The compost heap bird – Australian Brush-turkey

July 3, 2010 by
Filed under: Australian Birds 
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A Compost heap as big as a small car? Don’t be mistaken, this is size of the incubator for the eggs of the Australian Brush-turkey (Alectura lathami).

Australian Brush-turkey (Alectura lathami)

An Australian Bursh-turkey courtesy of kookr on Flickr

Brush-turkeys have been nesting in my backyard for several years now, and around the winter solstice the males begin to make their mound, or begin to remodel an existing mound in preparation to attract a female to mate with. The nests are built on the ground and are mounds built from leaves, sticks and practically anything loose on the ground including plastic bags, and rubbish. The mounds are commonly 4 meters across and 1metre high, although I have seen mounds that are nearly 2 meters high and 6 meters across. If a cubic metre of leaf mulch and stick weighs about 40kg, then a brush-turkey mound must weigh at least 640kg which is an impressive size for a birds nest!

Australian Brush-turkeys

Male and Female brush-turkey on a mound, the female is laying her egg in a hole dug by the male.

The female brush-turkeys lay their eggs inside the mound within a hole created by the male. Once the egg is laid, the male covers the egg with leaf litter and tends the mound. Instead of sitting on the eggs ans most birds do, the male brush-turkey incubates the eggs by adding or removing vegetation from the mound. The mound is like a giant compost heap in the sense that the vegetation in the mound begins to rot through microbial decomposition and begins to generate heat through the decompositional process. The male can adjust the heat of the mound by removing vegetation, thereby cooling the mound, or by adding vegetation to the mound which increases microbial activity and hence heats the mound. I’ve noticed that brush-turkeys are continually adjusting the amount of vegetation depending on whether the mound is exposed to sunlight and or moisture from rainfall.

The male brush-turkey uses his beak to determine the temperature of the mound, he sticks his head into the mound, hence the lack of feathers on his head. He can adjust the temperature of the mound to between 33-38 degrees Celsius. The brush-turkey eggs are quite large (12% of the females body weight) have a very high yolk content (67%), which allows the chick to be very well developed when it hatches after around 50 days in the mound.

Australian Brush-turkey chick

A young Brush-turkey chick not long out of the mound, courtesy of John Asquith

Chicks fall prey to cats, foxes, dogs, birds of prey and goannas. Goannas also dig into the mounds to eat the eggs. At around 3 weeks of age the chicks turn from brown to black and develop their adult plumages and males can begin to build mounds at 8 months of age. Chicks have to fend for themselves without any help from the parents when they dig themselves out of the mound and very quickly they can fly to avoid predators as they emerge from the mound with fully developed wing feathers.

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A roosting brush-turkey high in a tree. Courtesy of flagondry, flickr.

Brush-turkeys roost at night high in trees and roost communally and I have seen up to 20 birds in a single spotted-gum tree at Hardy’s Bay. Birds can travel large distances to roost and can make their way to the tops of trees which is quite a sight for such a large bird which spends most of its time on the ground.

Comments

Comments

One Response to “The compost heap bird – Australian Brush-turkey”
  1. Jeff Drudge says:

    Love it Doug!
    I miss my turkey mound outside my bedroom window at Killcare.

    Camping right now at Broken Head, with ten turkeys that come and visit at around six each morning and afternoon, trying to get into everything!!!! I still love them though.

    Despite the wildlife nuisances! I’m delighted to have the Mountain Brushtail possum in the tree outside our tent each night, and the Long-nosed Potoroo or Northern Brown Bandicoot that’s hopping round in the undergrowth outside too – I just wish I could getter better glimpse of it to tell which it is.

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