The Maleo is an endemic bird inhabiting the forested areas of Sulawesi Island. Belonging to the family Megapodiidae, it is recognized scientifically as Macrocephalon maleo. In its native habitat, the bird is known for its unusual nesting behavior.
Unincubated Eggs Due to Size
Unlike most bird species, the Maleo is never observed incubating its eggs. Females choose to bury their eggs in warm soil or sand. Their behavior is closely tied to the size of the egg produced by the female Maleo.
A single Maleo egg can weigh up to 240 grams, accounting for up to 16 percent of the female's total body weight. Consequently, the female's body is not suited to incubate its own eggs in a nest.
An adult Maleo weighs an average of 1.5 kilograms with a body length of approximately 55 centimeters. The plumage on its back and wings is purplish-black, while the area from its breast to belly is covered in pinkish feathers.
The bird rests on a pair of grey legs measuring 21 centimeters in length. The legs serve both for walking through forest terrain and for digging into sandy soil during the nesting period.
Atop its head sits a dark grey casque, also known as kapseti. The casque functions to regulate the bird's body temperature while digging in warm ground.
When preparing to lay eggs, the Maleo selects sandy areas heated by geothermal energy or exposed to direct sunlight. The bird pecks at the soil surface with its beak to gauge the warmth around the nesting site.
The depth and width of the nesting hole vary depending on the soil temperature. In cooler areas, the Maleo digs deeper, reaching depths of up to 100 centimeters. Egg hatching inside the burrow requires a ground temperature of around 34 degrees Celsius.
Independent Behavior of Maleo Chicks
The incubation period for Maleo eggs underground lasts between 60 and 80 days. The eggshell hatches deep within the soil where it was buried, and the newly hatched chick digs its way up to the surface on its own.
Unassisted by its parents, the chick's journey to the surface can take several hours. A newly hatched Maleo chick weighs between 80 and 110 grams, with fully developed feathers.
The wings of the chick measure approximately 11 centimeters in length, with fully formed flight feathers. With the developed wing feathers, the chick is capable of short flights just a few hours after emerging from the ground.
In addition to flying, the chick can immediately forage for food on its own in the forest. The instinctual independence without parental care from birth is known as a precocial trait.
Upon emerging from the ground, the young Maleo faces potential threats from natural predators. Monitor lizards, wild boars, and snakes frequently target the chicks before they can fly to safety.
Beyond natural predation, egg harvesting by local residents contributes to the decline of the Maleo population. Taking eggs from nesting sites reduces the bird's birth rate in the wild.
With an estimated population between 8,000 and 14,000 individuals, the International Union for Conservation of Nature classifies the Maleo as Critically Endangered. Domestically, the Indonesian government designated the species as protected under Government Regulation No. 7 of 1999.
In addition to its protected status, the Central Sulawesi Provincial Government adopted the Maleo as the official provincial mascot in 1990.
References:
Kumaji, S. S., Wantogia, M., Mohamad, N., SM, F., Yusuf, D., Baderan, D. W. K., … Dunggio, I. (2024). Spatial Study of Maleo Bird Habitat Area Change in Sulawesi. Jurnal Biologi Tropis, 24(2), 309–316. https://doi.org/10.29303/jbt.v24i2.6754
Lase, J. A., Rafian, T., & Bilyaro, W. (2024). Maleo genetic resources (Macrocephalon maleo): Populations, extinction threats, and conservation efforts. Wahana Peternakan, 8(1), 95–103. https://doi.org/10.37090/jwputb.v8i1.1297
