Tuesday 18 June
Australasian bittern (Botaurus poiciloptilus)
- The Australasian bittern is well camouflaged, and if disturbed will freeze and assume an erect posture with the bill pointed skywards.
- The booming call of the Australasian bittern can be heard up to a kilometre away.
- The eerie call of the Australasian bittern has been suggested as the origin of the myth of the ‘bunyip’, a creature which was said to live in swamps, billabongs and waterholes.
- The Australasian bittern has been seen using grass to bait fish, luring the fish in so it can catch them.
Australasian bittern fact file
- Find out more
- Print factsheet
Australasian bittern description
The Australasian bittern (Botaurus poiciloptilus) is a large and stocky waterbird with a thick neck and camouflaged plumage (2). The upperparts of the Australasian bittern are dark brown to black, with mottled buff patterns to aid in camouflage. Its underside is pale yellow to buff with streaks of brown, while its chin and throat are pale (2) (3) (4). This species has a thick, black stripe on the side of the neck and a pale stripe above the eye (2) (3).
The Australasian bittern has a buff-coloured bill which is straight and pointed. Its legs and feet are pale green to olive, and its eyes are orange-brown to yellow (2) (3) (5).All bitterns have long legs and toes which are useful for wading in swamps and wetlands (6).
Variation in the colouration of the Australasian bittern has been observed, with individuals showing darker or paler plumage, but this is not well understood (2). The male and female Australasian bittern are similar in appearance, but the female is smaller than the male (2) (5). Juveniles are similar in appearance to the adult, but are paler and have a rufous-streaked underside and heavy buff flecking on the back (3) (5).
- Also known as
- Australian bittern, black-backed bittern, boomer, brown bittern, bull-bird, bullhead, bunyip bird.
- Ardea poiciloptila.
- Length: 66 - 76 cm (2) (3)
- Wingspan: 105 - 118 cm (2)
- Male weight: 875 - 2,085 g (3)
- Female weight: 571 - 1,135 g (3)
Birdlife International - Australasian bittern:
BirdLife Australia - Bittern project:
IUCN SSC Heron Specialist Group - Australasian bittern:
- To keep eggs warm so that development is possible.
IUCN Red List (November, 2012)
Department of Sustainability, Environment, Water, Population and Communities (2012) Botaurus poiciloptilus. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
IUCN SSC Heron Specialist Group - Australasian bittern (November, 2012)
NSW National Parks and Wildlife Service (1999) Threatened Species Information: Australasian Bittern. NSW National Parks and Wildlife Service, Hurstville, New South Wales. Available at:
- McKilligan, N. (2005) Herons, Egrets and Bitterns: Their Biology and Conservation in Australia. CSIRO Publishing, Collingwood, Australia.
RSPB - Bitterns and herons (November, 2012)
Birdlife International - Australasian bittern (November, 2012)
BirdLife Australia - Bittern project (November, 2012)
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
Australasian bittern biology
The Australasian bittern usually hunts at dawn and dusk (2), or sometimes at night, and predates fish, frogs, crayfish and aquatic insects (7). It has also been recorded feeding on lizards, birds, rats, mice, leaves and fruit (2) (3) (5). When hunting, the Australasian bittern may keep still for minutes at a time before lunging at its prey, or it may keep its head and neck parallel to the water’s surface and sway its head from side to side. The Australasian bittern may eat its prey whole or shake or beat it to subdue it. This species has also been observed using grass to bait fish (2) (3) (5).
The Australasian bittern is a solitary bird that is often heard but not seen due to its effective camouflage. When disturbed, the Australasian bittern stays completely still and will blend into the vegetation by compressing its plumage and pointing its bill upwards. Alternatively, it may lower itself down gently into the reeds and rushes (2).
The mating call of the Australasian bittern can be heard in spring and early summer (8). Males will emit very deep 'booms' in a series which can last about 10 to 15 seconds, and these calls can be heard up to a kilometre away (2).
The Australasian bittern breeds in single pairs, from October to February in Australia and from September to November in New Zealand (2). This bittern nests in vegetation stands in swamps, and usually builds its nest about 30 centimetres above the water level, with the nest itself consisting of a platform of reeds, rushes and grass. Generally four or five eggs are laid per clutch. The female Australasian bittern incubates the eggs for about 25 days and, once the eggs have hatched, the female alone feeds the juveniles until they are about 7 weeks old, when they fledge (2) (3).Top
Australasian bittern rangeTop
Australasian bittern habitatTop
Australasian bittern status
The Australasian bittern is classified as Endangered (EN) on the IUCN Red List (1).Top
Australasian bittern threats
The Australasian bittern has a small and rapidly declining population, mainly due to the loss and destruction of its natural habitat (7). Its very specific habitat requirements means the Australasian bittern is very sensitive to loss of wetlands as areas have been drained for irrigation or to convert land to agriculture (2) (7).
The salinisation (increasing saltiness) of its habitat is also a threat to the Australasian bittern, and high levels of grazing together with altered fire regimes are also further degrading the wetlands it relies on. In addition, the eggs of the Australasian bittern may be predated by introduced species such as foxes and cats, and the adult birds have been known to desert their nest if disturbed by humans (2) (4) (7).Top
Australasian bittern conservation
In Australia, there are already several sites dedicated to the management of the Australasian bittern population, such as Bool Lagoon and Lake Muir (7). In 2007, a Bittern Project was set up which aims to study the Australasian bittern and its habitats, raise awareness, and educate the local community in an attempt to limit habitat destruction (7) (8). In Australia, the Australasian bittern is protected under the Environment Protection and Biodiversity Conservation Act (2).
Future conservation actions proposed for the Australasian bittern include surveys to determine accurate population estimates, as well as identifying and protecting this species’ habitats (2) (7). It will also be important to rehabilitate former breeding habitat and involve community groups to help collect information and conserve this waterbird (2) (4).Top
Find out more
Find out more about the Australasian bittern and its conservation:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
More »Related species
Play the Team WILD game
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.