BrolgaBrolga BreedingBreeding HabitatHabitat ManagingManaging WetlandsWetlands OnOn YourYour FarmFarm Matthew Herring Introducing Brolgas and their wetland habitat Wetlands are hotspots for biodiversity. They can support an incredibly diverse Brolgas are often concentration of life. A myriad of native seen feeding in birds, mammals, reptiles, frogs, fish, inver- paddocks and crop tebrates and plants depend on them for at stubble but for least part of their lifecycle, and ultimately breeding they rely for their survival. The much-loved Brolga on shallow wet- is one of those species. land areas that The Brolga is a large, charismatic wetland have low cover. bird of northern and eastern Australia, as Immature birds well as small parts of Papua New Guinea. lack the red head Adults can stand up to 1.4 metres and of adults until have a wingspan of over 2.5 metres. they’re about 18 Breeding pairs are thought to partner for months of age. life and it is likely that Brolgas can live for over 50 years in the wild. There are 15 species of crane in total and Brolgas are renowned for their elaborate they are recognised as one of the most ap- dancing displays and trumpeting calls dur- pealing yet most threatened bird groups on ing courtship and pair bonding. This capti- the planet. The Whooping Crane suffered a vating behaviour has been celebrated for severe population crash but has become many thousands of years through the an international symbol for successful con- dance and song of Indigenous Austra- servation, with recovery efforts in North lians. America turning imminent extinction around by boosting numbers from a low of 14 indi- The only other crane species found in viduals in 1938 to around 300 by 1999. Australia is the slightly larger Sarus Crane, an Indian-Asian species, which Brolgas have declined dramatically in has been recorded across northern Aus- south-eastern Australia since European tralia only since the mid-1960s, primarily settlement, primarily from habitat loss, in north Queensland. The White-faced shooting, poisoning, predation of young by Heron, common on Riverina farms, is Foxes and inappropriate wetland manage- sometimes incorrectly called a Blue ment. Apart from the odd vagrant, Brolgas Crane. Australia’s Two Crane Species: Together in the Gulf Country near Karumba, QLD, the three birds on the left are a Sarus Crane family, the three on the right are a Brolga family. Both species depend on wetlands for breeding. 2 There are fewer than 1000 Brolgas remaining in south-eastern Australia. Their survival ultimately depends on how wetlands are managed on farms. Ensuring there is breeding habitat for pairs like this one (with a chick less than one week old in tow) is the most important thing we can do to help save the Brolga. have now disappeared east of the Hume northern Victoria most pairs flock locally. Highway from Sydney to Melbourne. The Brolga is considered a threatened In south-eastern Australia, summer slowly species in the southern states, listed as dries their ephemeral breeding habitat and Vulnerable in Victoria, New South Wales Brolgas move to flocking sites. Here, we and South Australia. They are still consid- can measure recruitment by counting the ered secure nationally with 100 000 or number of immature birds among the more birds but recent Birds Australia Atlas adults. Since 2000 in the Riverina this has comparisons have shown strong evidence ranged from 0-5%, which is frighteningly for a nation-wide decline in the last 20 low compared to northern Australia where years. up to 15% is commonplace. Well managed wetlands like this There are now two core areas in south- Brolga breeding site in the Yarra- eastern Australia. The south-western Vic- wonga area support a wide range of torian group, which includes the far south- other waterbirds and wetland species. east of South Australia, supports around 650 birds. The Riverina group of northern Victoria and southern NSW supports fewer than 250 birds. Core breeding areas in the NSW Murray Catchment include the Urana, Jerilderie, Boree Creek, Lockhart, The Rock, Walbundrie, Oaklands, Saver- nake, Berrigan, Balldale, Corowa and Barooga regions. Most of these birds seem to use the Leeton and Colleambally flocking3 sites to the north each year. In Managing your wetland for Brolgas Flooding Regimes Breeding Brolgas like to Brolgas rely on shallow (~30 cm deep), ephemeral wetland areas for breeding. In maintain a the Riverina, breeding occurs between July panoramic view and December in response to winter/spring of their rainfall. Breeding wetlands range from en- environment. tirely ephemeral basin-type wetlands to the Tall, dense ephemeral edges of more permanent wet- vegetation is lands. Even farm dams for stock or irriga- avoided. tion storage that support extensive shal- lows with waterplants are used. rushes. Rice bays are only rarely used for The wetland vegetation in Brolga breeding breeding by Brolgas because the habitat is wetlands is rarely over 100 cm in height. generally available too late in the season. This is primarily as a result of a short flood- ing regime that never allows tall, dense Maintaining and restoring flows to the re- vegetation like Cumbungi to establish and maining shallow wetlands across the land- dominate. If tall vegetation or trees are pre- scape is a priority for Brolga conservation. sent, they are widely spaced or very Restoration can sometimes be as simple patchy, enabling Brolgas to maintain a as blocking a drain. panoramic view of their surrounds. Water depths at Brolga breeding wetlands aver- The NSW Murray Wetlands Working age about 30 cm. This also favours low Group, together with Murray Irrigation Lim- wetland plants like Spike-rushes and isn’t ited and numerous landholders have been deep enough to support reeds and tall instrumental in helping to restore wetlands Brolgas breed almost exclusively in ephemeral wetlands that are only flooded for about 2-6 months at a time, then allowed to completely dry out. They are usually large wetlands, between 10 and 200 hectares in area. 4 in the NSW Murray Catchment. The wa- tering private property wetlands project has flooded wetlands on over 100 farms since the project began in 2001. The re- sponse of waterbirds (including Brolgas) and an array of other native wetland spe- cies has been phenomenal. Grazing & Fire Regimes The vast majority of Brolga breeding sites in south-eastern Australia are on private land and are subject to grazing by sheep or cattle. Avoiding set stocking rates and allowing the area to be periodically rested from grazing are important general rules for wetland management. Excluding stock when the wetland is flooded will give wa- terplants the best chance to flourish and set seed. Canegrass and Cumbungi can form tall (2+ metres), thick stands. They are some- times burnt to promote grazing value by encouraging new, succulent shoots that are palatable to stock. Such management can be beneficial to Brolgas. Foxes and Poor Breeding Success It has become clear over the past 7 years in the Riverina that the vast majority (70- 90%) of Brolga breeding attempts fail. These Spike-rushes (above, Eleocharis Although direct evidence is usually lack- species) respond quickly to shallow ing, Foxes are presumed to be responsi- ble for most chicks disappearing within the flooding (5-50 cm). The underground first few weeks of hatching. tubers are a favoured food source of Brolgas. A long fledging period of around 95 days Cumbungi (below, Typha species) pre- leaves young Brolgas grounded for much fers deeper, more permanent flooding, longer than most ground nesting birds. especially over summer. The lack of Foxes across northern Austra- lia is probably at least partly responsible for the relatively healthy Brolga popula- tions still present there. The poor breeding success could also be attributable to poor habitat quality, result- ing in starvation, malnutrition, a lack of cover against predators or the need to wander further to find food. Strategic bait- ing programs like those undertaken by the Rural Lands Protection Board that involve multiple farms, together with improved management of breeding wetlands should see5 Brolga breeding success improve. These Canegrass ( Eragrostis australasica ) and Spike-rush ( Eleocharis species) wetlands in the Urana, Boree Creek and Balldale regions are typical of Brolga breeding sites across the New South Wales and Victorian Riverina. They are treeless, ephemeral wetlands that explode with life when flooded. Water depths average about 30 cm and they are usually flooded for between 2 and 6 months. The vegetation is typically below 100 cm in height. The pair opposite are chang- ing over incubation duties. The two eggs hatch in around 30 days. The chicks are not capable of flying for another 95 days, leaving them grounded and vulnerable to predation by foxes. 6 7 Wetlands With Trees Brolgas are generally only recorded utilis- ing River Red Gum ( Eucalyptus camaldu- lensis) or Black Box ( Eucalyptus lar- giflorens ) wetlands with a canopy cover of 10% or below, and usually lower than 5%. These sites have large, mature, well- spaced trees, together with shallow, open areas with emergent vegetation. Several naturally-open remnant wetlands in the Riv- erina have been planted with River Red Gums in recent years, making them unsuit- able for Brolgas. River Red Gum wetlands like the Walla In the extensive red gum forests of the Riv- Walla Swamp pictured here are suitable erina (e.g. Barmah-Millewa forest) Brolgas as Brolga breeding sites only if there are have essentially disappeared. Forestry at least some open areas with well- practices have increased tree density and spaced trees. young trees have invaded open wetland areas because altered river levels have re- Powerlines and Fencelines duced the depth and duration of flooding in winter-spring, and increased summertime flooding, favouring mass-germination.