Download Australasian Bittern

THREATENED SPECIES INFORMATION
Australasian Bittern
Botaurus poiciloptilus (Wagler, 1827)
Other common names Boomer, Bullhead, Blue-backed or Brown Bittern
Conservation status
The Australasian Bittern is listed as a
Vulnerable Species on Schedule 2 of the
Threatened Species Conservation Act, 1995
(TSC Act).
Description (summarised from Schodde &
Tidemann 1986; Marchant & Higgins 1990)
Head and Body Length
650-750mm
Wingspan
1050-1180mm
Wing
309-378mm
Tail
102-135mm
Bill
63-75mm
Tarsus
89-112mm
Weight
900-1400g
The Australasian Bittern is large and stocky
heron with mottled dark brown, light brown
and buff plumage. The chin and throat are
white and underparts are pale yellow to buff
with brown streaks.
Males, females and juveniles are all similar,
although the female is smaller than the male
and the juvenile is paler in colour.
The species has a characteristic booming
call that is mainly heard at dawn and dusk
during the breeding season (spring and
summer). When disturbed this species will
flush and then drop rapidly into dense
vegetation.
NPWS
Australasian Bittern
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LEGEND
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Australasian Bittern
pre 1980 sightings
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Austral asian Bittern
post 1980 sightings
Austral asian Bittern
pr edicted distribution
Roads
Rivers
Map Compiled From:
Species Sightings from the NPWS Atlas of NSW Wil dlife Database
Pr edicted distribution data from Ayers et al. 1996
Roads and Riv ers data from AUSLIG
Copyright NSW National Parks and Wildlife Service, Sep tember 1999
This map is not guaranteed to be fr ee from err or or omission
The NSW National Par ks and Wil dlife Serv ice and its employees
discl aim l iabil ity for any act done or omission made on the
inform ation in the m ap and any consequences of such acts or omissions
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0
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100 Kilometer s
NPWS records of the Australasian Bittern in NSW
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Distribution
The Australasian Bittern occurs from
southern Queensland to Tasmania and south
eastern South Australia, including most of
NSW and Victoria (Marchant & Higgins
1990). It also occurs in the south-western
corner of Western Australia, although these
populations have declined in numbers and
range (Smith et al. 1995).
In NSW, the species has been observed along
the coast as well as in wetlands of the
Murrumbidgee and Lachlan Rivers and is
frequently recorded in the Murray-Darling
Basin (Marchant & Higgins 1990; NPWS
1999).
Recorded occurrences in
conservation reserves
Morrisons Lake NR, Cecil Hoskins NR,
Guy Fawkes River NP, Maquarie Marshes
NR, Eurobodalla NP, Montague Island NR,
Seven Mile Beach NP, Killalea SRA,
Dharug NP, Willandra NP, Hexham Swamp
NR, Kooragang NR, Gibraltar Range NP,
Lake Innes NR, Bundjalung NP, Kinchega
NP, Bournda NP (NPWS 1999).
Habitat
The Australasian Bittern inhabits terrestrial
and estuarine wetlands, generally where
there is permanent water. The species
prefers wetlands with dense vegetation,
including sedges, rushes and reeds.
(Marchant & Higgins 1990; Garnett 1992).
THREATENED SPECIES INFORMATION
Freshwater is generally preferred, although
dense saltmarsh vegetation in estuaries and
flooded grasslands are also used by the
species (Smith et al. 1995).
Ecology
The Australasian Bittern is a shy and cryptic
bird. During the day, it roosts on the ground
amongst dense reeds, rather than in trees
(Marchant & Higgins 1990). The species
builds a foraging platform by trampling
reeds and sedges. At dusk, the species
forages in shallow water up to 30cm deep,
primarily feeding on frogs, fish,
invertebrates (including crayfish), leaves and
fruit (Barker & Vestjens 1989).
The species can be seen singly, in pairs or
in groups of up to 12 individuals (Marchant
& Higgins 1990). Although generally
sedentary, the species often moves in
response to flooding and drought (Smith et
al. 1995).
The nest is constructed of trampled reeds
and rushes and is generally located amongst
dense vegetation over shallow water. The
clutch size is thought to be between 4 and 5
eggs. (Marchant & Higgins 1990)
Threats (summarised from Smith et al. 1995;
Garnett 1992)
• Grazing and trampling of riparian
vegetation and siltation of waterbodies
by livestock
• Predation by foxes on eggs and juveniles
• Alteration of flooding regimes as a result
of the regulation of waterways,
particularly inland, thus reducing the
suitability and availability of wetlands
• Clearing of riparian vegetation and
drainage of habitat for agriculture and
peat mining
• Drainage, salinisation, siltation and
pollution of wetlands and waterbodies
• Degradation of drought refuges
• Poor representation of preferred habitats
in conservation reserves
Management
• Further research to establish the numbers
of birds in NSW, their habitat and
drought refuge requirements, diet and
predators, breeding range and
movements
• Involvement of community groups and
bird associations in gathering
information
• Protection and management of habitat,
including fencing of riparian vegetation
to prevent trampling and grazing by
cattle
• Control of feral animals, in particular
foxes and cats
• Development of appropriate guidelines
for wetland management
Recovery plans
A recovery plan has not been prepared for
the Australasian Bittern.
References
Ayers D., Nash S. and Baggett K. 1996 Threatened Species of Western NSW. NSW NPWS, Hurstville
Barker R.D. and Vestjens W.J.M. 1989. The Food of Australian Birds: Volume 1 Non-Passerines.
CSIRO, Melbourne.
Garnett S. 1992. Threatened and Extinct Birds of Australia. Royal Australian Ornithologists Union
and Australian National Parks and Wildlife Service, Canberra.
Marchant S. and Higgins P.J. (Eds) 1990. Handbook of Australian, New Zealand and Antarctic
Birds. Volume 1 Ratites to Ducks: Part B Australian Pelican to Ducks. Oxford University Press,
Melbourne.
NPWS 1999. Atlas of NSW Wildlife. NPWS, Hurstville.
Schodde R. and Tidemann S.C. 1986. Reader’s Digest Complete Book of Australian Birds. Reader’s
Digest Services Pty Ltd, Surrey Hills.
Smith P.J., Smith J.E., Pressey R.L. and Whish G.L. 1995. Birds of Particular Conservation Concern
in the Western Division of New South Wales: Distribution, Habitats and Threats. NSW NPWS,
Hurstville.
For further information contact
Threatened Species Unit, Policy and Science Directorate Phone 02 9585 6540.
General enquiries: 43 Bridge St Hurstville NSW 2220 Phone 1300 36 1967 or 02 9585 6333.
Web site www.npws.nsw.gov.au
© September 1999.
Important Disclaimer
While every effort has been made to ensure the accuracy of the information in this publication, the NSW National Parks and
Wildlife Service disclaims any responsibility or liability in relation to anything done or not done by anyone in reliance upon the
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