Mallee fowl

The mallee fowl is an extraordinary bird that lives in semi-arid parts of southern Australia, notably the mallee scrublands (composed of dwarf eucalypts) from which it takes its name. Although this bird is not particularly noteworthy in appearance, its breeding behaviour makes it remarkable.

The mallee fowl belongs to the megapode group of birds, most of which are forest dwellers and are characterised by building mounds for their nests. However, the mallee fowl has adapted to living in more open environments.

Appearance

The mallee fowl (Leipoa ocellata) is a large bird, some 60 centimetres (24 inches) in length. The head and neck are greyish, with a black crest. The wings are barred and the upperparts are also heavily barred with black, brown, white and grey markings. The underparts are a more uniform grey with a dark line running down the chest. Males and females are similar in appearance.

Behaviour

The mallee fowl is not a great flyer, preferring to spend most of its time on the ground and only flapping with some effort into trees and bushes to roost.

It spends the day foraging for fruits, vegetation and insects.

Breeding

The breeding season is from September to April. The birds build a large mound – up to four feet high and 14 feet across – that consists of vegetable matter that is then covered in soil. As the vegetation rots it creates heat, and this is used to incubate the eggs. A hole is made in the top of the mound, in which the hen bird lays between 15 and 24 eggs at 6-day intervals. The male bird then assumes responsibility for temperature control, either covering the eggs or exposing them to the air. He tests the temperature with his mouth lining and tongue, ensuring that the eggs never vary more than one degree from the ideal level, which is 33 Celsius (91 Fahrenheit).

The process is a long one, taking as much as eight months from the initial laying to the final hatching. No other bird species is known to be able to achieve such a degree of thermal engineering, although not every egg produces a live chick and the failure rate can be as high as 50%.

On hatching, the chicks dig their own way out of the mound and are then completely on their own, getting no support from their parents. They fledge at about one week.

The mallee fowl has clearly evolved in a way that works, although the contrast between intense care for the eggs and none for the chicks may strike one as bizarre. The main threat to the mallee fowl comes from habitat destruction.

© John Welford