Pithecophaga jefferyi

Geographic Range

Pithecophaga jefferyi is endemic to the Philippines and is found on parts of the larger islands of Luzon, Samar, Leyte, and Mindanao.

• Biogeographic Regions
• oriental oriental
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Philippine eagles inhabit remnant patches of primary dipterocarp forest, a family of resinous trees that are found in the Old World tropics. Pithecophaga jefferyi also occurs in second growth and gallery forest.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

Physical Description

Pithecophaga jefferyi is the world’s largest eagle species. Males and females are similar in appearance. They have a white belly and underwing, while the upperparts are a rich brown, with pale edged feathers. The long feathers of the head and nape form a distinctive crest and are dark-brown and cream on the margins. Chicks have white down, and juveniles are similar in appearance to adults but have white margins to the feathers on the back and upperwing. The heavy legs are yellow with large, powerful claws, and the large, high arched, deep bill is a bluish-grey. Philippine eagles can be distinguished from white-breasted sea eagles ( Haliaeetus leucogaster )in flight by their long tails and rounded wings.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Pithecophaga jefferyi mate for life. When the partner dies, it is not unusual for the eagle to find a new mate. Four behaviors are associated with aerial displays of courtship behavior: mutual soaring, dive chase, talon presentation, and territorial flights. Mutual soaring is a circular gliding pattern by both birds where the male usually soars higher than the female. Dive chases are a diagonal drop in altitude with the wings half folded onto the body, with the male trailing behind the female. Talon presentation is characterized by a quick expansion of the talons toward the back of the female. The female may present her talons by flipping over and extending her talons. This mutual talon presentation is also seen in other raptor species. Territorial flight behaviors are gliding flights with the male slightly above the leading female.

• Mating System
• monogamous monogamous

The natural breeding cycle requires two years. Successful partners have only one offspring every two years. The breeding season is from October to December in order for the chick to hatch during the dry season (February to May). The chick hatches after 60 days and becomes a fledging at 7 to 8 weeks. Independence is reached at 5 months. Females reach sexual maturity at 3 to 5 years and males reach maturity at 4 to 7 years.

The nest is normally located between 27 to 50 meters from the ground. Pairs build an enormous nest, anywhere from 1.2 x 1.2 m to 1.2 x 2.7 m, in the canopy of dipterocarp forests or on a large epiphytic fern. The nests are made out of decaying twigs and sticks piled on top of each other. The same nest is used from year to year.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Females incubate the egg for roughly two-thirds of the incubation time, males incubate the egg the remaining one-third. The chick is protected and fed by both of the parents for 7 to 8 weeks. The eaglet leaves the nest at 5 to 6 months.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifespan/Longevity

Pithecophaga jefferyi can live anywhere from 30 to 60 years. A captive Philippine eagle lived to 41 years old in a zoo in Rome.

Behavior

Pithecophaga jefferyi fly by flapping their wings and soar only occasionally. They are thought to be non-migratory and primarily solitary. Philippine eagles are active during the day.

• Key Behaviors
• flies
• diurnal diurnal
• motile motile
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

A pair of Philippine eagles have a territory of 60 to 130 square kilometers.

Communication and Perception

Philippine eagles use vocalizations to call their mate and during mating seasons. Fledglings and parents communicate primarily through vocalizations.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Food habits vary from island to island. Philippine eagles feed mainly on medium-sized mammals, such as flying lemurs, palm civets, flying squirrels, and monkeys, giving them their other common name: 'monkey-eating eagles'. Other prey includes rats, snakes, small deer, birds, and bats.

Individuals hunt starting from their nest at the top of a hill and slowly move downhill from perch to perch before flying back up the hill upon reaching the bottom. They use this technique to conserve energy because they are able to soar from perch to perch while looking out for prey. Pairs have been observed hunting together; one individual acts as a decoy, drawing the attention of a group of monkeys towards it while its partner captures a monkey from behind.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates

• Animal Foods
• birds
• mammals
• reptiles

Predation

Philippine eagles have no known natural predators, except for humans. From 1999 to 2000, 5 eagles have been shot in Mindanao. In the Sierra Madre of Luzon, 3 have been trapped from 2002 to 2003. From 1998 to 2002, 3 of 4 young eagles with transmitters on them were lost to hunting and trapping.

Ecosystem Roles

Philippine eagles are top predators in the ecosystems they inhabit.

Economic Importance for Humans: Positive

Philippine eagles are hunted by humans for their feathers and as trophies.

• Positive Impacts
• body parts are source of valuable material

Economic Importance for Humans: Negative

Philippine eagles may sometimes take domestic livestock, such as poultry and small pigs.

Conservation Status

Pithcophaga jefferyi is one of the three most endangered eagle species in the world. Although probably never abundant, populations Philippine eagles have undergone a sharp decline, primarily as the result of habitat destruction. Many tropical forests in the Philippines have been cleared for commercial development and cultivation for agriculture purposes. Mining activities and hunting pose further threats, and the accumulation of pesticides may be responsible for a reduction in reproductive rate. Low reproductive rates and slow maturation lead to low replacement rates of the eagles that are being hunted. 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. Pithecophaga jefferyi is protected by law in the Philippines. International trade and transport of the species is also restricted by CITES (the Convention on International Trade in Endangered Species). The Philippine Eagle Conservation Program is working on educational campaigns, protecting and monitoring nests, and a conservation breeding plan.

Other Comments

Pithecophaga jefferyi is the national bird of the Philippines.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Flora Sison (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.

References

Bueser, G., K. Bueser, D. Afan, D. Salvador, J. Grier, R. Kennedy, H. Miranda. 2003. Distribution and nesting density of the Philippine Eagle Pithecophaga jefferyi on Mindanao Island, Philippines: what do we know after 100 years?. Ibis , 145:1: 130.

Delacour, J., E. Mayr. 1946. Birds of the Philippines . New York: The MacMillan Company.

Ibanez, J., H. Miranda, G. Balaquit-Ibanez, D. Afan, R. Kennedy. 2003. Notes on the breeding behavior of a Philippine Eagle pair at Mount Sinaka, Central Mindanao. The Wilson Bulletin , 115: 330-336.

2005. "IUCN List of Threatened Species: Pithecophaga jefferyi" (On-line). Accessed November 19, 2005 at http://www.redlist.org/search/details.php?species=17408 .

2004. "Philippine Eagle - Pithecophaga jefferyi - ARKive" (On-line). Accessed November 19, 2005 at http://www.arkive.org/species/GES/birds/Pithecophaga_jefferyi/ .

2004. "Philippine Eagle Foundation" (On-line). Accessed November 17, 2005 at http://philippineeagle.org/ .

2003. "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia" (On-line). Accessed November 17, 2005 at http://www.rdb.or.id/view_html.php?id=79&op=pithjeff .