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Pithecophaga jefferyigreat Philippine eagle(Also: Philippine eagle)

By Flora Sison

Geographic Range

Pithecophaga jefferyi is endemic to the Philippines and is found on parts of the larger islands of Luzon, Samar, Leyte, and Mindanao. (Bueser, et al., 2003; Delacour and Mayr, 1946; Ibanez, et al., 2003)

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. ("Philippine Eagle - Pithecophaga jefferyi - ARKive", 2004; "Philippine Eagle Foundation", 2004; Bueser, et al., 2003; Ibanez, et al., 2003)

  • Range elevation
    150 to 1450 m
    492.13 to 4757.22 ft

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. ("Philippine Eagle - Pithecophaga jefferyi - ARKive", 2004; "Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Delacour and Mayr, 1946)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    6500 g
    229.07 oz
  • Average mass
    6500 g
    229.07 oz
    AnAge
  • Range length
    90 to 100 cm
    35.43 to 39.37 in
  • Average wingspan
    2 m
    6.56 ft

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. ("Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Bueser, et al., 2003; Ibanez, et al., 2003; "Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Bueser, et al., 2003; Ibanez, et al., 2003)

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. ("Philippine Eagle - Pithecophaga jefferyi - ARKive", 2004; "Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Ibanez, et al., 2003)

  • Breeding interval
    Pithecophaga jefferyi breed once every two years.
  • Breeding season
    Pithecophaga jefferyi mate from October to December.
  • Range eggs per season
    1 to 2
  • Average eggs per season
    1
  • Average eggs per season
    1
    AnAge
  • Average time to hatching
    60 days
  • Average time to hatching
    63 days
    AnAge
  • Range fledging age
    7 to 8 weeks
  • Average fledging age
    7 weeks
  • Average time to independence
    5 months
  • Range age at sexual or reproductive maturity (female)
    3 to 5 years
  • Average age at sexual or reproductive maturity (female)
    5 years
  • Range age at sexual or reproductive maturity (male)
    4 to 7 years
  • Average age at sexual or reproductive maturity (male)
    7 years

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. ("Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Ibanez, et al., 2003)

  • Parental Investment
  • 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. ("Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003)

  • Range lifespan
    Status: captivity
    41 (high) years
  • Typical lifespan
    Status: wild
    30 to 60 years
  • Average lifespan
    Status: wild
    40 years
  • Average lifespan
    Status: captivity
    41 years
    AnAge

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. (Delacour and Mayr, 1946)

  • Range territory size
    60 to 130 km^2
  • Average territory size
    100 km^2

Home Range

A pair of Philippine eagles have a territory of 60 to 130 square kilometers. ("Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Bueser, et al., 2003)

Communication and Perception

Philippine eagles use vocalizations to call their mate and during mating seasons. Fledglings and parents communicate primarily through vocalizations. (Ibanez, et al., 2003)

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. ("Philippine Eagle - Pithecophaga jefferyi - ARKive", 2004; "Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Bueser, et al., 2003; Ibanez, et al., 2003)

  • Primary Diet
  • 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. ("Philippine Eagle Foundation", 2004)

  • Known Predators
    • Humans (Homo Sapien)

Ecosystem Roles

Philippine eagles are top predators in the ecosystems they inhabit. ("Philippine Eagle Foundation", 2004)

Economic Importance for Humans: Positive

Philippine eagles are hunted by humans for their feathers and as trophies. ("Philippine Eagle Foundation", 2004)

  • 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. ("Philippine Eagle Foundation", 2004; Ibanez, et al., 2003)

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. ("IUCN List of Threatened Species: Pithecophaga jefferyi", 2005; "Philippine Eagle - Pithecophaga jefferyi - ARKive", 2004; "Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003)

Other Comments

Pithecophaga jefferyi is the national bird of the Philippines. ("Philippine Eagle Foundation", 2004; "Species Info – Philippine Eagle. Red Book Data – Threatened Birds of Asia", 2003; Bueser, et al., 2003; Delacour and Mayr, 1946; Ibanez, et al., 2003)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

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

Glossary

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

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.

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.

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