Definitions

megapode

megapode

[meg-uh-pohd]
megapode, common name for large, stout-bodied, long-tailed, terrestrial, nonmigratory birds comprising six genera in the family Megapodiidae. Members of the family have large, strong feet, hence the name megapode (from the Greek meaning "large foot"). Also called mound birds and incubator birds, they are remarkable in that they do not brood their eggs, but rather deposit them in mounds of earth and leaves and allow them to be incubated by the heat from the sun and from rotting vegetable material. The territory of each male contains a single mound, often the work of generations, reaching up to 15 ft (4.5 m) in height and 50 ft (15.2 m) in diameter. The male remains in the vicinity of the mound throughout the brood season, constantly checking and regulating the temperature by adding or removing material. The megapodes are commonly divided into three groups: the generally dullish-colored jungle fowl of the New Guinea rain forest, the blackish brush turkeys (e.g. Allectura lathami) of coastal Australia, and the reddish-brown, white-spotted Mallee fowl (Leipoa ocellata) of Australia's semiarid scrub region. Many megapode species were early carried by canoe to the South Pacific. Omnivorous, their diet includes insects, small animals, fruit, and seeds. Egg-laying details are well known for the Mallee fowl, which over a period of time in the early spring, deposits from 5 to 35 eggs. The eggs begin to incubate immediately, the heat inside the mound being carefully watched and regulated by the parents. This is accomplished by adding sand to cover the eggs if there is too much heat from the sun, or scratching it away, thereby increasing the amount of heat reaching the eggs. The Mallee fowl usually builds a new mound every year, unlike other members of the family. Megapodes are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Galliformes, family Megapodiidae.
The megapodes, also known as incubator birds or mound-builders, are stocky, medium-large chicken-like birds with small heads and large feet in the family Megapodiidae. They are terrestrial browsers. All but the Malleefowl occupy jungle habitats, and most are brown or black coloured. Megapodes are superprecocial, hatching from their eggs in the most mature condition of any birds. They hatch with open eyes, with bodily coordination and strength, with full wing feathers and downy body feathers, able to run, pursue prey, and, in some species, fly on the same day they hatch.

Breeding and nests

Megapodes do not incubate their eggs with their body heat as other birds do, but bury them. They are best known for building massive nest-mounds of decaying vegetation, which the male attends, adding or removing litter to regulate the internal heat while the eggs hatch. However, some bury their eggs in other ways: there are burrow-nesters which use geothermal heat, and others which simply rely on the heat of the sun warming sand. Some species vary their incubation strategy depending the local environment or the season. Although the Australian Brush-turkey is the only species of bird in which sex ratio is confirmed to be incubation-temperature dependent, it is speculated that this is common to all Megapodes, as they share nesting methods unique among birds. The non-social nature of their incubation raises questions as to how the hatchlings come to recognise other members of their species, which is due to imprinting in other members of the order Galliformes. Recent research suggests that there is an instinctive visual recognition of specific movement patterns made by the individual species of megapode.

Many are shy, solitary, and inconspicuous, others live in colonies of many thousands of birds.

Megapode chicks do not have an egg tooth: they use their powerful claws to break out of the egg, and then tunnel their way up to the surface of the mound, lying on their backs and scratching at the sand and vegetable matter. Similar to other precocious birds, they hatch fully feathered and active, already able to fly and live independently from their parents.

Distribution

Megapodes are found in the broader Australasian region, including islands in the western Pacific, Australia, New Guinea, and the islands of Indonesia east of the Wallace Line, but also the Andaman and Nicobar Islands in the Bay of Bengal.

Species

There are 21 species in 6 genera. Although the evolutionary relationships between the Megapodiidae are especially uncertain, the morphological groups are clear:

FAMILY: MEGAPODIIDAE

References

External links

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