Roost features

Roosting birds need open, relatively undisturbed ground close to water. Roosts may be used by feeding birds, migrants, local residents or birds moving through the area.

Typical roosts are exposed muddy or sandy banks, mudflats, sandflats, bars, spits and islets. Low saltmarsh or other sparse vegetation may be present, but dense cover is generally less suitable.

The species has been recorded roosting on sandy coastal areas, including parts of the Ningaloo coast.

  • High-tide or flood refuges above shallow water.
  • Open islands and sandbars with clear views of approaching predators.
  • Wetland edges close to feeding areas.
  • Quiet coastal beaches, estuarine margins and lagoons.

Sheltering habitat: Disturbance and flushing

People, dogs, vehicles, boats, aircraft, machinery, sudden noise and low-flying drones can flush roosting birds. Repeated flushing uses energy, interrupts feeding and may expose birds to predators or high temperatures.

There is no single species-specific disturbance distance that should be applied at every site. Start well back, observe behaviour, and increase the separation if birds become alert, walk away, call repeatedly or take flight.

  • Approach from outside the line of sight where possible.
  • Use existing tracks and avoid walking through open roost habitat.
  • Keep dogs leashed and prevent access to islands, banks and spits.
  • Stop work and seek ecological advice if birds repeatedly flush.

Sheltering habitat: Night works and lighting

Artificial light can displace birds from roosts, alter feeding behaviour and increase exposure to predators or collisions. Keep lights away from roosting and nesting beaches, wetland edges and flight paths.

Use downward-directed, shielded lights with the lowest practical intensity. Turn off non-essential lights when work is complete and use timers or motion controls where safe.

Colonies and breeding places: What a colony looks like

The Australian Gull-billed Tern is treated as a colonial breeder. Colonies can concentrate many breeding birds in a small area, so damage to one island, bank or wetland margin may affect a substantial part of the local population.

A colony may be a group of adults nesting close together on an exposed island, mud or sand bank, spit, rock platform or sparsely vegetated wetland margin. Nests can be low scrapes and may be difficult to distinguish from the surrounding substrate.

For this species, the most relevant breeding places are inland lake and swamp islands, banks and spits. More generally, colonial waterbirds may also use reedbeds, lignum, wetland trees, riverbanks, cliffs, culverts, bridges or caves, but these should not be assumed to be Gull-billed Tern breeding sites without supporting evidence.

  • Many adults standing or flying from one small area.
  • Synchronous flushing when a person, vehicle or boat approaches.
  • Alarm calls, defensive flights or adults carrying food.
  • Eggs, chicks or several scrapes within an open substrate.

Colonies and breeding places: Colony size and site fidelity

Species-specific colony sizes and repeat-use rates are not established for this profile. A colony may be small in one season and much larger in another because the species is dispersive and breeding habitat can be ephemeral.

Treat a breeding site as potentially important even when only a few birds are present. Check historical records, nearby wetlands and seasonal water conditions before approving works.

Colonies and breeding places: Buffers and work controls

There is no fixed species-specific buffer distance for every colony. Set a no-entry buffer with a qualified ecologist after considering nest visibility, terrain, access routes, noise, vibration, machinery height, flight paths and the likelihood of flushing.

Keep works outside the nesting period where practicable. Do not drive through a colony, launch boats beside it, land on an island, remove screening vegetation or alter water levels without site-specific ecological advice.

  • Mark the buffer on plans and on the ground.
  • Use spotters where plant operates near the buffer.
  • Keep workers, vehicles, dogs, boats and drones outside the exclusion area.
  • Inspect the colony from a distant vantage point rather than entering it.

Colonies and breeding places: Flooding and water management

Water levels can expose or inundate breeding islands, banks and feeding margins. Rapid changes may flood nests, separate chicks from adults or remove the open mud and sand used by the colony.

Coordinate pumping, drainage, dam filling, drawdown and floodplain works with an ecologist. Maintain suitable access to shallow feeding areas and avoid directing sediment or polluted water into the colony or its foraging habitat.

Queensland regulatory trigger: In Queensland, tampering with the breeding place of a least concern colonial breeder requires a high risk species management program under the Nature Conservation (Animals) Regulation 2020.

Migration and seasonal presence: Seasonal movement in Australia

The Australian Gull-billed Tern includes both resident breeding birds and migratory non-breeding birds. Seasonal presence can therefore vary between regions and between years, especially where wetland conditions change.

The species is nomadic and migratory in the Australasian region. It generally moves to northern Australia in winter and to southern Australia in summer.

Australian breeding occurs mostly from September to January. Exact arrival, departure and passage months vary by region and are not sufficiently defined for a single national survey window.

  • Northern Australia is more likely to support birds during winter.
  • Southern Australia is more likely to support birds during summer.
  • Wetland flooding can attract birds outside expected seasonal patterns.

Migration and seasonal presence: Where birds go outside Australia

Substantial numbers may migrate from Australia to New Guinea and possibly Indonesia. The species also occurs widely overseas, including in Asia, Europe, Africa and the Americas.

Migration and seasonal presence: Important habitat and legal checks

Important habitat in Australia includes active breeding places, regularly used communal roosts, shallow wetland and estuarine feeding areas, and habitat that connects roosts, breeding sites and feeding areas.

The species is migratory under the EPBC Act through CAMBA. An action likely to have a significant impact on the species or its important habitat may require referral under the EPBC Act.

  • Map flight paths between wetlands, roosts and feeding areas.
  • Consider seasonal use, not only birds present during the initial survey.
  • Assess collision risk where tall structures, cranes, powerlines or wind turbines are proposed.
  • In Queensland, CAMBA-listed birds are special least concern animals, and tampering with a breeding place requires a high risk species management program.

Threats: Disturbance and breeding-place damage

Most work-site risks relate to disturbance, loss of shallow wetland habitat, changes to water levels and collisions. Manage the whole wetland system, not only the point where birds are seen.

Clearing, earthworks, vehicles, boats, dogs, people, drones, vibration and noise can flush adults from nests or roosts. Walking onto islands or banks can crush eggs, chicks and scrape nests that are hard to see.

Use exclusion zones, controlled access, site induction and a stop-work process. Have an ecologist inspect any area where adults repeatedly flush or show defensive behaviour.

Threats: Habitat loss and water changes

Filling wetlands, draining floodplain depressions, removing mud or sand margins, compacting banks and increasing sediment can reduce feeding and roosting habitat. Poorly timed flooding or drawdown can destroy nests or remove shallow feeding areas.

Retain wetland edges, islands, bars, spits and low saltmarsh where possible. Keep spoil, sediment, concrete washout and pollutants out of watercourses and wetland margins.

Threats: Lighting and collision risk

Artificial light can displace birds from roosts and alter nocturnal movements. Tall structures, cranes, powerlines, bridges and wind turbines can create collision hazards, particularly where birds move between wetlands or along coastal corridors.

Use shielded, downward-directed lighting and switch off non-essential lights. Map flight activity and consider collision risk early in the design of tall infrastructure.

  • Avoid lighting roosting and nesting beaches or wetland islands.
  • Use the minimum number and intensity of lights required for safety.
  • Prefer warm or amber lighting where consistent with safety requirements.
  • Keep temporary lighting low, targeted and time limited.

Threats: Predators and introduced species

Foxes, cats, pigs and other predators can reach colonies, especially where access tracks, causeways or low water levels connect islands to land. European red fox predation is recognised in national threat planning for this species.

Do not create easy predator access to colonies. Control food waste, secure site compounds, manage weeds and inspect causeways and temporary access routes for predator movement.

  • Keep construction waste and food scraps secured.
  • Avoid leaving open trenches or materials that shelter feral predators.
  • Report fox, cat or pig activity near breeding places.
  • Use approved fauna and pest management procedures before any control action.

Survey methodology: 1. Desktop assessment

Survey the Australian Gull-billed Tern as a mobile wetland and coastal waterbird. Use repeated observations across the seasons and cover both potential feeding areas and elevated or exposed roosting and breeding places.

Map wetlands, lakes, lagoons, floodplains, rivers, estuaries, saltmarsh, mudflats, sandflats, beaches, islands, sandbanks and exposed wetland margins.

Check records from wildlife databases, local bird groups, landholders and previous project surveys. Look for records of feeding, roosting, breeding plumage, nesting or groups using the same site.

Treat freshwater and saline habitat as relevant. The species can occur inland and along the coast, and may move between northern and southern Australia seasonally. Review the need for an EPBC Act referral where the action could significantly affect a listed migratory species.

  • Map all suitable habitat within and around the work area.
  • Identify links between wetlands, waterways, roosts and likely flight paths.
  • Check whether the site contains an island, bank, spit, mudflat or sparsely vegetated wetland feature suitable for breeding.
  • Record nearby lighting, powerlines, towers, wind turbines, roads, people, dogs and other disturbance sources.

Survey methodology: 2. Field detection

Use a telescope or binoculars from outside the habitat where possible. Search shallow water, exposed mud and sand, wetland edges, saltmarsh, estuarine margins, beaches, islands, bars and spits.

Look for birds feeding at the water edge, flying between wetlands, resting in groups, defending a site, carrying nesting material, or showing breeding plumage. A thicker black bill, black legs and a dark breeding crown help distinguish the species from other terns.

Survey from concealed or distant vantage points. Do not walk onto islands, sandbanks or wetland margins that may hold nests or chicks until the area has been assessed by a suitably experienced ecologist.

  • Use quiet, slow approaches and avoid repeatedly flushing birds.
  • Survey likely roosts around high tide where tidal habitat is present, ideally within two hours either side of high tide.
  • Survey exposed feeding areas around low tide where tidal habitat is present, ideally within two hours either side of low tide.
  • Repeat surveys in suitable weather. Delay or repeat work after heavy rain, strong wind or poor visibility.
  • Include surveys during the Australian breeding period, mostly September to January, and during periods when migratory birds are expected at the site.

Survey methodology: 3. Survey effort and records

Use several visits rather than relying on one inspection. The number and timing of visits should reflect habitat quality, previous records, the proposed disturbance and advice from the relevant regulator or a qualified ecologist.

Record the full extent of each observation. A small number of birds can still indicate a regularly used roost, feeding area or breeding place.

  • Record date, start and finish time, tide state where relevant, weather, observers and observation conditions.
  • Record the number of birds, age or plumage where possible, behaviour, flight direction and whether birds were flushed.
  • Map feeding areas, roosts, nests, chicks, territorial behaviour, flight paths and areas avoided by the birds.
  • Photograph habitat and birds only when this can be done without causing disturbance.
  • Record all disturbance, including people, vehicles, dogs, boats, aircraft, lighting and noise.
  • Report observations of breeding, roosting or repeated use to the project ecologist before works proceed.

Before habitat disturbance: 1. Approvals and permissions

Plan the work around the bird’s use of wetlands, coastal margins and breeding places. Avoidance is the first option, especially where a colony, active nest or regularly used roost is present.

Confirm the legal status of the proposed action before clearing, construction, dredging, water management or lighting works begin. The Australian Gull-billed Tern is listed as a migratory species under the EPBC Act through CAMBA and is also listed as marine under the Act.

Refer the action under the EPBC Act if it is likely to have a significant impact on the species or other matters of national environmental significance. Obtain any required state or territory permits, approvals and wildlife authorisations.

In Queensland, obtain advice from the administering department before tampering with a breeding place. The species is a colonial breeder and a CAMBA listed special least concern animal, so a high risk species management program is required where the Queensland rules apply.

  • Check the EPBC Act referral position and retain the decision, referral outcome or approval on the project file.
  • Check state and territory wildlife, planning, waterway, wetland and clearing requirements.
  • Use a suitably qualified ecologist to prepare any species management plan or breeding place assessment.
  • Do not rely on least concern status as permission to disturb a colony or breeding place.

Before habitat disturbance: 2. Avoidance and timing

Keep clearing, earthworks, vehicle access, drilling, piling, dredging and noisy construction away from active colonies and breeding places. Schedule works outside the breeding period where practical. Australian breeding occurs mostly from September to January, but local conditions and water levels can alter use of a site.

Allow for seasonal movement. Birds may move to northern Australia in winter and to southern Australia in summer. Migratory birds may also pass through or use the site outside the main breeding period.

Protect feeding and roosting habitat as well as nests. A project can affect the lifecycle of the species by removing shallow water, mudflats, islands, banks, saltmarsh or safe roosts.

  • Retain wetland edges, exposed banks, islands, spits, mudflats and sparsely vegetated breeding habitat where possible.
  • Keep works outside the nesting period where practical, based on local survey results rather than calendar dates alone.
  • Maintain water levels and natural flooding patterns where water management is part of the project.
  • Avoid sudden drawdown, inundation, drainage or isolation of wetland habitat during breeding.
  • Turn off non essential lighting near wetlands, beaches, roosts and nesting areas.

Before habitat disturbance: 3. Pre clearance survey and buffers

Complete a final pre clearance inspection shortly before work starts and again if work is delayed or the site changes. Search all wetland islands, banks, spits, sandbars, mudflats, reedbeds, saltmarsh and nearby roosts.

An active breeding place may contain adults repeatedly defending one area, nests or eggs on bare or sparsely vegetated ground, chicks, recently fledged young, alarm behaviour, repeated carrying of food or nesting material, or adults repeatedly flying to and from one location.

Set a site specific exclusion buffer around an active colony, nest or roost. There is no single distance that suits every site. The buffer must account for visibility, terrain, noise, machinery, access routes, flight paths and the risk of flushing birds.

  • Mark the exclusion area on plans and on the ground.
  • Use fencing, signs and controlled access to keep people, vehicles, dogs and machinery out.
  • Keep workers outside the buffer until the ecologist and regulator confirm that the place is no longer active or that the approved controls are adequate.
  • Recheck the buffer after rain, flooding, water level changes or a prolonged work interruption.
  • Do not enter a colony to count nests unless the survey has been specifically planned and authorised.

Before habitat disturbance: 4. Induction and site controls

Brief every worker, subcontractor, boat operator and machinery operator before entering the work area. Explain that colonies can hold a large share of the local population and that repeated disturbance can cause abandonment, egg cooling, chick separation or predator exposure.

Give the spotter catcher and site supervisor authority to stop work. Make the stop work process clear before machinery arrives.

  • Show workers photographs or maps of the species, active breeding places, roosts and exclusion zones.
  • Set speed limits and access routes away from wetland margins and roosts.
  • Prohibit recreational access, dogs and unnecessary vehicle movement near wetland habitat.
  • Use downward facing, shielded lighting with the lowest practical intensity.
  • Keep a contact list for the project ecologist, wildlife regulator, veterinarian or wildlife carer and emergency services.
  • Record the induction and attendance.

During habitat disturbance: 1. Sequential clearing

Use a staged and closely supervised work method. Stop immediately if birds show repeated flushing, defensive behaviour, injury, nesting activity or use of a previously unidentified breeding place.

Clear in small stages from the least sensitive edge towards already disturbed ground. Retain wetland margins, islands, banks, mudflats, saltmarsh and roosting features until the ecologist confirms that they can be disturbed.

Have the spotter catcher inspect each stage before machinery enters. Use quiet plant where practicable and keep machinery, workers and vehicles within approved access areas.

  • Remove loose materials and rubbish that could attract predators or obstruct birds.
  • Check vegetation, ground depressions, banks, sandbars, culverts, bridges and structures before disturbance.
  • Pause between stages so birds can move away without being trapped or channelled towards traffic.
  • Do not chase, herd or repeatedly flush birds from the work area.
  • Stop work if a bird is unable to leave safely or if birds repeatedly return to the same location.

During habitat disturbance: 2. Active colony, nest or roost response

If an active breeding place, colony, nest, eggs, chicks or a regularly used roost is found, stop work in the immediate area. Keep people and machinery back and prevent further disturbance while the site is assessed.

A colony can be on an exposed island, bank, spit, sand or mud surface, or among sparse grass, reeds, rushes or samphire. Do not assume that a site is inactive because it contains few birds during one visit.

The ecologist must reassess the exclusion buffer, work method, timing and approval conditions. Contact the relevant regulator if the approved plan does not cover the situation.

  • Mark the location from outside the site without entering the colony.
  • Keep aircraft, drones, boats, vehicles, dogs and pedestrians away.
  • Do not touch eggs, chicks, nests or nesting material unless authorised under the relevant approval.
  • Do not relocate a nest, colony or roost without written approval and specialist direction.
  • Resume work only after the site is cleared by the authorised ecologist and any required regulator has been notified.

During habitat disturbance: 3. Handling and injured animals

Only an authorised and trained person may handle an Australian Gull-billed Tern. Most birds should be left where they are if they can move or fly safely. Handling can cause additional stress and may separate a chick from its parents.

If a bird is injured, trapped or unable to fly, stop nearby work and reduce noise. Keep people, vehicles and predators away while the authorised wildlife responder is contacted.

  • Do not feed the bird or give it water unless directed by a wildlife carer or veterinarian.
  • Use a clean, ventilated container only when an authorised person directs capture.
  • Keep the container dark, quiet and secure, away from machinery, heat and direct sunlight.
  • Record the location, time, condition, photographs, actions taken and destination.
  • Notify the project ecologist and the relevant wildlife authority in accordance with the approval conditions.

During habitat disturbance: 4. Incident records and stop work

Treat a flushed colony, injured bird, nest discovery, collision or unauthorised entry into a buffer as an environmental incident. The site supervisor must secure the area and notify the project ecologist.

Keep records that allow the event to be reviewed and reported.

  • Record the species, number of birds, behaviour and exact location.
  • Record the activity underway, machinery, noise, lighting, weather and duration of disturbance.
  • Record who stopped work, who attended, advice received and when work resumed.
  • Preserve photographs, maps, GPS points and relevant approval documents.
  • Report incidents within the time required by the approval, permit or management plan.

After habitat disturbance: 1. Post clearance checks

Do not treat the end of physical clearing as the end of risk. Check the work area, nearby wetlands and access routes for stranded birds, damaged breeding places, changed water conditions and ongoing disturbance.

Inspect each completed work area and its margins for birds, nests, chicks, injured animals, exposed eggs, entanglement hazards and newly isolated wetland habitat.

Check areas below powerlines, towers, cranes and other structures for collision victims where the project creates a strike risk.

  • Complete checks before demobilisation from each work stage.
  • Search culverts, drains, temporary fencing, trenches, stockpiles and sediment controls.
  • Remove temporary hazards that could trap or injure birds.
  • Confirm that exclusion fencing and signs remain effective where habitat is retained.
  • Record all negative findings as well as animals found.

After habitat disturbance: 2. Reporting and compliance

Prepare a close out record for the project ecologist and regulator where required. Include survey results, incidents, approvals, mitigation measures and any changes to habitat or water management.

Report any death, injury, colony disturbance or unauthorised breeding place interference under the relevant approval and permit conditions.

  • Update the project map with final disturbance areas and retained habitat.
  • Provide bird numbers, behaviour, locations and photographs from pre work and post work checks.
  • Document all stop work events and responses.
  • Record lighting changes, water level changes, rehabilitation actions and outstanding risks.
  • Retain records for the period required by the approval or environmental management system.

After habitat disturbance: 3. Monitoring and relocated animals

Monitor retained wetlands, roosts and breeding places for signs of continued use. Monitoring should cover the period specified by the approval and should be extended when birds continue to use the site or when habitat has changed.

Do not release or relocate a bird without advice from an authorised wildlife carer, veterinarian or regulator. A relocated bird must be recorded with its capture point, release point, condition and release decision.

  • Check whether birds return to feeding, roosting or breeding areas.
  • Look for repeated flushing, reduced use, abandoned nests, dead birds and predator activity.
  • Inspect water levels and wetland connections after rainfall, flooding, pumping or drainage.
  • Review monitoring results with the project ecologist before removing controls.
  • Escalate unexpected impacts and revise the work method if required.

After habitat disturbance: 4. Incident review

Review every incident with the supervisor, spotter catcher, ecologist and relevant contractor. Use the review to improve buffers, access, lighting, timing and induction content for later work stages.

Pay particular attention to incidents that show a colony or roost was larger or more sensitive than expected.

  • Identify the cause of the incident and the control that failed.
  • Check whether survey timing, weather, tides or water levels affected detection.
  • Update maps, risk assessments, inductions and stop work triggers.
  • Share lessons with all crews before the next work stage.
  • Record regulator advice and implement it before work restarts.

Rehabilitation actions: 1. Wetland and roost habitat

Rehabilitate habitat that supports feeding, roosting and breeding. Aim to restore natural wetland function rather than replacing a breeding place with an artificial structure that the species may not use.

Reinstate shallow water, wetland edges, mudflats, sandflats, exposed banks, islands, spits and low saltmarsh where these features were disturbed. Retain a mosaic of open ground and sparse vegetation rather than allowing dense growth across all suitable surfaces.

Use locally appropriate materials and landforms. Prevent erosion and sediment movement into shallow feeding areas and wetland margins.

  • Reconnect natural drainage and floodplain flows where the project altered them.
  • Avoid sudden changes in water level during the breeding period.
  • Retain safe, low disturbance roosts above normal water levels.
  • Keep stockpiles, access tracks and fences away from restored wetland margins.
  • Design rehabilitation so birds can see approaching people, vehicles and predators.

Rehabilitation actions: 2. Artificial breeding or roost structures

Nest boxes and bat boxes are not a general replacement for this species. The Australian Gull-billed Tern usually breeds on open ground such as exposed islands, banks, spits, sand or mud, sometimes with sparse grass, reeds, rushes or samphire.

Use an artificial nest site, island, sandbank or roost structure only where a qualified waterbird ecologist has developed a site specific design and the regulator has accepted it. Do not install boxes or enclosed shelters as a substitute for open wetland habitat.

  • Prioritise protection and restoration of natural breeding and roosting places.
  • Assess flood levels, predator access, visibility, substrate, vegetation and human disturbance before creating an artificial site.
  • Keep artificial sites away from regular machinery routes, lighting and public access.
  • Inspect artificial sites for erosion, weeds, predators and unwanted vegetation.
  • Remove or modify a structure if monitoring shows that it attracts predators or causes repeated disturbance.

Rehabilitation actions: 3. Weeds, predators and water

Control weeds without disturbing active nests or roosts. Dense weeds can remove the open ground used for nesting and feeding, while poorly timed spraying or machinery can flush birds.

Manage feral cats, foxes, pigs and other predators under the approved environmental plan. Predator control must be lawful and coordinated with the land manager.

Maintain suitable water conditions for shallow feeding and wetland use. Consider both flooding and drying when setting water management rules.

  • Use local native plants suited to the wetland and salt conditions.
  • Remove invasive plants before they form dense cover on open breeding surfaces.
  • Keep chemicals, sediment and contaminated water out of wetlands and estuaries.
  • Inspect restored habitat after floods, drought, pumping and major storms.
  • Record predator signs, water levels, vegetation cover and wetland connectivity.

Rehabilitation actions: 4. Lighting and long term monitoring

Keep rehabilitation areas dark and quiet. Artificial light can displace birds from roosts and alter nocturnal movement, while noise and repeated access can reduce use of otherwise suitable habitat.

Monitor restored habitat through at least the relevant breeding and seasonal movement periods. The monitoring period and methods should match approval conditions and the scale of the action.

  • Direct lights away from wetlands, beaches, roosts, islands and restored habitat.
  • Use shielding, the lowest practical intensity and timers or motion controls for lights that cannot be removed.
  • Record bird presence, numbers, feeding, roosting, breeding behaviour and flight paths.
  • Inspect for collision victims around new structures and lighting.
  • Compare results with pre work records and adjust water, vegetation, access or lighting controls when use declines.

Sources