|Australian Bush Birds|
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|Brolga - Grus rubicunda|
|Brolgas at Boulia, western Queensland.|
The Brolga - Grus rubicunda - is an elegant, graceful bird standing about 1.8 metres tall. Overall colour is pale grey. It has a bare head with pale grey skin; eye yellow; ear coverts grey; scarlet on rear of head and nape; long, straight bill. Black 'haired' dewlap under chin. Neck and back silver-grey; back often has a brown wash. "Bustle" of secondary feathers falling over rump. Wings grey with black primaries. Underparts grey; legs dark grey-brown to black. No seasonal differences in plumage. Sexes similar; females slightly smaller.
|Brolga - page 2|
When encountering possible threats the brolga usually walks steadily away unless forced to fly. Flies with neck outstretched, broad wings have conspicuously fingered tips; slow, deliberate beat. Legs trail well behind tail-tip. Needs a run to take-off or takes off from hilltops.
Widespread and common in Northern and North Eastern Australia and coastal North Western Australia. A separate population (not a separate subspecies) exists in north-western Victoria, south-eastern South Australia and southern New South Wales. The southern population may be isolated from the northern one by unsuitable terrain. The southern population is threatened by loss of breeding habitat; the northern population appears to be expanding (due to increased use of croplands) in the Northern Territory, Kimberley and other parts of Western Australia.
Brolgas are non-migratory but move in response to seasonal rains. Their breeding season is determined by rainfall so occurs at different times of the year in monsoonal and temperate zones of Australia. Brolgas drink and bathe in the morning and evening and during the day in hot weather; they seek habitats in the vicinity of water and roost for the night in shallow water. Brolgas have a salt excreting gland near the eye and can drink salt water. Northern populations concentrate during the dry season in coastal freshwater wetlands where they are seen in pairs, in small family groups (parents and last season's juveniles) or in flocks of up to several hundred made up of numerous family groups.
In the dry season brolgas subsist on tubers of the bulkuru sedge (Eleocharis dulcis), often in competition with magpie-geese. Feeding areas are varied in this non-breeding times and may be far from water; brolgas are attracted to feed on burnt grassland and traditional dry season burning in the north was done to attract them as game. As well as tubers, they eat a variety of wetland plants (including cereal grain), insects, freshwater and saltwater molluscs, crustaceans, and frogs. Sites with very dense vegetation (in water or on land) are avoided.
When the Wet Season arrives, flocks break-up and pairs move out onto seasonal wetlands. Breeding is associated with elaborate dancing displays in the pair formation and bonding process; groups and pairs leap gracefully with wings outspread and head thrown back giving a carrying bugle call. Birds in the Northern population disperse to breeding sites in November or December and begin to build nests when the water levels rise in January when the wet begins. Egg-laying peaks in February-March. By June or July, when the wetlands are drying, families begin moving back towards coastal areas to re-form flocks.
|Brolga in flight|
For birds in the Southern population the breeding season extends from July to December; parents and young gather in traditional flocking areas from December to May. Bulkuru sedge does not grow south of Brisbane so Brolgas in the southern population have a more varied diet than northern ones.
Both sexes build the nest, sometimes a scrape in the ground but more usually a mound up to 1.5 metres in diameter of grass and sedge stems, built in densely vegetated wetlands. Nesting is not colonial, each pair defends a nesting territory up to 300 hectares containing one or several wetlands. Usually two eggs are laid. Both parents incubate the eggs which hatch after 28-31 days; both parents feed and guard the young, chicks can swim after 1-2 days and are fully feathered after about 13 weeks.
|Brolga - page 3|
Males can be very aggressive guarding the nest and family. Young birds stay with their parents for up to 11 months until the next breeding season. Full head and leg colouring develops over the next 2-3 years. Brolgas pair at 3-4 years and first breed successfully at 5 years of age. They pair for life and have been known to use the same nest areas for 20 years.
The Sarus Crane (Grus antigone) is similarly coloured, but is dark grey under the chin in place of the Brolga's dark coloured dewlap, and the red colouring on the Sarus Crane's head extends further down the neck. Sarus cranes live with Brolgas but do not interbreed. Sarus cranes are more wary and will fly from disturbance where Brolgas will walk. In the dry season Sarus cranes occupy drier areas than Brolgas provided they have access to water for drinking and bathing and secure roosting sites. Brolga and Saurus Crane ranges overlap in Queensland but there is no significant competition between the species. In the breeding season Brolgas prefer larger, more open wetlands while Saurus Cranes prefer smaller wetlands in more forested settings. Brolgas mainly dig-up and eat tubers in the dry season, Saurus Cranes feed on seeds and other surface food thus avoiding the Brolga's primary habitat in favour of croplands and disturbed habitats the Brolgas do not use by choice.