Megapode

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Megapode
Australian brushturkey (Alectura lathami) female Atherton.jpg
female Australian brushturkey (Alectura lathami)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Galliformes
Family: Megapodiidae
Lesson, 1831
Genera
Brushturkeys can often be found in parks or gardens. Australian brushturkey (Alectura lathami) female head Atherton.jpg
Brushturkeys can often be found in parks or gardens.

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. Their name literally means "large foot" and is a reference to the heavy legs and feet typical of these terrestrial birds. All are browsers, and all except the malleefowl occupy wooded habitats. Most are brown or black in color. Megapodes are superprecocial, hatching from their eggs in the most mature condition of any bird. They hatch with open eyes, bodily coordination and strength, full wing feathers, and downy body feathers, and are able to run, pursue prey and, in some species, fly on the day they hatch. [1]

Contents

Etymology

From the Greek μέγας (mégas = great) and πούς, (poús = foot). [2]

Description

Megapodes are medium-sized to large terrestrial birds with large legs and feet with sharp claws. Megapodes are of three kinds: scrub fowl, brush turkeys, and mallee fowl or lowan. The largest members of the clade are the species of Alectura and Talegalla . The smallest are the Micronesian scrubfowl (Megapodius laperouse) and the Moluccan scrubfowl (Eulipoa wallacei). They have small heads, short beaks, and rounded and large wings. Their flying abilities vary within the clade. They present the hallux at the same level of the other toes just like the species of the clade Cracidae. The other Galliformes have their halluces raised above the level of the front toes. [3]

Distribution and habitat

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. The distribution of the family has contracted in the Pacific with the arrival of humans, and a number of island groups such as Fiji, Tonga, and New Caledonia have lost many or all of their species. Raoul Island, a New Zealand territory and the main island of the Kermadec Islands, may also have once had a species of megapode, based on settler accounts. [4]

Behaviour and ecology

Australian brushturkey on its mound Brushturkeykansaszoo.jpg
Australian brushturkey on its mound

Megapodes are mainly solitary birds that do not incubate their eggs with their body heat as other birds do, but bury them. Their eggs are unusual in having a large yolk, making up 50–70% of the egg weight. [5] The birds 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 develop. 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 the sand. Some species vary their incubation strategy depending on the local environment. [4]

Although the Australian brushturkey was thought to exhibit temperature-dependent sex determination, this was later proven false; [6] temperature does, however, affect embryo mortality and resulting offspring sex ratios. The nonsocial 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. Research suggests an instinctive visual recognition of specific movement patterns is made by the individual species of megapode. [7]

This cross-section of a megapode mound shows a layer of sand (up to 1 m thick) used for insulation, an egg chamber, and a layer of rotting compost. The egg chamber is kept at a constant 33degC by opening and closing air vents in the insulation layer, while heat comes from the compost below. Malleefowl Pengo.svg
This cross-section of a megapode mound shows a layer of sand (up to 1 m thick) used for insulation, an egg chamber, and a layer of rotting compost. The egg chamber is kept at a constant 33°C by opening and closing air vents in the insulation layer, while heat comes from the compost below.

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 superprecocial birds, they hatch fully feathered and active, already able to fly and live independently from their parents. [5] In megapodes superprecociality apparently evolved secondarily from brooding and at least loose parental care as more typical in Galliformes. [8] Eggs previously assigned to Genyornis have been reassigned to giant megapode species. Some dietary and chronological data previously assigned to dromornithids may instead be assigned to the giant megapodes. [9]

Megapodes share some similarities to the extinct enantiornithes in terms of their superprecocial life cycle, though also several differences. [lower-alpha 1]

Species

The more than 20 living species are placed in seven genera. Although the evolutionary relationships between the Megapodiidae are especially uncertain, the morphological groups are clear: [11]

Phylogeny

Megapodiidae

Macrocephalon – maleo

Eulipoa – Moluccan megapode

Megapodius – scrubfowl (12 species)

Leipoa – malleefowl

Talegalla – brushturkeys (3 species)

Alectura – Australian brushturkey

Aepypodius – brushturkeys (2 species)

Phylogeny of the Megapodiidae based a study by Chen, Hosner, Dittmann, et al. (2021). [12] The numbers of species are from the IOU list by Gill, Donsker, & Rasmussen. [13]

Taxonomy

Human uses

In their native Oceania, indigenous peoples protect their nesting sites, as their eggs are considered to be delicacies. [14] Their eggs are about twice the size of chicken eggs and the yolks are roughly four times as massive. [15]

See also

Footnotes

  1. "These feather traces and the plumage in HPG-15-1 strongly suggest that members of the Enantiornithes were born fully fledged and capable of flight soon after hatching, somewhat resembling the super-precocial megapodes, the only group of neornithines in which neonates are similarly born fledged and capable of flight (Zhou and Zhang, 2004; Jones and Göth, 2008; Xing et al., 2017). Megapodes do not fly immediately, requiring nearly two days to dig themselves out of their mounds during which they preen off their feather sheaths and let their feathers dry (Jones and Göth, 2008). Similarly, hatchling enantiornithines would have had to wait until their feather sheaths were removed and their feathers dry before attempting flight. Although ecological and behavioural differences clearly exist between enantiornithines and megapodes (e.g., enantiornithines were arboreal and not mound-nesters), megapodes represent the precocial extreme in extant neornithines and thus the closest analogue for enantiornithine development, for which all evidence indicates a form of extreme precociality (Elzanowski, 1981; Zhou and Zhang, 2004; Xing et al., 2017)." [10]

Related Research Articles

<span class="mw-page-title-main">Galliformes</span> Order of heavy-bodied ground-feeding birds

Galliformes is an order of heavy-bodied ground-feeding birds that includes turkeys, chickens, quail, and other landfowl. Gallinaceous birds, as they are called, are important in their ecosystems as seed dispersers and predators, and are often reared by humans for their meat and eggs, or hunted as game birds.

<span class="mw-page-title-main">Australian brushturkey</span> Species of bird

The Australian brushturkey, Australian brush-turkey, or gweela, also frequently called the scrub turkey or bush turkey, is a common, widespread species of mound-building bird from the family Megapodiidae found in eastern Australia from Far North Queensland to Eurobodalla on the South Coast of New South Wales. The Australian brushturkey has also been introduced to Kangaroo Island in South Australia. It is the largest extant representative of the family Megapodiidae, and is one of three species to inhabit Australia.

<span class="mw-page-title-main">Nicobar megapode</span> Species of bird

The Nicobar megapode or Nicobar scrubfowl is a megapode found in some of the Nicobar Islands (India). Like other megapode relatives, it builds a large mound nest with soil and vegetation, with the eggs hatched by the heat produced by decomposition. Newly hatched chicks climb out of the loose soil of the mound and being fully feathered are capable of flight. The Nicobar Islands are on the edge of the distribution of megapodes, well separated from the nearest ranges of other megapode species. Being restricted to small islands and threatened by hunting, the species is vulnerable to extinction. The 2004 tsunami is believed to have wiped out populations on some islands and reduced populations on several others.

<span class="mw-page-title-main">Dusky megapode</span> Species of bird

The dusky megapode, also known as dusky scrubfowl or common megapode, is a medium-sized, approximately 41 cm long, blackish bird with a short pointed crest, bare red facial skin, dark legs, brown irises, and a dark brown and yellow bill. The male and female are similar. This terrestrial species lives in forests and swamps, including mangroves, of the Maluku and Raja Ampat Islands in Indonesia. Like other megapodes, it lays its eggs in a mound made from earth mixed with leaves, sand, gravel, and sticks, which can be as large as 11 m (36 ft) in diameter and stand nearly 5 m (16 ft) tall.

<span class="mw-page-title-main">Orange-footed scrubfowl</span> Species of bird

The orange-footed scrubfowl, also known as orange-footed megapode or just scrubfowl, is a small megapode of the family Megapodiidae native to many islands in the Lesser Sunda Islands as well as southern New Guinea and northern Australia.

<span class="mw-page-title-main">Micronesian megapode</span> Species of bird

The Micronesian megapode or Micronesian scrubfowl is an endangered megapode which inhabits islands of the Western Pacific Ocean.

<span class="mw-page-title-main">Moluccan megapode</span> Species of bird

The Moluccan megapode, also known as Wallace's scrubfowl, Moluccan scrubfowl or painted megapode, is a small, approximately 31 cm long, olive-brown megapode. The genus Eulipoa is monotypic, but the Moluccan megapode is sometimes placed in Megapodius instead. Both sexes are similar with an olive-brown plumage, bluish-grey below, white undertail coverts, brown iris, bare pink facial skin, bluish-yellow bill and dark olive legs. There are light grey stripes on reddish-maroon feathers on its back. The young has brownish plumage, a black bill, legs and hazel iris.

<span class="mw-page-title-main">Sula megapode</span> Species of bird

The Sula megapode or Sula scrubfowl is a species of bird in the family Megapodiidae. It is found only in the Banggai and Sula Islands between Sulawesi and the Maluku Islands in Indonesia, where its habitats are subtropical or tropical dry forest, subtropical or tropical moist lowland forest, subtropical or tropical mangrove forest, and subtropical or tropical moist shrubland. It is threatened by habitat destruction.

<span class="mw-page-title-main">Philippine megapode</span> Species of bird

The Philippine megapode, also known as the Philippine scrubfowl or the Tabon scrubfowl, is a species of bird in the family Megapodiidae. It is found in the Philippines, northeastern Borneo, and Sulawesi. It has a wide range of natural habitats which include tropical dry forest, tropical moist lowland forest, tropical moist montane forest and small islands. The species was named after the collector Hugh Cuming.

<span class="mw-page-title-main">Melanesian megapode</span> Species of bird

The Melanesian scrubfowl or Melanesian megapode is a megapode species that is endemic to islands within Melanesia. The Melanesian scrubfowl has a unique strategy of egg incubation in which it relies on environmental heat sources. This bird species is culturally important for Indigenous peoples in Melanesia.

<span class="mw-page-title-main">Vanuatu megapode</span> Species of bird

The Vanuatu megapode or Vanuatu scrubfowl is a species of bird in the family Megapodiidae. It was formerly known as the New Hebrides scrubfowl. It is found only in Vanuatu. Its natural habitat is subtropical or tropical moist lowland forest. The species is threatened by habitat loss and egg collecting.

<span class="mw-page-title-main">Scrubfowl</span> Genus of birds

The scrubfowl are the genus Megapodius of the mound-builders, stocky, medium-large chicken-like birds with small heads and large feet in the family Megapodiidae. They are found from south-east Asia to north Australia and islands in the west Pacific.

The Tanimbar megapode or Tanimbar scrubfowl is a small megapode endemic to the Tanimbar Islands of Indonesia. It is sometimes considered to be a subspecies of the orange-footed scrubfowl, Megapodius reinwardt.

<span class="mw-page-title-main">Brushturkey</span> Index of animals with the same common name

Brushturkey, brush-turkey or brush turkey generally refer to birds in three genera in the megapode family, and sometimes to other species such as the Australian bustard:

The Viti Levu scrubfowl, also known as the Fiji scrubfowl or lost megapode, is an extinct megapode that was endemic to Fiji. The epithet amissus, from Latin "lost", refers to its extinction. Subfossil remains were collected from the Udit cave at Wainibuku on the island of Viti Levu in October 1998 by Trevor Worthy, G. Udy and S. Mataraba, and described by Worthy in 2000. The holotype is held by the Museum of New Zealand.

Megavitiornis altirostris is an extinct, flightless, giant stem-galliform bird that was endemic to Fiji, it is the only known species in the genus Megavitiornis. Originally thought to be a megapode, more recent morphological studies indicate a close relationship with Sylviornis of New Caledonia, with both genera belonging to the family Sylviornithidae outside of the Galliformes crown group. It is likely that it became extinct through overhunting shortly after the colonisation of the Fiji Islands by humans.

The consumed scrubfowl is an extinct megapode that was native to Fiji and Tonga in the south-west Pacific Ocean. It was originally described from subfossil remains collected by David Steadman from an archaeological site at Tongoleleka, on the island of Lifuka in the Haʻapai group of the Kingdom of Tonga. The specific epithet and vernacular name refer to its evident use as a food item. Subsequently, remains were also found on Lakeba and Mago in the Lau group of Fiji by Trevor Worthy. It likely became extinct through overhunting following human settlement of the islands some 3,500 years ago but may have persisted until the mid-late 19th century:

<span class="mw-page-title-main">Giant malleefowl</span> Extinct species of bird

Progura is an extinct genus of megapode that was native to Australia. It was described from Plio-Pleistocene deposits at the Darling Downs and Chinchilla in southeastern Queensland by Charles De Vis.

<span class="mw-page-title-main">Precociality and altriciality</span> States of newborn mobility and independence

Precocial species in birds and mammals are those in which the young are relatively mature and mobile from the moment of birth or hatching. They are normally nidifugous, meaning that they leave the nest shortly after birth or hatching. Altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. These categories form a continuum, without distinct gaps between them.

References

  1. Starck, J.M. & Ricklefs, R.E. (1998). Avian Growth and Development: Evolution within the altricial precocial spectrum. New York, NY: Oxford University Press. ISBN   978-0-19-510608-4.
  2. Newton, Alfred (1911). "Megapode"  . In Chisholm, Hugh (ed.). Encyclopædia Britannica . Vol. 18 (11th ed.). Cambridge University Press. p. 75.
  3. del Hoyo, J.; Elliott, A.; Sargatal, J. (1994). Handbook of the Birds of the World . Vol. 2: New World Vultures to Guineafowl. Lynx Edicions. ISBN   978-84-87334-15-3.
  4. 1 2 Steadman, D. (2006). Extinction and Biogeography in Tropical Pacific Birds. University of Chicago Press. ISBN   978-0-226-77142-7.
  5. 1 2 Starck, J.M. & Sutter E. (2000). "Patterns of growth and heterochrony in moundbuilders (MEgapodiidae) and fowl (Phasianidae)". Journal of Avian Biology. 31 (4): 527–547. doi:10.1034/j.1600-048x.2000.310413.x.
  6. Göth, Ann & Booth, David T. (22 March 2005). "Temperature-dependent sex ratio in a bird". Biology Letters. 1 (1): 31–33. doi:10.1098/rsbl.2004.0247. PMC   1629050 . PMID   17148121.
  7. Göth, A. & Evans, C.S. (2004). "Social responses without early experience: Australian brush-turkey chicks use specific visual cues to aggregate with conspecifics". Journal of Experimental Biology. 207 (13): 2199–2208. doi: 10.1242/jeb.01008 . PMID   15159424.
  8. Harris, R.B.; Birks, S.M.; Leaché, A.D. (2014). "Incubator birds: Biogeographical origins and evolution of underground nesting in megapodes (Galliformes: Megapodiidae)". Journal of Biogeography. 41 (11): 2045–2056. doi:10.1111/jbi.12357. S2CID   53532720.
  9. Worthy, Trevor H. (13 January 2016). "A case of mistaken identity for Australia's extinct big bird". theconversation.com.
  10. O'Connor, Jingmai; Falk, Amanda; Wang, Min; Xiao-Ting, Zheng (3 January 2020). "First report of immature feathers in juvenile enantiornithines from the Early Cretaceous Jehol avifauna". ResearchGate. Project: Vertebrata PalAsiatica. doi:10.19615/j.cnki.1000-3118.190823.
  11. Birks, S.M. & Edwards, S.V. (2002). "A phylogeny of the megapodes (Aves: Megapodiidae) based on nuclear and mitochondrial DNA sequences". Molecular Phylogenetics and Evolution. 23 (3): 408–421. doi:10.1016/s1055-7903(02)00002-7. PMID   12099795.
  12. Chen, D.; Hosner, P.A.; Dittmann, D.L.; O’Neill, J.P.; Birks, S.M.; Braun, E.L.; Kimball, R.T. (2021). "Divergence time estimation of Galliformes based on the best gene shopping scheme of ultraconserved elements". BMC Ecology and Evolution. 21 (1): 209. doi: 10.1186/s12862-021-01935-1 . PMC   8609756 . PMID   34809586.
  13. Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (July 2021). "Pheasants, partridges, francolins". IOC World Bird List (Version 11.2 ed.). International Ornithologists' Union . Retrieved 23 November 2021.
  14. Microlivestock: Little-known small animals with a promising economic future. National Academies Press. 1991. p. 170-171. doi:10.17226/1831. ISBN   978-0309042956 . Retrieved 5 April 2022.
  15. Cocker, Mark. "The Lava Birds" (PDF). Tourism Solomons. Retrieved 5 April 2022.