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The Micronesian Megapode is
a pigeon-sized bird with an average weight of about 12.25
ounces (3.8 grams). It has a dark gray-brown to black body
plumage and an ash gray head with a slightly darker, short,
rough crest. |
The flight feathers and short tail are grayish-black,
and the wings are short and round. The bill is yellow with the upper
mandible clove-brown to black at the base. The feathers around the
eye, ear, and throat are very sparse or absent revealing red skin
and a red throat patch. The heavily built legs and feet are yellow
with the joints of toes and/or all the upper surface dark gray-black.
Habitat & Behavior:
The Megapodiidae
are part of a family within the order Galliformes (chicken-like
birds) found only in the Australasian region. The family is comprised
of seven genera found in Australasia (Australia, New Guinea and
surrounding islands, eastern Indonesia, the Nicobar Islands, the
Philippines, Micronesia, Vanuatu, and Niuafo`ou of the Tonga Islands).
The Micronesian Megapode is generally a bird of the forest.
Megapodes are sometimes called “incubator birds” because
they rely on solar energy, volcanic activity, or microbial decomposition
as a heat source for incubation. They are also characterized by
laying large eggs without an air chamber. Chicks lack an egg tooth
at hatching and kick their way out of the egg. Megapode chicks are
precocial (feathered, able to walk, and able to regulate their body
temperature) at hatching and the adults do not care for the young.
The Micronesian Megapode seems to be an omnivore, taking a variety
of plant and animal foods available on the forest floor, including
seeds, beetles, ants, other insects, and plant matter.
Micronesian megapodes are known to give at least three types of
calls, including two calls that are different for males and females
and that may be given in a duet. Duetting in birds is correlated
with year-round territorial behavior and life-long pair bonds.
Past & Present:
The Micronesian Megapode was historically widespread
throughout the Mariana Island chain but declined on all of the southern
Mariana Islands (Guam, Rota, Aguiguan, Tinian, and Saipan) in the
19th and early 20th centuries. While the megapode was extirpated
on Guam and Rota, small, remnant populations persist on Aguiguan
and Tinian, along with a very small (possibly reintroduced) population
on Saipan.
The megapode remains in relatively large numbers only on the smaller,
mostly uninhabited northern islands of Anatahan, Sarigan, Guguan,
Pagan, Maug, Alamagan, Ascuncion, and possibly Agrihan. Population
estimates of the megapode total about 1,440 to 1,975 birds in the
island chain.
The decline in numbers is thought to be a result of exploitation
and habitat loss. Overgrazing by feral goats, cattle, and pigs has
had a profound effect on the vegetation of the islands. In addition
to possible direct human predation, megapodes are known to be preyed
on by introduced monitor lizards and may also be preyed on by feral
dogs, cats, and pigs.
A serious potential threat to megapode populations is the establishment
of the brown tree snake from Guam to other islands in the Marianas
archipelago. The brown tree snake was accidentally introduced to
Guam shortly after World War II and has systematically spread throughout
the island, causing the loss of nearly all of the avifauna (birds)
and some of the other native vertebrate and invertebrate species
of Guam.
Conservation Efforts:
The U.S. Fish and Wildlife Service (Service)
listed the Micronesian Megapode as endangered in 1970. In 1982,
the Service conducted the Micronesian Forest Bird Surveys in the
Marianas and determined the status of populations in the southern
Marianas. More recent surveys have been completed for the islands
of Rota, Tinian, Saipan, and Sarigan. In addition, the Service is
currently negotiating a Habitat Conservation Plan with the Commonwealth
of the Northern Marianas Islands (CNMI) for the island of Rota.
This could potentially benefit the megapode should it ever be reintroduced
onto Rota.
Various other U.S. government agencies such as the U.S. Department
of Agriculture’s Wildlife Services and the military have heightened
awareness of the serious threat of the brown tree snake and work
together to reduce the likelihood of transporting snakes in equipment
shipments.
The CNMI government declared the islands of Guguan, Asuncion, Maug,
and Uracas wildlife sanctuaries in the early 1980s, providing protected
habitat for the megapode and other wildlife.
Trivia quiz:
Megapodes are sometimes called “incubator
birds” because they:
[a] rely
on solar energy, volcanic activity, or microbial decomposition for
incubation
[b] sit on
their eggs longer than any other forest bird
[c] sit on
their eggs like chickens
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