..by Matthew Herring, was published in a special Wetlands edition of Wingspan, membership magazine of Birds Australia (Vol. 14:4 December 2004). The original text is reproduced by permission (layout and images by Ozcranes). Matt is the southern Australia representative for the Australian Crane Network.
Brolgas breed as separate pairs in the wettest season, July to December in southern Australia, and flock together near wetlands in drier months. In Part 1, Matthew outlines the serious inroads made into southern Australian Brolga numbers by wetland loss, historical persecution and foxes. In Part 2, he reveals important steps for wetland management and key support from southern farmers for Brolga conservation.
by Matthew Herring
Southern Brolgas are losing their step; improved wetland management aims to return them to form.
Part 1 | A national icon: trouble in the south
I doubt many birdwatchers tire of the iconic Brolga, arguably Australia's most treasured waterbird. Whether a breeding pair calling in unison, a lively group on a wetland dance floor, or a graceful flock sailing overhead, Brolgas seem to capture our attention effortlessly.
Fortunately, it is thought that the total remaining Brolga population may number 100,000 or even higher. The vast bulk of these occupy the extensive wetlands and plains of northern Australia, in core areas such as the Atherton Tableland, the Gulf Country, Mount Isa region, Kakadu National Park and parts of the Kimberley. Smaller numbers occur in (Papua) New Guinea, as well as south throughout most of Queensland, spilling into the far north-east of South Australia and across parts of northern New South Wales. Further south, however, Brolgas are in serious trouble.
Falling southern population Brolgas are considered a threatened species in South Australia, Victoria and New South Wales. Once common enough to be regarded as a widespread pest of crops, the southern population has been reduced to alarmingly low numbers. We now know that in total there are fewer than 1,000 birds scattered across south-western Victoria, the far south-east of South Australia, and the New South Wales and Victorian Riverina. Central New South Wales is almost devoid of Brolgas, largely isolating the southern population from its northern counterpart.
Brolgas are now extinct in the Upper Murray River Region, the plains east of Melbourne through Gippsland and elsewhere in south-eastern Australia. In Victoria, breeding now only occurs as far east as Werribee and Rutherglen. In fact, Brolgas have become near impossible to find east of the Hume Highway, which stretches from Sydney to Melbourne. Landholders report continuing local declines in recent decades. The main drivers behind these southern declines are thought to be wetland loss, historic shooting and poisoning campaigns, and predation of young by the introduced fox.
← Adult Brolga guards twin chicks, an unusual sight in southern Australia (Ian Montgomery)
Poor recruitment As the south-eastern Australian summer slowly dries their ephemeral breeding habitat, Brolgas flock together at non-breeding sites, usually within 40 km. Such sites include a wetland with minimal disturbance and open, shallow water for roosting, surrounded by extensive crop stubble and paddocks for foraging. These spectacular Brolga gatherings provide an excellent opportunity to measure recruitment, simply by counting the flock and the number of immature birds. Not surprisingly, the count varies from year to year. For example, in the Riverina, in the year 2000 there were six immature birds among a total of 137 Brolgas (4 per cent) but none amongst 123 present in 2003, after a drought. Being such a long-lived species you'd be tempted to think these sorts of figures might be sufficient to maintain a viable population. But frighteningly, recruitment in southern Brolgas is typicaly about one quarter or less than that of Brolgas in the north, where up to 15 per cent is commonplace.