Breeding
Nesting takes place in winter. The male and female remain together for about five months, which includes courtship, nest building and egg-laying. The nest consists of a platform of grass on the ground, about 10 cm thick and 1 m - 2 m in diameter. The large eggs (130 mm x 90 mm) are laid at intervals of two to four days. These are dark bluish-green when fresh, becoming lighter with exposure to the sun. The shells are thick, with paler green and white layers under the dark outer layer.
The female dominates the male during pair formation but once incubation begins, the male becomes aggressive to other Emus, including his mate. The female wanders away and leaves the male to perform all the incubation. Sometimes she will find another mate and breed again. The male incubates the eggs without drinking, feeding, defecating or leaving the nest. During this time, eggs often roll out of the nest and are pulled back in by the male.
Newly hatched chicks are cream-coloured with dark brown stripes. They leave the nest when they are able to feed themselves. Young birds stay close together and remain with the male for four months. They finally leave at about six months. During this period, the stripes fade and the downy plumage is replaced by dull brown feathers. Emus are nearly fully grown at one year, and may breed at 20 months.
Sometimes eggs that have not hatched remain in the nest after the male and young have left and become sun-bleached. Bleaching takes about three months.
