Philippine Eagle: The Bird That Lays 1 Egg Every 2 Years

The Philippine eagle (Pithecophaga jefferyi), also known as the great Philippine eagle or monkey-eating eagle, is one of the largest eagles in the world and the national bird of the Philippines.

Philippine eagles have a wingspan of 6.5 feet (1.9 meters) and weigh 10 to 18 pounds (4.5 to 8.1 kilograms), making them similar in size to the Harpy eagle and Steller's sea eagle.

These huge birds have dark brown wing feathers edged with white and white undersides. They communicate with high-pitched whistles; captive Philippine eagles can live up to 40 years.

Philippine Eagle Family Life

Philippine eagles live in pairs, and a Philippine eagle pair will bond for life. Females lay one egg every two years, and the Philippine eagle parents take turns incubating the egg.

The female stays in the nest for the first 40 days of the eaglet's life while the male hunts. The young chick will live with its parents for about a year and a half before leaving its parents' territory to find a suitable habitat to form a new breeding pair.

Where Do Philippine Eagles Live?

Philippine eagles occur in old-growth forest on just four islands in the Philippines: Luzon, Samar, Leyte and Mindanao. Most of the population lives in Mindanao.

Unfortunately, the lowland and montane forests where Philippine eagles live are shrinking due to deforestation.

The moniker "monkey-eating eagle" gives an indication as to the Philippine eagle diet. But they don't just eat monkeys — these opportunistic raptors eat a wide variety of species depending on what's available in their habitat.

For example, these apex predators' primary prey species on the island of Mindanao is the Philippine flying lemur, and they're known to eat macaques. But Philippine eagles also eat bats, cloud rats, monitor lizards, other birds, palm civets and snakes.

To take down larger prey, Philippine eagle pairs will sometimes hunt together. One bird will distract the prey while the other goes in for the kill.

The International Union of Conservation of Nature declared the Philippine eagle critically endangered in 1994. Destruction of its forest habitat is the biggest threat to Philippine eagles. Habitat loss poses several problems.

Philippine eagle pairs make their nests in large dipterocarp trees; if a tree with a nest is cut down, any chicks or eggs in the nest will die, which is a big deal for a species that only lays a single egg every few years.

Deforestation also leads to habitat fragmentation. This means that a new breeding pair may have to look far to find their own territory and puts Philippine eagles in closer contact with local communities, which brings its own dangers.

According to the Philippine Eagle Foundation, which leads conservation efforts, including running captive breeding programs, at least one Philippine eagle a year dies due to hunting by humans.

"The world might lose this majestic eagle within this lifetime if we don’t act fast to save it” Dennis Salvador, Executive Director of the Philippine Eagle Foundation, in a press release.

How Many Philippine Eagles Are Left?

A 2023 study published in the journal "Animal Conservation" estimated there are 392 breeding pairs, or 784 mature individuals, left in the wild. The population has experienced a slight increase due to conservation efforts but remains critically endangered.