Everything you always wanted to know about emu, the largest bird in Australia and the 2nd largest bird in the world.

"Be warned that the emu is armed and dangerous... OK, actually, it's footed and dangerous. ... If you spot the emu, please do not try to approach it as it uses its feet to defend itself. The feet have toenails that are like a knife and combined with its powerful legs, can cause severe injury."

Wikipedia - Emu

The emu (Dromaius novaehollandiae) is the second-largest living bird by height, after its ratite relative, the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus Dromaius. The emu's range covers most of mainland Australia, but the Tasmanian emu and King Island emu subspecies became extinct after the European settlement of Australia in 1788. The bird is sufficiently common for it to be rated as a least-concern species by the International Union for Conservation of Nature.

Emus are soft-feathered, brown, flightless birds with long necks and legs, and can reach up to 1.9 metres (6.2 ft) in height. Emus can travel great distances, and when necessary can sprint at 50 km/h (31 mph); they forage for a variety of plants and insects, but have been known to go for weeks without eating. They drink infrequently, but take in copious amounts of water when the opportunity arises.

Breeding takes place in May and June, and fighting among females for a mate is common. Females can mate several times and lay several clutches of eggs in one season. The male does the incubation; during this process he hardly eats or drinks and loses a significant amount of weight. The eggs hatch after around eight weeks, and the young are nurtured by their fathers. They reach full size after around six months, but can remain as a family unit until the next breeding season. The emu is an important cultural icon of Australia, appearing on the coat of arms and various coins. The bird features prominently in Indigenous Australian mythology.

Female emus court the males; the female's plumage darkens slightly and the small patches of bare, featherless skin just below the eyes and near the beak turn turquoise-blue. The colour of the male's plumage remains unchanged, although the bare patches of skin also turn light blue. When courting, females stride around, pulling their neck back while puffing out their feathers and emitting low, monosyllabic calls that have been compared to drum beats. This calling can occur when males are out of sight or more than 50 metres (160 ft) away. Once the male's attention has been gained, the female circles her prospective mate at a distance of 10 to 40 metres (30 to 130 ft). As she does this, she looks at him by turning her neck, while at the same time keeping her rump facing towards him. If the male shows interest in the parading female, he will move closer; the female continues the courtship by shuffling further away but continuing to circle him.[40][41]

If a male is interested, he will stretch his neck and erect his feathers, then bend over and peck at the ground. He will circle around and sidle up to the female, swaying his body and neck from side to side, and rubbing his breast against his partner's rump. Often the female will reject his advances with aggression, but if amenable, she signals acceptance by squatting down and raising her rump.[41][57]

Nest and eggs

Females are more aggressive than males during the courtship period, often fighting for access to mates, with fights among females accounting for more than half the aggressive interactions during this period. If females court a male that already has a partner, the incumbent female will try to repel the competitor, usually by chasing and kicking. These interactions can be prolonged, lasting up to five hours, especially when the male being fought over is single and neither female has the advantage of incumbency. In these cases, the females typically intensify their calls and displays.[41]

The sperm from a mating is stored by the female and can suffice to fertilise about six eggs.[57] The pair mate every day or two, and every second or third day the female lays one of a clutch of five to fifteen very large, thick-shelled, green eggs. The shell is around 1 mm (0.04 in) thick, but rather thinner in northern regions according to indigenous Australians.[3][56] The eggs are on average 13 cm × 9 cm (5.1 in × 3.5 in) and weigh between 450 and 650 g (1.0 and 1.4 lb).[58] The maternal investment in the egg is considerable, and the proportion of yolk to albumen, at about 50%, is greater than would be predicted for a precocial egg of this size. This probably relates to the long incubation period which means the developing chick must consume greater resources before hatching.[59] The first verified occurrence of genetically identical avian twins was demonstrated in the emu.[60] The egg surface is granulated and pale green. During the incubation period, the egg turns dark green, although if the egg never hatches, it will turn white from the bleaching effect of the sun.[61]

Emus have three toes on each footin a tridactyl arrangement, which is an adaptation for running and is seen in other birds, such as bustards and quails. The ostrich has two toes on each foot.

Size comparison between a human, the mainland emu (centre), and the extinct King Island sub-species (right)