Have you seen an Australasian bittern lately? If your answer was ‘no’ (and it almost certainly was), it is hardly surprising—they are one of The bunyip bird – the most difficult to spot birds in the country. If you’re lucky, you may have heard one. The birds’ booming call, Australia’s newest emanating deep from within misty swamps and billabongs, is the most likely source of the bunyip legend in Aboriginal folklore—a legend endangered species which haunted early white settlers unfamiliar with the sounds of the Australian bush. The ‘bunyip bird’ also goes by several other noms de plume, including ‘boomer’ and ‘Murray bull’; all due to the nature of its Andrew Silcocks & John Peter extraordinary calls, which have been likened to the lowing of cattle. Birdlife Australia Yet it is incredibly challenging to see the Australasian bittern in the This text of this article is an edited version of an article written for the Wingspan Magazine, published by Birdlife Australia (previously known wild. Their cryptic plumage and posture, their shy nature and habitat as Birds Australia) of impenetrable reeds and rushes, as well as their probable population decline as a result of drought and the loss and degradation of their wetland habitats, all contribute to their ‘tough-to-twitch’ nature. It is hardly surprising, then, that the Australasian bittern is one of our QUICK TAKE least-known and least-studied species. Because bitterns are so difficult to find they are also difficult to study, and so the plight of the species ›› The Australasian bittern is a shy bird that inhabits wetlands has slipped under the radar.

with dense reeds and rushes. The bird has a booming call A wetland to call home that combined with its infrequent sighting most likely led to The Australasian bittern is restricted to moist, temperate regions of Australia and New Zealand. In Australia, they occur on the east legends about bunyips. coast from Bundaberg in Queensland’s south to Tasmania and west to Adelaide. There is another small population in the south- western corner of Western Australia. While this range appears to be ›› Drought and loss of habitat have led to the Australasian bittern widespread, this is deceptive, as the number of wetlands within this being listed as an endangered species. area that are suitable for habitation by bitterns is declining. The problem is that the species has very precise habitat requirements, favouring tall, dense, reedy vegetation growing in medium-sized or large, shallow freshwater wetlands. As Australasian bitterns are big, ›› The Australasian bittern has been sighted in rice fields in heavy birds, they do not feed by clinging onto vegetation like smaller southern New South Wales but little is known about why bitterns such as the Australian little bittern. Instead, they forage by wading through shallow water in search of fish, frogs and yabbies. This there are there. Research in northern Italy shows that over requirement for shallow water limits the amount of suitable habitat 25% of that country’s population of Eurasian bitterns breed available to them—if the water is too deep, the wetland becomes in rice crops. unsuitable. The bitterns’ reedy habitat is the key to their survival from potential predators. When a person walks through a bittern’s wetland, the bird’s typical reaction is to freeze and assume an erect posture— neck stretched taut and bill pointing skyward—making it difficult to see ›› A new project is being established by Birdlife Australia and the among the tall reeds. When this pose is combined with its remarkably RGA’s Environmental Champions Program, to see how many cryptic plumage (a striking ensemble of mottling, streaks and striations), a bittern is easily overlooked by most people and predators alike. bitterns are seeking out rice fields for habitat, and if the birds The presence of a bittern at any given wetland can be a seasonal are breeding there. thing. Wetlands in coastal south-eastern mainland Australia experience an increased reporting rate of bitterns in winter, while inland sites have higher reporting rates in spring and summer. This suggests that Australasian bitterns are mobile; moving hundreds of kilometres in search of suitable habitat. This is undoubtedly essential as their shallow ephemeral inland wetlands dry out in late summer. During the recent sustained drought in much of eastern Australia, most records of Australasian bitterns came from coastal wetlands, with south-western Victoria and south-eastern South Australia being particular strongholds for the species. It seems likely that these areas acted both as important drought refuges and wintering sites.

34 IREC Farmers’ Newsletter – Large Area No. 187: Spring 2012 resource management bitterns in rice fields

Breeding in the reeds however, a regular identification pitfall is the Nankeen night-heron in It is suspected that bitterns have strict breeding requirements. immature plumage. The night-heron is a smaller bird, with a noticeably Unfortunately, virtually nothing is known about the breeding biology hunched appearance and conspicuous rows of white spots on its of the Australasian bittern, with most of the relevant information upper wings. Its behaviour is different too, being less furtive than published over a century ago. the Australasian bittern, and rather than skulking among the reeds, it readily perches in trees, which an Australasian bittern almost never One feature of Australasian bitterns’ breeding habitat that is known does. In flight, the night-heron appears noticeably less ‘shaggy’ than an is not all wetlands that appear suitable for breeding actually support Australasian bittern, being slighter with narrower wings. breeding bitterns. It is also known that when setting up a breeding territory, male bitterns begin to give their distinctive, far-reaching, Rice & the Australasian bittern booming call, so that the presence of a booming male is thought to be Although many agricultural practices over the past century have been a good indication that a wetland is a suitable site for breeding. Listening detrimental for bitterns, there is one which in some instances seems to for these booming calls, which are sometimes audible for over a be having the opposite effect: rice farming. kilometre under the right conditions, is considered one of the most effective methods of detecting bitterns in their wetlands. The ponded fields from later October onwards, and the dense cover provided by the rice crop create an ideal habitat for Australasian bitterns. Bittern numbers in decline Australasian bitterns move into these crops during the growing season, Results of bittern surveys show that the population of the Australasian and males often establish their territories there. bittern has declined alarmingly. Armed with this information, Birdlife Research in northern Italy has revealed that over 25% of that country’s Australia nominated the species for listing as a threatened species under population of Eurasian bitterns breed in rice crops, but until now, there the Environment Protection and Biodiversity Conservation (EPBC) Act. As have been no studies which have examined the ecology of Australasian a result, the Australasian bittern was formally listed as ‘Endangered’ bitterns utilising rice crops in Australia. That may be about to change. in February 2010, bringing its national status in line with that of the This season, Birdlife Australia hopes to start a project which will go a IUCN’s Red List of Threatened Species. long way towards answering some of the many questions which arise from bitterns occurring in rice crops. Make no mistake! There is an urgent need to discover how many Australasian bitterns An Australasian bittern should be instantly recognisable with its large inhabit rice crops and whether or not they breed there. stocky build, long thick neck and brown-and-buff mottled plumage,

An Australasian bittern should be instantly recognisable with its large stocky build, long thick neck and brown-and-buff mottled plumage. Photo: Peter O’Connell, Birdlife Australia

IREC Farmers’ Newsletter – Large Area No. 187: Spring 2012 35 resource management bitterns in rice fields

Bitterns in rice project Through a partnership between Birdlife Australia and the RGA’s Environmental Champions Program, it was decided to develop a project brief for a Bitterns in Rice project and then both parties would seek funding from various organisations to finance the project. The first funding received for theBitterns in Rice project is from the Murrumbidgee Catchment Management Authority to Birdlife Australia under their Community Partnerships Program. Further funding has been secured from RIRDC and the Murray CMA and in-kind support from both Murray and Murrumbidgee CMAs, Murrumbidgee Field Naturalists Club, NSW National Parks and Wildlife Service, Murrumbidgee Irrigation and Coleambally Irrigation. There will much communication regarding this project as this year’s rice growing season approaches, however if you believe you see these birds prior to the season, please contact Neil Bull.

Further information Neil Bull Murray Regional Coordinator RGA Environmental Champions Program M: 0428 603 557 E: [email protected] Further information on Australasian bitterns can be found at: www.birdlife.org.au

An Australasian bittern in an MIA rice crop—a new project will look at the numbers of bitterns in rice fields and whether or not they are breeding there. Photo: David Webb, Birdlife Australia.

Australasian bitterns in a rice field near Deniliquin. Rice fields provide ideal habitat for bitterns whose natural habitats have been degraded or depleted by drought. Photo: John Hand, rice grower Murray Valley

36 IREC Farmers’ Newsletter – Large Area No. 187: Spring 2012