Moundbuilders: Megapodiidae

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MOUNDBUILDERS: Megapodiidae

MALLEEFOWL (Leipoa ocellata): SPECIES ACCOUNTS
MALEO (Macrocephalon maleo): SPECIES ACCOUNTS

PHYSICAL CHARACTERISTICS

Moundbuilders have big, strong legs and feet. The short bill curves downward, and most moundbuilders look like other galliforms (members of the order Galliformes) in body shape and dull coloring. There are a few species that have patterned plumage (feathers), but in these birds, the patterning helps conceal them from predators.

Moundbuilders weigh between 1.1 and 5.5 pounds (0.5 to 2.5 kilograms) and measure 11 to 27 inches (28 to 70 centimeters) in length.

GEOGRAPHIC RANGE

Primarily in Australia and New Guinea as well as on islands throughout the southeastern Pacific and Southeast Asia.

HABITAT

Moundbuilders must live in regions where climate conditions encourage the decomposition of organic matter, and so they prefer tropical and subtropical rainforests. Only the malleefowl and the Australian brush-turkey can be found in habitats outside the rainforest.

DIET

Most of what moundbuilders eat comes from the forest floor. These birds feed on fallen fruits, seeds, ants, scorpions, and even small snakes. Although most of this food gets eaten as the birds dig through forest leaf-litter, they do seek out specific types of food, fruit being one of these.

BEHAVIOR AND REPRODUCTION

It's difficult to separate reproduction behavior from other behavior because nearly all aspects of life among moundbuilders revolve around their incubation (keeping eggs warm for hatching) methods. The moundbuilder family is vocal, and calls range from low-pitched and quiet to incredibly loud and wail-like.

Unlike other birds, moundbuilders do not use their body heat to incubate their eggs. Instead, they rely on solar radiation (on beaches), geothermal activity (from soil near volcanic areas), and the decomposition of organic matter (in mounds). Mounds consist of leaf-litter and soil, and adults constantly add fresh material to conserve moisture. Some species dig burrows rather than build mounds, and their eggs are incubated by the sun or geothermal sources (sand, soil). Clutch sizes range from twelve to thirty eggs each season and must incubate for forty-five to seventy days.

CAUGHT ON FILM

For the first time ever, the threatened Vanuatu (van-wah-TOO) megapode was captured on film by Dr. Mark O'Brien in December 2003. O'Brien, a researcher from the Royal Society for the Protection of Birds, had visited the Pacific nation of Vanuatu so that he could work with the chief in an effort to determine a way that islanders could still harvest eggs, but in a sustainable way.

According to a press release posted on Birdlife.org, only 2,500 pairs of Vanuatu megapodes remain, and only on the 108 islands of Vanuatu. As a result of O'Brien's visit, the chief initiated a conservation program that included a moratorium (temporary halt) on egg collection that lasted four months. Anyone disobeying the rule was fined $135 or the equivalent in pigs or cattle. And because the species is rarer in the southeastern part of the nation, those communities agreed to a five-year ban on egg collection.

O'Brien acknowledged that another visit to Vanuatu is necessary to learn the effects of the moratorium.

Moundbuilders lay their eggs in individual holes deep within the incubation site, and each chick hatches separately, without help from the parents. Chicks dig for two to fifteen hours to reach the surface, and they are completely independent at the time of hatching. This means they leave the site, find food and water, recognize and avoid predators, animals that hunt them for food, and even regulate their own body heat upon birth.

Some moundbuilders are monogamous (muh-NAH-guh-mus; having only one mate) while others are polygynous (puh-LIH-juh-nus; one male, several females). Predators include foxes, birds of prey, dingoes, and wild cats.

MOUNDBUILDERS AND PEOPLE

Humans have traditionally harvested the birds' eggs, which are rich in protein. Although native people have been harvesting eggs for thousands of years, the recent human population growth has proven to be more than the moundbuilder population can sustain, and overharvesting has become a serious problem.

CONSERVATION STATUS

Almost half of the twenty-two species face some level of threat. Six species are listed as Vulnerable by the IUCN, facing a high risk of extinction, dying out, while one is Critically Endangered, facing an extremely high risk of extinction, and another two are Endangered, facing a very high risk of extinction. One species is Near Threatened, at risk of becoming threatened. The main reasons for threat include habitat loss, overharvesting of eggs, and predation by introduced animals.

MALLEEFOWL (Leipoa ocellata): SPECIES ACCOUNTS

Physical characteristics: Both sexes grow to be around 23.6 inches (60 centimeters) long. Males weigh 4 to 5.5 pounds (1.8 to 2.5 kilograms) while females weigh 3.3 to 4.5 pounds (1.5 to 2 kilograms). Upperparts have a distinct stripe pattern of white, black, and gray. Stripes are made up of spots that resemble eyes, which help to ward off predators.

Geographic range: Found in Australia, primarily in the southern states. Recently rediscovered in the deserts of central Australia.

Habitat: Malleefowl live among eucalyptus (yoo-kah-LIP-tus) trees and the spiny, shrub-like acacia (uh-KAY-shah) woodlands.

Diet: The malleefowl feed on plants, especially seeds and fruits. About 20 percent of their diet is comprised of ground-dwelling in-vertebrates (animals without backbones). They'll drink water if it's available, but don't require it.

Behavior and reproduction: Malleefowl are territorial and pairs will defend their incubation mound. Despite being monogamous, they are solitary (lone) birds, and males will remain near the mound while fe-males wander. These birds rarely fly, but they roost (rest) in the safety of trees.

Malleefowl are ready to mate between the ages of two to four years, and they continue breeding until the age of twenty years or so. Males spend up to eleven months each year building the incubation mounds and tending to them. One mound is used for numerous generations. Females lay two to thirty-four eggs at intervals of two to seventeen days, depending upon the weather. The drier the season, the longer the laying time between eggs. Incubation lasts fifty-five to seventy-seven days, depending on the temperature of the mound. Male malleefowl determine mound temperature by dipping their beaks into the mound. Malleefowl live to be about thirty years old. Foxes and wild cats are the primary predators, and the mortality rate of eggs is very high.

Malleefowl and people: Wheat farming encroaches upon the habi-tat of the malleefowl, and sheep grazing threatens the malleefowl's food sources.

Conservation status: Classified as Vulnerable due to habitat destruction and the predation of introduced animals. ∎

MALEO (Macrocephalon maleo): SPECIES ACCOUNTS

Physical characteristics: Maleos grow to 21.7 inches (55 centime-ters) long. Females weigh slightly more (3.3 to 3.9 pounds, or 1.5 to 1.8 kilograms) than males (2.9 to 3.5 pounds, or 1.3 to 1.6 kilograms). This large bird has deep black upperparts and underparts that are white tinged with pink. The head is topped with a black "helmet."

Geographic range: The maleo is found on Sulawesi in Indonesia.

Habitat: Maleos live in tropical forests as well as plantations.

Diet: The maleo feeds on a variety of fruits and seeds. Also eats cockroaches and other invertebrates found on the forest floor.

Behavior and reproduction: The maleo is a shy bird. Monogamous pairs will not leave each other and will defend their burrows from other pairs.

Rather than building a mound out of the soil, this species burrows or tunnels into the soil. Both sexes participate in burrowing and tending to the site. Eggs are laid 4 to 40 inches (10 to 100 centimeters) deep, with ten to twelve days in between each egg. Eggs are five times the size of chicken eggs.

Maleos and people: Natives of Sulawesi have harvested maleo eggs for centuries.

Conservation status: Classified as Vulnerable due to population decline. The increase in human population has caused overharvesting of maleo eggs. ∎

FOR MORE INFORMATION

Books:

Jones, Darryl N., et al. The Megapodes: Megapodiidae. Oxford, U.K.: Oxford University Press, 1995.

Periodicals:

"Megapode Captured On Film for First Time." BirdLife International (December 19, 2003). Online at http://www.birdlife.org/news/news/2003/12/vanuatu_megapode.html (accessed on June 2, 2004).