Eagles have held a special place in the cultures of many civilizations because of their impressive size and beauty. Used to symbolize royal power, from ancient Egypt to the Roman and Napoleonic empires, eagles have appeared on coins, standards, and weaponry.
Species Description and Range
The Philippine monkey-eating eagle is well named for its preference for eating monkeys, particularly macaques.
This ferocious-looking bird stands over 3 feet (1 m) tall and can weigh up to 9 pounds (4 kg) -- larger than a golden eagle. Bluish eyes, a large, sharp, curved beak, and a warlike headdress of spiky feathers, give the Philippine eagle a striking appearance.
First described in 1894 in the Philippines, the total wild population of the Philippine eagle is now estimated to be under 200. Once found in thick, mountainous forests on most of the larger Philippine islands, the eagle has been extirpated from several islands just in the last 20 years (see also Spotlight on Island Biogeography).
Philippine eagles are raptors, the group of birds also called "birds of prey" that includes hawks, falcons, eagles, owls, and vultures. Raptors are excellent hunters. They seize their prey (small mammals, fish, and other birds) with their taloned feet and tear the meat with sharp, hooked beaks.
Philippine eagles inhabit tropical rain forests and are well-adapted to life in dense foliage. Despite their great size, they have short, broad wings and a squared-off tail that allows them to rise almost vertically between trees and maneuver with speed and agility through branches and vines. They are adept at snatching monkeys or other mammals or birds from trees.
The Philippine eagle also attacks domestic animals such as dogs, pigs, and young goats.
Like most big predators, the Philippine eagle requires a large territory for hunting. Philippine eagles also require the tallest trees, those which emerge above the rain forest canopy, for nesting. They have a very low reproduction rate, laying just one or two eggs each year.
Causes of Endangerment
Raptors are threatened worldwide. Historically, raptors have been persecuted simply because of their predatory nature. Humans kill them to protect domestic animals, or to eliminate competition for a sought-after prey species.
The Philippine eagle also was a prized trophy for hunters. Once firearms became widely available in the Philippines after World War I, the number of eagles killed for sport sky-rocketed.
Even legal protection was of no use for quite awhile. When important people paid large sums of money to hunt the eagles, often it was the game wardens who led them to the birds!
Because of their position at top of the food chain, raptors are particularly vulnerable to toxins, such as pesticides, which build up in their prey species. Peregrine falcons and bald eagles in North America were nearly eliminated by the widespread use of the pesticide DDT.
Tropical forest raptors like the Philippine eagle have been greatly impacted by habitat destruction. Reduced territory size, declining numbers of prey animals, and disappearance of large nesting trees all have contributed to the eagle's decline. It is estimated that 80 percent of Philippine rain forests have disappeared since the 1970s.
The Philippine eagle became a desirable acquisition for zoos and private collectors, beginning in the 1960s. Collectors stole young eagles from nests for sale to the highest bidder.
Hunting of and trade in the Philippine eagle are now prohibited. The greatest threat to its survival remains the continued loss of its tropical rain forest habitat. At a minimum, selective logging methods should be employed to protect the large nesting trees and leave sufficient tracts of undisturbed forest to support eagles.
In addition, the use of agricultural pesticides needs to be reduced to prevent poisoning of animals at the top of food chains (see Spotlight on the Bald Eagle).
Question for Thought
Eagles are particularly sensitive to pollution because of their position at the top of the food chain. What other endangered animals have this same characteristic?
Vultures are another bird of prey that have a bad reputation, but they play an important role in the ecosystem. What can be done to change people's perception of raptors as evil or dangerous? How can we promote understanding of raptors' role in ecosystems?
Activities: [CS1-1,CS2-2,CS2-7, General]
Words in bold italics can be found in the glossary.