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Blue-billed Duck (Oxyura australis)

The Blue-billed Duck (*Oxyura australis*) is a small, almost wholly aquatic diving duck of deep permanent wetlands, lakes and swamps in southern and eastern Australia. It is listed as Vulnerable in New South Wales and Victoria, and development can affect it through wetland drainage, loss of dense nesting vegetation, water-level changes, disturbance and reduced water quality.

Conservation status

New South Wales, Biodiversity Conservation Act 2016: Vulnerable.

Victoria, Flora and Fauna Guarantee Act 1988: Vulnerable.

Breeding season

Timing varies between wetlands and years. The following pattern combines the documented breeding period, autumn dispersal and winter flocking behaviour. Local water levels and rainfall can shift when birds are present.

Survey timing should be adjusted to local water conditions. The species can be difficult to detect because it dives and may remain submerged ahead of approaching observers or aircraft.

  • Breeding: Breeding is reported from August to February, with spring and early summer breeding and nesting in dense wetland vegetation. Peak risk is generally September to January, but nests may persist into February.
  • Young: Ducklings remain with the female for about 4 to 5 weeks, and the documented breeding period means dependent young may occur from spring into late summer.
  • Movement and flocking: Young birds disperse in April and May from inland NSW breeding swamps to the Murray River system and coastal lakes. Non-breeding flocks commonly gather in autumn and winter on large deep open lakes and more saline wetlands.
  • Highest clearing risk: Clearing or disturbance is most likely to harm the species from August to February because nests, incubating females and dependent young may be present. January and February remain risk months even where breeding began earlier.

Identification

The Blue-billed Duck is a compact stiff-tailed diving duck that is usually seen on water rather than on land. It is shy and often dives when approached, so identification may require repeated observation from a distance.

Adult males in breeding plumage have a bright blue, broad scooped bill, glossy black head and upper neck, and rich chestnut to dark brown body plumage. The stiff pointed tail is normally held flat on the water, but may be held erect during courtship or when the bird is alarmed.

Females are brownish-black or brownish-grey, with narrow pale barring and mottling below. Non-breeding males, females and immature birds can look similar, and some males retain breeding plumage outside the breeding season.

Body length: 35 to 44 cm

Male breeding bill: Bright blue and broad, with a scooped or concave profile

Tail: Stiff, pointed feathers, usually flat on the water and erect during display or alarm

Identification: Similar species

The main field comparison is the Musk Duck, which is larger and has a more rounded head and a triangular bill. A Blue-billed Duck has a more concave bill and is noticeably smaller. Males are about 60 per cent shorter than male Musk Ducks, while females are about 30 per cent shorter, according to the cited field-guide comparison.

When the bill is dark or grey-green, use body size, head shape, bill profile, plumage barring and the stiff tail together rather than relying on bill colour alone.

Identification: Field signs and behaviour

The species is seldom seen on land. Birds commonly swim low in the water along the edge of dense cover, feed in open water or concealed bays, and dive when approached. Large non-breeding flocks may form on deep open lakes and dams, often well away from the shoreline.

Nests are bowl-shaped and usually placed in Cumbungi, also called bullrush or *Typha*, over deep water. Nests may also occur in trampled Lignum, sedges or spike-rushes. The species is usually quiet, although displaying males give rapid, low-pitched rattling sounds and females give a soft low quack.

  • Treat a diving duck that disappears ahead of an approaching boat, vehicle or aircraft as a possible Blue-billed Duck, particularly on deep water with dense aquatic vegetation.
  • Do not flush birds from suspected breeding vegetation unless necessary, because disturbance may affect nesting birds.

Distribution: National range

The Blue-billed Duck is endemic to Australia and occurs in temperate wetlands in the south-east and south-west. It is partly migratory or seasonally nomadic, with movements between inland breeding swamps, the Murray River system and coastal lakes.

The species occurs in New South Wales, Victoria, South Australia, Western Australia and Queensland, and has also been recorded in the Australian Capital Territory and southern Australian coastal waters. In eastern Australia it is widespread in New South Wales but is most common in the southern Murray-Darling Basin.

The supplied NSW distribution table records known or predicted occurrence across many NSW IBRA regions, including the Brigalow Belt South, Broken Hill Complex, Channel Country, Cobar Peneplain, Darling Riverine Plains, Mulga Lands, Nandewar, New England Tablelands, NSW North Coast, NSW South Western Slopes, Riverina, South Eastern Highlands and Sydney Basin.

Australian range: Temperate south-eastern and south-western Australia

States and territories identified in the supplied records: NSW, VIC, SA, WA, QLD and ACT

NSW strong regional association: Southern Murray-Darling Basin, especially Riverina and adjacent inland wetland regions

Distribution: Strongholds and subpopulations

In Victoria, important recorded areas include the Western Treatment Plant at Werribee, Devilbend Reservoir, western district lakes, north-west Victorian wetlands, Winton Wetlands, Newmerella Sewage Farm and Dowds Morass. The Western Treatment Plant has supported very large concentrations, particularly during drought years.

Other Victorian sites with records include Lake Wandella, Irymple Tank, Round Lake, Lake Elizabeth, Tutchewop and Pine Lake. The species has also been recorded at numerous dams, lakes, sewage treatment ponds, stormwater treatment wetlands and other artificial waterbodies.

Victorian waterbodies with records: 207 waterbodies in the cited Victorian analysis

Victorian breeding sites: 17 known sites in 2008 and 27 sites identified from later records to 2021

Recent high count: 811 birds at Pine Lake in March 2024

Important concentration site: Western Treatment Plant, Werribee, where more than 10,000 were recorded in 2013

Distribution: Population and trend

Population counts vary strongly with rainfall, water levels, salinity and the availability of suitable wetlands. Large artificial wetlands can hold a substantial proportion of the birds counted in Victoria, so counts from treatment ponds may not represent the condition of populations using natural wetlands.

North-west Victorian numbers declined between 1984 and 2008 in the cited analysis. More recent Victorian analysis indicates that counts can peak at 6,000 to 8,000 birds in some years, but are more commonly about 2,000 to 2,500 birds across Victoria.

Estimated Australian breeding population: About 12,000 breeding birds, estimate cited from 2000

Victorian long-term summer count average: 3,779 birds over 24 years, based on the cited 2013 report

Typical Victorian population range in later analysis: About 2,000 to 2,500 birds in most years

North-west Victoria maximum cited count: 374 at Lake Wandella on 14 March 1992

Habitat: Wetland types

Blue-billed Ducks require deep water, open flight space and dense aquatic or emergent vegetation. Habitat can occur in natural wetlands and in suitable artificial waterbodies, including treatment ponds and stormwater wetlands.

The species prefers deep water in large permanent wetlands and swamps with dense aquatic vegetation. It also uses deep open freshwater dams, lakes, reservoirs, sewage treatment ponds, settling ponds and other artificial wetlands. Water may range from fresh to saline, but suitable feeding and breeding conditions depend on water depth, vegetation and water quality.

The species is almost wholly aquatic and spends daylight hours either in concealed bays within vegetation or in exposed flocks on large open waterbodies.

Habitat: Structure and water conditions

Key features include at least 97 metres of open water for access and flight, with about 140 metres of deep open water identified as a breeding-habitat characteristic in the Victorian analysis. Dense Cumbungi, Ribbon Weed, Eel Grass, sedges, spike-rushes or Lignum provide cover and food resources.

Breeding habitat is associated with deep water, often more than 1 metre, and the Victorian habitat recommendations describe 1.5 to 2 metres or more as suitable for maintaining varied aquatic resources. European Carp can increase turbidity and damage benthic vegetation.

Minimum open-water distance observed: 97 metres

Open-water distance associated with breeding habitat: At least 140 metres

Recommended deep-water range in the cited Victorian guidance: About 1.5 to 2 metres, with some habitat extending to 5 metres

Waterbody use: Fresh to saline wetlands, with deep permanent water preferred

  • Retain deep open water beside dense emergent vegetation.
  • Avoid removing or simplifying Cumbungi, sedges, spike-rushes, Lignum and submerged vegetation around occupied wetlands.
  • Check for Blue-billed Ducks before works near deep permanent water, including artificial ponds and treatment wetlands.

Habitat: Climate and elevation

The species is associated with temperate wetlands in southern and eastern Australia and has no elevation limit reported in the supplied documents. It disperses more widely in dry years and may concentrate at reliable artificial wetlands when other wetlands become unsuitable.

Foraging habitat: Diet

Blue-billed Ducks feed in permanent water, often away from the shoreline. They dive to the bottom or feed at the surface, using open water near dense aquatic vegetation.

The diet includes aquatic insect larvae such as chironomid midges, caddisflies and dragonflies, as well as flies, water beetle larvae and other small aquatic invertebrates. Plant food includes seeds, buds, stems, leaves and fruit, with benthic and submerged vegetation supporting the invertebrate prey base.

The species feeds by diving and can remain submerged for up to 30 seconds. Feeding commonly occurs during the day, with early morning and late afternoon also reported as regular feeding times.

Main animal prey: Aquatic insect larvae, including chironomid, caddisfly, dragonfly, fly and water beetle larvae

Plant food: Seeds, buds, stems, leaves and fruit

Dive duration: Up to 30 seconds

Foraging water: Permanent, clear, deep water, often far from shore

Foraging habitat: Foraging habitat features

Foraging habitat includes the central parts of deep wetlands, open water beside dense cover, and areas with submerged or benthic vegetation such as Ribbon Weed and Eel Grass. These plants provide seeds and other plant material and support aquatic invertebrates.

European Carp can reduce foraging quality by increasing turbidity and damaging benthic vegetation. Salinity, drying, excessive vegetation growth and pollution can also reduce the suitability of a wetland.

  • Protect clear deep water and submerged vegetation from sediment, polluted runoff and excessive disturbance.
  • Manage European Carp where they damage benthic vegetation or increase turbidity.
  • Maintain a connection between open water and dense aquatic cover.

Breeding habitat: Breeding biology

Breeding is generally solitary and occurs in secluded, densely vegetated wetlands. Nests are placed over deep water or in low trampled wetland vegetation, with the female responsible for nest building and incubation.

The Blue-billed Duck is polygamous, with short-term pair bonds during copulation and egg laying. Males do not build the nest or incubate the eggs. Ducklings remain under the female's care for about 4 to 5 weeks.

Breeding dates vary between sources and sites. Records support breeding from August to February, with spring and early summer activity particularly important.

Breeding season: Usually August to February; one source gives August to November and another September to February

Clutch size: Usually 4 to 6 eggs, commonly 5 or 6

Incubation: 27 days

Time in nest or under early care: About 35 days in the nest; ducklings remain under the female for 4 to 5 weeks

Age at maturity: Not reported in the supplied documents

Lifespan: Not reported in the supplied documents

Breeding habitat: Nest habitat

Nests are usually constructed in Cumbungi or *Typha* beds over deep water. Other nesting sites include trampled vegetation in Lignum, sedges or spike-rushes. The nest is bowl-shaped, made mainly from dead *Typha* leaves and sometimes lightly lined with down.

Breeding wetlands need dense marginal vegetation close to deep open water. Open water allows birds to enter and leave the wetland, while dense cover provides concealment and protection from predators and disturbance.

  • Retain Cumbungi, sedge, spike-rush and Lignum stands beside deep open water.
  • Avoid clearing, slashing, burning or driving through nesting vegetation from August to February where birds or nests are present.
  • Use a qualified fauna spotter to inspect dense wetland vegetation before disturbance, and stop work if a nest or dependent young is found.

Sheltering habitat: Daytime cover

The species shelters on water rather than in terrestrial refuges. It uses dense aquatic vegetation and concealed wetland bays for daytime cover, nesting and protection from predators.

Non-breeding birds may spend daylight hours alone in small concealed bays within dense vegetation or in large exposed rafts well away from shore. Birds commonly swim low along the edge of cover and dive when approached.

There are no records in the supplied documents of tree hollows, burrows, dens, roost trees or terrestrial shelter structures used by this species.

  • Inspect concealed bays, reedbeds and dense marginal vegetation as well as open water during pre-clearance surveys.
  • Keep people, plant and boats away from occupied dense cover, especially during the breeding season.

Sheltering habitat: Nesting refuge

The nest is the main fixed shelter structure. It is a bowl-shaped nest in Cumbungi, Lignum, sedges or spike-rushes, generally over water or in low trampled vegetation. A nest may be difficult to see from the shoreline because the species selects secluded dense cover.

Nest location: Cumbungi or other dense wetland vegetation, generally over water

Nest form: Bowl-shaped structure made mainly from dead Typha leaves, sometimes lined with down

Known shelter dimensions: Not reported in the supplied documents

Threats: Clearing and construction

The main risks on development sites are loss or degradation of deep wetlands, disturbance of birds and nests, altered hydrology, poor water quality and removal of dense aquatic vegetation. Risk can extend beyond the work footprint where drainage, sediment or changed water levels affect the wetland.

Drainage, flood mitigation works, groundwater extraction, filling, wetland reclamation and clearing of Cumbungi or Lignum can remove breeding and foraging habitat. Clearing or slashing during the breeding season can destroy nests or cause abandonment.

Rubbish dumping, construction activity, vehicle access, recreation and close human approach can disturb birds. Blue-billed Ducks may leave otherwise suitable wetlands when disturbance is frequent.

  • Map deep open water, dense aquatic vegetation and wetland connections before finalising the work footprint.
  • Avoid clearing or slashing occupied wetland vegetation from August to February.
  • Use exclusion zones around occupied wetlands and suspected nests, and prevent vehicles from entering wet ground or reedbeds.
  • Control sediment, concrete washout, fuels, hydrocarbons and other pollutants so they do not enter wetland water.

Threats: Hydrology and water quality

Regulated river flows, water harvesting, groundwater decline, drainage, reduced lake levels, drought and altered flooding can reduce breeding and foraging habitat. Salinity increases can degrade dense wetland vegetation and reduce habitat quality.

European Carp can increase turbidity and damage submerged and benthic vegetation. Weeds can simplify breeding and foraging structure, while fire, frequent burning, grazing and overgrazing can reduce wetland vegetation.

  • Maintain natural or ecologically suitable wetting and drying patterns where the project controls water flows.
  • Prevent new drainage pathways and avoid lowering groundwater or wetland levels.
  • Keep pesticides and herbicides away from wetlands and manage saline or sediment-laden runoff.
  • Retain dense aquatic and emergent vegetation and prevent heavy grazing or repeated burning around occupied wetlands.

Threats: Predators, hunting and other pressures

Foxes, pigs and cats can prey on birds or affect nesting areas. Illegal hunting and accidental shooting are threats, and the species is protected and must not be hunted. Recreational boating and fishing can displace birds from previously suitable loafing habitat.

Aerial surveys may undercount Blue-billed Ducks because they dive and remain submerged ahead of approaching aircraft. Ground surveys should therefore include suitable concealed cover and account for the species' diving behaviour.

  • Manage foxes, pigs and cats around important breeding wetlands where authorised and practical.
  • Prevent dogs and people from entering breeding vegetation and use temporary wetland closures where needed.
  • Do not rely on a single aerial pass to rule out presence; combine distant observation with targeted ground checks by experienced observers.

Survey methodology: 1. Targeted wetland searches

Survey the Blue-billed Duck, Oxyura australis, as a waterbird of deep, permanent wetlands with open water and dense aquatic or emergent vegetation. The species is difficult to detect from the air because it can dive and remain submerged, so combine targeted ground observations with suitable waterbird counts and habitat assessment.

Search all deep permanent wetlands, dams, treatment ponds, lakes and densely vegetated swamps that could be affected by the project.

Prioritise sites with at least 97 metres of open water, and assess whether the site contains the larger open-water areas and dense marginal vegetation associated with breeding habitat.

Conduct searches from concealed positions at the wetland edge and from elevated points where available, scanning open water, sheltered bays and the edges of dense cover.

Search during daylight because the species feeds by day and may occur far from shore, either alone in concealed bays or in exposed flocks away from the shoreline.

Record birds that dive, noting that a bird may disappear before it can be identified or counted.

Typical body length: About 35 to 44 cm, with NSW guidance giving 40 cm.

Open-water detection feature: The species may dive and remain submerged when approached.

Useful habitat indicator: Deep water with dense aquatic or emergent vegetation, including Cumbungi or bullrush.

  • Repeat observations across suitable water levels and seasonal conditions where the project may affect an important wetland.
  • Record the number of birds, sex where possible, behaviour, plumage, location, water depth if known, open-water extent, aquatic vegetation and disturbance during each visit.
  • Treat a single absence survey cautiously where the wetland has dense cover, high turbidity, unsuitable water levels or recent disturbance.

Survey methodology: 2. Breeding and habitat searches

Survey dense Cumbungi, rush, sedge, Lignum and spike-rush margins for nests and broods during the breeding period.

The documented breeding period varies between sources, from August to November and from September to February, with Victorian guidance describing breeding from spring to late summer.

Do not enter breeding vegetation or flush birds unless this is necessary and authorised, because disturbance can cause nest abandonment.

Typical clutch size: Four to six eggs in the Australian Museum account, and most commonly five or six in NSW guidance.

Incubation: About 27 days.

Time in nest: About 35 days.

Young dispersal: NSW guidance records dispersal in April and May from inland breeding swamps to non-breeding areas.

  • Look for solitary nests over deep water, constructed in Cumbungi or other low, trampled wetland vegetation.
  • Record females, ducklings, recently fledged birds, territorial or courtship behaviour, nests and repeated use of the same wetland.
  • Map breeding habitat separately from loafing habitat, because large treatment ponds may support many birds without supporting breeding.
  • Use the presence of dense fringing vegetation, clear open water and benthic or aquatic vegetation as habitat indicators, not as proof that birds are present.

Survey methodology: 3. Waterbird counts and aerial survey limits

Use established ground-based waterbird count methods where the project affects a wetland used by many waterbirds, and include the Blue-billed Duck in the count sheet.

Aerial surveys can cover large or inaccessible wetlands, but they are not sufficient as the only method for this species.

Aerial observers may miss diving Blue-billed Ducks, particularly when aircraft approach, and aerial counts can be underestimated by at least a factor of two in some conditions.

Aerial survey limitation: Blue-billed Ducks may dive and remain submerged ahead of an approaching aircraft.

Dense-cover limitation: Ground counters may miss birds in the middle of large wetlands, while aerial surveys may miss birds in dense cover.

  • Use aerial survey results to identify wetlands or habitat areas requiring targeted ground inspection, rather than to demonstrate absence.
  • Record survey date, start and finish time, observer numbers, route or search area, weather, visibility, water conditions, survey platform and detection limitations.
  • Do not compare counts from different methods or conditions without documenting the likely effect of detectability.

Survey methodology: Minimum effort and reporting

  • Define the survey area to include the impact footprint, connected wetlands, access routes, proposed spoil or drainage areas and any downstream wetland that could receive altered flows.
  • Visit in suitable weather and visibility, and repeat the survey when water levels, flooding, salinity or seasonal movement could change the result.
  • Use targeted searches for identified wetland resources and document the search duration, observers, method, conditions, area covered and all detections and non-detections.
  • Have a qualified ecologist assess whether additional surveys are needed where the wetland contains deep open water, dense Cumbungi, breeding evidence, large flocks or a history of records.
  • Submit verified records and nil records, where requested, to the relevant state database, including the NSW BioNet Atlas and the Victorian Biodiversity Atlas.
  • Retain photographs, coordinates, count sheets, habitat maps, field notes and any evidence supporting the identification.

Before habitat disturbance: Avoid and minimise habitat loss

Plan the work around the wetland functions the species uses: deep open water, dense aquatic vegetation, secure nesting cover and low disturbance. Avoid removing or isolating suitable wetlands where practicable.

Retain deep permanent water, open-water flight paths, dense Cumbungi and other emergent vegetation, aquatic vegetation and connected wetland margins.

Give highest protection to wetlands with breeding records, repeated use, ducklings, nests, flocks or suitable breeding structure.

Avoid drainage, filling, dewatering, salinity increases, altered inflows and works that reduce water depth or cause rapid loss of wetland vegetation.

Maintain movement between breeding swamps, wintering lakes and other retained wetlands where the project affects more than one wetland.

Open-water habitat observation: A minimum open-water distance of 97 metres has been observed at waterbodies used by the species.

Breeding habitat observation: Victorian guidance identifies at least 140 metres of deep, open water, visible aquatic vegetation and Cumbungi bordering deep water as common breeding features.

  • Locate access tracks, compounds, laydown areas, stockpiles and sediment controls outside retained wetland habitat.
  • Set site-specific no-go areas and disturbance buffers around occupied wetlands, nests, broods and dense nesting vegetation, based on advice from the project ecologist and relevant regulator.
  • Prevent machinery, people, dogs and recreational activity from approaching occupied birds or nesting vegetation.
  • Use a wetland-sensitive drainage and erosion plan to prevent sediment, nutrients, pesticides, herbicides, concrete washout and other pollutants entering the water.

Before habitat disturbance: Approvals and work planning

The species is not listed under the EPBC Act in the supplied records, but it is listed as Vulnerable in New South Wales and Victoria.

Confirm the current state listing, local wildlife legislation, wetland approvals, waterway approvals and any permit requirements before works begin.

Obtain project-specific advice on whether the action may affect another EPBC listed matter or a Ramsar wetland, even though this species is not nationally listed.

NSW status: Vulnerable.

Victoria status: Vulnerable and listed under the Flora and Fauna Guarantee framework.

Commonwealth status: Not listed in the supplied NSW profile and project records.

  • Prepare a fauna management plan that identifies survey results, habitat to be retained, wetland protection controls, fauna handling arrangements, stop-work triggers and reporting responsibilities.
  • Schedule vegetation removal, dewatering and noisy works outside the local breeding period where practicable, noting that breeding timing varies between August and February in the supplied sources.
  • Stage works so that retained wetland habitat remains available and birds are not forced into unsuitable or unsafe waterbodies.
  • Confirm the ecologist, fauna spotter catcher, wildlife carer and veterinary contacts before mobilisation.

Before habitat disturbance: Pre-clearance preparation

  • Complete a pre-clearance inspection of all wetlands, wetland vegetation, drainage lines, dams and connected habitat within and beside the disturbance area.
  • Mark retained open water, Cumbungi, rushes, sedges, Lignum, aquatic vegetation, access exclusions and sediment controls before machinery enters the site.
  • Check dense wetland vegetation carefully for nests, females with young and birds sheltering close to the shoreline.
  • Fence or otherwise exclude machinery from retained wetland habitat where this can be done without blocking bird movement or causing birds to congregate in unsafe areas.
  • Use a qualified ecologist to approve any dewatering, vegetation removal or wetland isolation after the pre-clearance inspection.

During habitat disturbance: Daily controls and machine coordination

Keep wetland impacts under daily ecological control. The fauna spotter catcher should work with the machine operator and supervisor, not after the habitat has already been disturbed.

Inspect exclusion fencing, wetland controls, sediment controls and retained vegetation before work starts each day.

The fauna spotter catcher must brief operators on the approved work limits, approach direction, exclusion areas and stop-work procedure.

Use slow, staged clearing towards retained habitat only where the ecologist has confirmed that this will not drive birds into active machinery, roads or unsafe water.

Keep plant, workers, vehicles, dogs and lighting away from occupied wetland margins and nesting vegetation.

  • Stop work if a Blue-billed Duck is found within the active work area, if a nest or brood is found, if birds cannot move safely away, or if controls fail and sediment or pollution enters the wetland.
  • Do not chase, corner, net or flush a diving duck to improve identification.
  • Do not start or resume work until the fauna spotter catcher and project ecologist have assessed the animal, habitat and work method.
  • Record the location, time, work activity, people involved, animal behaviour, controls applied and the decision to resume or modify work.

During habitat disturbance: Handling and relocation

Treat the Blue-billed Duck as a specialist aquatic bird that may dive when approached, rather than attempting repeated capture from the water.

Only an appropriately authorised and experienced person should handle the bird, and handling should be limited to what is required for immediate safety, veterinary care or lawful relocation.

If relocation is approved, use nearby retained wetland habitat that has suitable deep open water, cover and low disturbance, with the location selected by the ecologist and relevant authority.

Preferred refuge habitat: Deep water in a large permanent wetland or swamp with dense aquatic vegetation.

Feeding position: Birds may feed far from shore and dive to the wetland bottom.

  • Do not relocate a bird away from its wetland without ecological and regulatory advice, particularly during breeding.
  • Keep the bird quiet, cool and secure during any authorised transport, and follow the approved fauna handling procedure.
  • Send an injured or exhausted bird to a veterinarian or licensed wildlife carer as soon as practicable.
  • Do not release a bird into a shallow, saline, polluted or heavily disturbed waterbody.

During habitat disturbance: Wetland and habitat feature protection

  • Do not remove Cumbungi, rushes, sedges or Lignum that may contain nests unless the ecologist has confirmed that removal is authorised and no practical avoidance option remains.
  • Do not lower, drain or isolate water without a staged dewatering plan that addresses birds, nests, fish, frogs, water quality and downstream flows.
  • Keep spoil, sediment, fuel, concrete washout, herbicides and pesticides away from open water and wetland vegetation.
  • Control European Carp and other processes that damage benthic vegetation where this is part of the approved project or rehabilitation plan.
  • Do not apply hollow-bearing tree, log, rock or burrow procedures to this species as a substitute for wetland assessment, because the Blue-billed Duck uses aquatic and emergent wetland habitat.

After habitat disturbance: Post-clearance inspection

Confirm that the work has not removed occupied habitat, altered wetland condition or caused birds to abandon a site. Keep wetland controls in place until the risk of indirect impact has ended.

Inspect the work area and retained wetland immediately after clearing, dewatering, demolition or other disturbance.

Check for stranded, injured or displaced birds, damaged nests, loss of open water, damaged Cumbungi, sediment deposition, turbidity, pollution and changed drainage.

Repeat targeted searches where the pre-clearance survey recorded Blue-billed Ducks, breeding evidence, large flocks or suitable habitat.

  • Use the same mapped observation points where practicable so that changes in bird use and habitat can be compared.
  • Record bird numbers, behaviour, habitat condition, water level, open-water extent, vegetation condition and any corrective action.
  • Report injured animals, deaths, nest damage, unapproved habitat loss and pollution incidents under the project approval and state requirements.

After habitat disturbance: Monitoring and controls

  • Maintain exclusion fencing, sediment controls, spill controls and access restrictions until the ecologist confirms that the wetland is stable and the works no longer pose a direct or indirect risk.
  • Monitor retained and rehabilitated wetlands through the relevant breeding and non-breeding periods where the project changes water levels, vegetation, access or disturbance.
  • Compare monitoring results with the pre-work baseline, including presence, counts, breeding evidence, water depth, salinity where relevant, aquatic vegetation and open-water area.
  • Escalate declining use, repeated disturbance, drying, increasing salinity, weed spread or loss of nesting vegetation to the project manager and regulator.

After habitat disturbance: Reporting and offsets

  • Complete a close-out report with maps, survey effort, records, handling events, injuries, deaths, habitat loss, rehabilitation actions, monitoring results and unresolved risks.
  • Submit verified records to the relevant state wildlife database, including NSW BioNet or the Victorian Biodiversity Atlas where applicable.
  • Obtain regulator advice on offsets, compensatory habitat or formal restoration requirements if approved works cause unavoidable loss or degradation of listed state habitat.
  • Do not describe an offset as replacing a retained breeding wetland unless the relevant approval explicitly accepts that approach.

Rehabilitation actions: Wetland design and planting

Rehabilitation should recreate a deep, permanent or reliably inundated wetland with clear open water, productive aquatic vegetation and secure emergent nesting cover. Design the site for both breeding habitat and non-breeding flock use.

Reinstate deep open water with an unobstructed approach and departure area, while retaining dense vegetation at selected margins for shelter and nesting.

Plant or encourage locally appropriate native aquatic and emergent vegetation, including Cumbungi where suitable, together with aquatic and benthic plants that support invertebrates and plant foods.

Use local wetland reference sites and the project ecologist's design to set water depth, inundation pattern, salinity limits and vegetation zones.

Documented breeding design feature: At least 140 metres of deep, open water, with aquatic vegetation and Cumbungi bordering the open water.

Documented general use feature: At least 97 metres of open water has been observed at waterbodies used by the species.

Water depth guidance: Victorian habitat recommendations describe deep water from 1.5 to 2 metres, with some areas up to 5 metres.

  • Design the wetland with at least 140 metres of deep open water where the objective is to recreate documented Blue-billed Duck breeding habitat.
  • Maintain at least 97 metres of open water at sites intended to provide general habitat, recognising that this is an observed minimum rather than a universal design standard.
  • Avoid rapid drying, shallow basins that become overgrown and steep vegetation barriers that reduce safe access to open water.
  • Keep breeding areas protected from recreational boating, fishing, dogs and close human approach.

Rehabilitation actions: Water, weeds and predators

Salinity management reference: The supplied Victorian guidance identifies about 5,000 mg/L as a salinity level not to exceed where practicable.

Threats identified in NSW: Drainage, flood mitigation, groundwater extraction, flow regulation, water harvesting, salinity, grazing, pollutants, weeds, predators and disturbance.

  • Maintain ecologically sustainable inflows and allow flooding and recession to occur as naturally as the project permits.
  • Prevent salinity increases and monitor salinity where groundwater, irrigation return flows, drought or drainage changes could affect the wetland.
  • Control European Carp where they cloud the water and damage benthic vegetation, and control weeds that simplify breeding or foraging habitat.
  • Manage foxes, pigs, cats and other predators around breeding wetlands in accordance with the approved fauna and pest management plans.
  • Exclude heavy or prolonged grazing from Cumbungi and Lignum nesting areas.

Rehabilitation actions: Monitoring and success measures

Victorian breeding records: The supplied profile identifies 27 Victorian sites where breeding has occurred.

Victorian population context: The profile reports that the population in Victoria commonly ranges from about 2,000 to 2,500 birds, with occasional peaks of 6,000 to 8,000.

  • Monitor water level, water depth, open-water distance, salinity where relevant, aquatic vegetation, Cumbungi condition, weed cover, carp presence and human disturbance.
  • Survey for Blue-billed Ducks during both the breeding period and the non-breeding period, using the same observation points and methods as the baseline survey.
  • Measure success by sustained suitable water, retained open-water access, established aquatic and emergent vegetation, absence of major pollution or carp impacts, and repeated use by Blue-billed Ducks.
  • Record breeding evidence separately from flock counts because a wetland may support large loafing flocks without supporting recruitment.
  • Continue monitoring until the ecologist and approval authority agree that the wetland is functioning and management actions can be reduced.

Sources