Wednesday, December 5, 2012

The Philippine Eagle

The Philippine Eagle (Pithecophaga jefferyi), also known as the Monkey-eating Eagle, and is endemic to forests in the Philippines. It has brown and white-coloured plumage, and a shaggy crest, and generally measures 86 to 102 cm in length and weighs 4.7 to 8 kilograms. It is considered the largest of the extant eagles in the world in terms of length, with the Steller's Sea Eagle and the Harpy Eagle being larger in terms of weight and bulk. Among the rarest and most powerful birds in the world, it has been declared the Philippine national bird.

The male and female Philippine eagle is similar in appearance, possessing a creamy white belly and under wing, whilst the upper parts are a rich chocolate-brown, with a paler edge. The long feathers of the head and nape form a distinctive, shaggy crest and are creamy-buff in colour with black streaks.

Did You Know
            A recent study of the Philippine Eagle's DNA suggests that the bird has a unique evolutionary history. Its genetic sequence differs from those of other large eagles. Researchers from the University of Michigan analysed the DNA isolated from blood samples of the Philippine Eagle. The sequence was then compared to those of the Harpy Eagle, Crested Eagle, and the New Guinea Harpy Eagle. All three are related genetically but they are not closely related to the Philippine Eagle. These species were once believed to be closely related due to their similar sizes, habitat, and habits; however, these similarities are now believed to be the result of convergent evolution. It is actually believed that the closest relative to the Philippine Eagle may be the much smaller snake eagles.

Scientific Classification


Other Names

Monkey Eating Eagle
Aguila Comemonos

            The Philippine eagle is classified as Critically Endangered (CR) on the IUCN Red List, and listed on Appendix I of CITES


            During the most recent population survey (2006) the expected population 350 - 670 birds including young ones.

This eagle is found in dipterocarp and mid-montane forests, particularly in steep areas. Its elevation ranges from the lowlands to mountains of over 1,800 metres. It is estimated that only 9,220 square kilometres of old growth forest remains in the bird's range. However, its total estimated range is about 146,000 square kilometers.

            The Philippine Eagle is endemic to the Philippines and can be found on four major islands: eastern Luzon, Samar, Leyte and Mindanao. The largest number of eagles resides on Mindanao, with between 82 and 233 breeding pairs. Only six pairs are found on Samar, two on Leyte, and a few on Luzon. It can be found in Northern Sierra Madre National Park on Luzon and Mount Apo and Mount Kitanglad National Parks on Mindanao.

            The Philippine Eagle was known initially as the Philippine Monkey-Eating Eagle because it was believed to feed on monkeys (the only monkey native to the Philippines is the Philippine long-tailed macaque) almost exclusively; this has proven to be inaccurate. This may be due in part to the fact that the first examined specimen was found to have undigested pieces of a monkey in its stomach. Like most predators, the Philippine Eagle is an opportunist that takes prey based on its local level of abundance and ease. The Philippine Eagle is apex predator in its range. Prey specimens found at the eagle's nest have ranged in size from a small bat weighing 10 g to a Philippine deer weighing 14 kg.

            The species' flight is fast and agile, resembling the smaller hawks more than similar large birds of prey. Juveniles in play behaviour have been observed gripping knotholes in trees with their talons and, using its tail and wings for balance, inserting its head into a tree cavity. Additionally, they have been known to attack inanimate objects for practice as well as attempt to hang upside down to work on their balance. As the parents are not nearby when this occurs, it has been suggested that they do not play a role in teaching the juvenile to hunt. Life expectancy for a wild eagle is estimated to be anywhere from 30 to 60 years. A captive Philippine Eagle lived for 41 years in Rome Zoo, and it was already adult when it arrived at the zoo. However, it is believed that wild birds on average live shorter lives than captive birds.

            The female matures sexually at five years of age and the male at seven. Like most eagles, the Philippine Eagle is monogamous. Once paired, a couple remains together for the rest of their lives. If one dies, the remaining eagle often searches for a new mate to replace the one lost. The female typically lays one egg in the late afternoon or at dusk, although occasionally two have been reported. If an egg fails to hatch or the chick dies early, the parents will likely lay another egg the following year. Copulation may last a few days after the egg is laid to enable another egg to be laid should the first one fail. The egg is incubated for 58 to 68 days (typically 62 days) after being laid. Both sexes participate in the incubation, but the female does the majority of incubating during the day and all of it at night. Both sexes help feed the newly hatched eaglet. Additionally, the parents have been observed taking turns shielding the eaglet from the sun and rain until it is seven weeks old.

Forest destruction and fragmentation, through commercial timber extraction and shifting cultivation, is the principal long-term threat. Old-growth forest continues to be lost rapidly, such that as little as 9,220 kmsq may remain within the eagle's range. Moreover, most remaining lowland forest is leased to logging concessions. Mining applications pose an additional threat. Uncontrolled hunting (for food and, at least formerly, zoo exhibits and trade) is perhaps the most significant threat in the short term. Naive juvenile birds are easily shot or trapped, as are adults nesting near forest edges. Birds are also vulnerable to accidental capture in traps intended for wild pigs and deer, and there are several records of individuals caught in snares presumably whilst hunting on the forest floor. Pesticide accumulation is another potential but unproven threat which may reduce its already slow reproductive output.

Conservation Measures
            The Philippine eagle is protected by law in the Philippines and occurs in a number of protected areas; international trade and movement of this species is also restricted and controlled by CITES (the Convention on International Trade in Endangered Species). The Philippine Eagle Conservation Programme is working on educational campaigns, protecting and monitoring nests and a conservation breeding scheme; so far, two captive-bred chicks have been produced with the aim of reintroducing them to the wild. In addition, chicks and eggs have been taken from areas of habitat at risk in order to establish a viable captive population from which individuals can be reintroduced to the wild. Despite these efforts, however, should habitat loss and subsequent human settlement continue at the current rate it seems doubtful that this majestic species will ever recover.


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