Species profile—Botaurus poiciloptilus (Australasian bittern)

Classification

Animalia (animals) → Aves (birds) → Ardeidae (herons, egrets and bitterns) → Botaurus poiciloptilus (Australasian bittern)

Sighting data

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Species details

Kingdom

Animalia (animals)

Class

Aves (birds)

Family

Ardeidae (herons, egrets and bitterns)

Scientific name

Botaurus poiciloptilus (Wagler, 1827)

Common name

Australasian bittern

WildNet taxon ID

1836

Alternate name(s)

brown bittern
Australian bittern

Nature Conservation Act 1992 (NCA) status

Endangered

Environment Protection and Biodiversity Conservation Act 1999 (EPBC) status

Endangered

Conservation significant

Yes

Wetland status

Wetland Indicator Species

Endemicity

Native

Pest status

Nil

Description

This species is a large, powerfully built bird. The adult is rufous, streaked and mottled dark brown and buff above. They have a pale eyebrow and throat, separated by dark brown streaking to the side of the face and neck. The breast is paler and streaked brown, buff and rufous. The bill is yellowish and the bare facial skin (between the bill and eye) is olive to blue-grey. The long, heavily built legs are olive-green to dull yellow in colour. Juveniles are paler with much buff flecking on the back. The Australasian bittern grows to 65-75cm tall. (Pizzey & Knight 1997; Van Tets 1988; Marchant & Higgins 1990; Morcombe 2000).

Map

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Distribution

The species is found throughout New South Wales, Victoria and Tasmania to southern Queensland and eastern South Australia, also the south-west corner of Western Australia. It also occurs in New Zealand and New Caledonia. Population contains about 2500 mature individuals. (Marchant & Higgins 1990; Pizzey & Knight 1997; Garnett & Crowley 2000).

Distributional limits

-23, 144.2
-29.2, 153.55

Range derivation

Range derived from extent of the taxon's confirmed records

Species environment

Aquatic & Terrestrial

Habitat

The Australasian bittern inhabits shallow (less than 30cm deep), permanent freshwater and brackish swamps or lagoons that are densely vegetated (e.g. tall reeds, sedges, lignum). They also inhabit bore drains with tussocky vegetation and occasionally saltmarsh. They use temporary pools when population densities are high and deep swamps when breeding. (Storr 1984; Pringle 1985; Marchant & Higgins 1990; Garnett 1992a; Pizzey & Knight 1997).

Burrows and nests

The shallow saucer-shaped nest is a rough platform of sticks and reeds, constructed in a dense reed clump or tall dense swamp vegetation, up to 1m above the water level. (Beruldsen 1980; Van Tets 1988).

Behaviour

The species live solitary, in pairs and sometimes loose groups of up to twelve. The Australasian bittern is cryptic (secretive), crepuscular (active at dawn and dusk) and nocturnal (active at night) and occasionally diurnal (active by day), roosting in reedbeds when inactive. It is sedentary (remaining in one area) with local movements and occasional population irruptions as they take advantage of ephemeral (temporary) wetlands. They establish feeding and breeding territories within loose colonies, territories contain a mixture of tall and short sedges. When initially taking flight, the neck is outstretched, the legs dangle and the wings are broad. On longer flights it holds its neck hunched back, the feet trail behind the tip of the tail and they use slow, steady, shallow wing beats. (Blakers et al. 1984; Van Tets 1988; Marchant & Higgins 1990; Garnett 1992b; Pizzey & Knight 1997; Garnett & Crowley 2000).

Reproduction

Breeding takes place from September-January or during flood. They lay 3-6 pale olive, green-brown eggs per clutch (usually 4-5), incubating them for 25 days. Fledging takes place at 4 weeks. (Beruldsen 1980; Van Tets 1988).

Diet

The Australasian bittern feeds in dense cover over water, taking crustaceans (e.g. crayfish), fish (e.g. eels) and frogs, also insects, reptiles, small mammals (mice) and birds. They typically forage in shallow water up to 0.3m deep. (Pringle 1985; Van Tets 1988; Marchant & Higgins 1990).

Threatening processes

Known : 1. Destruction of habitat through drainage of wetlands for agriculture, salinisation of swamps following clearance of catchments, and over-grazing of swamp vegetation by domestic stock (drought refuges likely to be most vulnerable habitats) (Garnett 1992a; Garnett & Crowley 2000).
Suspected : 1. Habitat degradation due to fire (Garnett 1992b).

Status notes

Priority taxon in Brigalow Belt South and South-east Queensland bioregion (McFarland et al. 1998; SEQ Expert Panel 2007); considered Vulnerable (Garnett & Crowley 2000). DELETED FROM BBS LIST.

Notes

Contributors: David McFarland 26/10/2007; Mellisa Mayhew 16/10/2008; Wayne Martin 09/11/2008

References

Beruldsen, G. (1980). A Field Guide to Nests and Eggs of Australian Birds. Rigby, Adelaide.
Blakers, M., Davies, S.J.J.F. & Reilly, P.N. (1984). The Atlas of Australian Birds. RAOU & Melbourne University Press, Melbourne.
Garnett, S. (1992a). The Action Plan for Australian Birds. Australian Nature Conservation Agency, Canberra.
Garnett, S. (1992b). Threatened and Extinct Birds of Australia. RAOU Report No. 82; RAOU & ANPWS, Melbourne.
Garnett, S.T. & Crowley, G.M. (2000). The Action Plan for Australian Birds 2000. Birds Australia & Environment Australia, Canberra.
Marchant, S. & Higgins, P.J. (Eds) (1990). Handbook of Australian, New Zealand & Antarctic Birds, Vol. 1, Ratites to Ducks, Part B, Pelican to Ducks. Oxford University Press, Melbourne.
McFarland, D., Haseler, M. & Venz, M. (1998). Brigalow Belt South Bioregion: Preliminary Listing Of Priority And Secondary Assessment Fauna. Forest Assessment Unit, Queensland Department Of Environment & Heritage.
McFarland, D.C. (2007). Taxon Profiles Version 2.0: Threatened And Priority Fauna Taxa In Queensland: Biology And Distribution. Queensland Environmental Protection Agency, Brisbane.
Morcombe, M. (2000). Field Guide to Australian Birds. Steve Parish Publishing Pty Ltd, Archerfield.
Pizzey, G. & Knight, F. (1997). The Field Guide to the Birds of Australia. Angus & Robertson, Sydney.
Pringle, J.D. (1985). The Waterbirds of Australia. Angus & Robertson, Sydney.
SEQ Expert Panel (2007). Biodiversity Planning Assessment Southeast Queensland Expert Fauna Panel Report. Environmental Protection Agency, Brisbane.
Storr, G.M. (1973). List of Queensland Birds. Special Publication of Western Australian Museum. No. 5, 1-177.
Storr, G.M. (1984). Revised List of Queensland Birds. Rec. West. Aust. Mus. Suppl. No. 19, 1-189.
Van Tets, G.F. (1988). Australasian Bittern Botaurus poiciloptilus (Wagler, 1827). In : Reader's Digest Complete Book of Australian Birds. (Eds Schodde, R. & Tidemann, .C.), pp. 107. Reader's Digest, Sydney.

Profile author

David McFarland (09/11/2008)

Other resources

• Species Profile and Threats Database (SPRAT)
• Online Zoological Collections of Australian Museums (OZCAM)
• Atlas of Living Australia

Data source

This profile data is sourced from the QLD Wildlife Data API using the Get species by ID function used under CC-By 4.0.
https://apps.des.qld.gov.au/species/?op=getspeciesbyid&taxonid=1836.

This information is sourced from the WildNet database managed by the Queensland Department of Environment and Science.