The Harpy Eagle (Harpia harpyja), sometimes known as the American Harpy Eagle, is a Neotropical species of eagle. It is the largest and most powerful raptor found in the Americas, and among the largest extant species of eagles in the world. It usually inhabits tropical lowland rainforests in the upper (emergent) canopy layer. Destruction of its natural habitat has seen it vanish from many parts of its former range, and it is almost extinct in Central America.
The Harpy Eagle was first described by Linnaeus in his Systema Naturae in 1758 as Vultur harpyja, after the mythological beast harpy. The only member of the genus Harpia, the Harpy Eagle is most closely related to the Crested Eagle (Morphnus guianensis) and the New Guinea Harpy Eagle (Harpyopsis novaeguineae), the three composing the subfamily Harpiinae within the large family Accipitridae. Previously thought to be related, the Philippine Eagle has been shown by analysis of DNA to belong elsewhere in the raptor family as it is related to the Circaetinae.
The upper side of the Harpy Eagle is covered with slate black feathers, and the underside is mostly white, except for the feathered tarsi, which are striped black. There is a black band across the chest up to the neck. The head is pale grey, and is crowned with a double crest. The plumage of male and female is identical. The tarsus is up to 13 cm (5.1 in) long.
Female Harpy Eagles typically weigh 6 to 9 kg (13 to 20 lb). One exceptionally large captive female, "Jezebel", weighed 12.3 kg (27 lb). Being captive, this large female may not be representative of the weight possible in wild Harpy Eagles due to differences in the food availability. The male, in comparison , is much smaller and weighs only about 4 to 4.8 kg (8.8 to 11 lb). Harpy Eagles are 89–105 cm (2.92–3.44 ft) long and have a wingspan of 176 to 201 cm (5 ft 9 in to 6 ft 7 in). Among the standard measurements, the wing chord measures 54–63 cm (1 ft 9 in–2 ft 0.8 in), the tail measures 37–42 cm (1 ft 3 in–1 ft 5 in), the tarsus is 11.4–13 cm (4.5–5.1 in) long and the bill (from the gape) is 6.5 cm (2.6 in). It is sometimes cited as the largest eagle, however the Philippine Eagle is somewhat longer on average and the Steller's Sea Eagle is slightly heavier on average. The wingspan of the Harpy Eagle is relatively small, an adaptation that increases maneuverability in forested habitats and is shared by other raptors in similar habitats. The wingspan of the Harpy Eagle is surpassed by several large eagles who live in more open habitats, such as those in the Haliaeetus and Aquila genera. The extinct Haast's Eagle was significantly larger than all extant eagles, including the Harpy.
Distribution and habitat
Rare throughout its range, the Harpy Eagle is found from Mexico, through Central America and into South America to Argentina. In Central America the species is almost extinct, subsequent to the loss of much of the rainforest there. In rainforests, they live from the canopy to the emergent. Within the rainforest, they hunt in the canopy or sometimes on the ground, and perch on emergent trees looking for prey.
The Harpy Eagle is an actively hunting carnivore and is an apex predator, meaning that adults are at the top of a food chain and have no natural predators. Its main prey are tree-dwelling mammals and a majority of the diet has been shown to focus on sloths and monkeys. Research conducted by Aguiar-Silva between 2003 and 2005 in a nesting site in Parintins, Amazonas, Brazil, collected remains from prey offered to the nestling and after sorting them, concluded that, in terms of individuals preyed upon, the harpy's prey basis was composed in 79% by sloths from two species: Bradypus variegatus amounting to 39% of the individual prey base, and Choloepus didactylus to 40%; various monkeys amounted to 11.6% of the same prey base. In a similar research venture in Panama, where a couple of captive-bred subadults was released, 52% of the male's captures and 54% of the female's were of two sloth species (Bradypus variegatus and Choloepus hoffmanni). At one Venezuelan nest, all remains found around the nest site were comprised by sloths. Monkeys regularly taken can include capuchin monkeys, saki monkeys, howler monkeys and spider monkeys. Other partially arboreal mammals are also predated given the opportunity, including porcupines, squirrels, opossums, anteaters, and even relatively large carnivores such as kinkajous, coatis and tayras. In the Pantanal, a pair of nesting eagles preyed largely on the porcupine Coendou prehensilis and on the agouti Dasyprocta azarae. The eagle may also attack bird species such as macaws: At the Parintins research site, the Red-and-green Macaw made up for 0.4% of the prey base, with other birds amounting to 4.6%. Other parrots have also been predated, as well as cracids such as curassows and seriemas. Additional prey items reported include reptiles such as iguanas, tejus and snakes. Snakes of up to 5 cm (2.0 in) in diameter have been observed to be cut in half, then the pieces are swallowed whole. On occasion, larger prey such as capybaras, peccaries and young deer are taken and they are usually taken to a stump or low branch and partially eaten, since they are too heavy to be carried whole to the nest. The Harpy have been recorded as taking domestic livestock, including chickens, lambs, goats and young pigs, but this is extremely rare under normal circumstances. They control population of mesopredators such as capuchin monkeys which prey extensively on bird's eggs and which (if not naturally controlled) may cause local extinctions of sensitive species.
The Harpy's talons are extremely powerful and assist with suppressing prey. The Harpy Eagle can exert a pressure of 42 kgf/cm² (4.1 MPa or 530 lbf/in2 or 400 N/cm2) with its talons. The Harpy Eagle has been recorded as lifting prey up to equal their own body weight. That allows the bird to snatch a live sloth from tree branches, as well as other huge prey items. Males have been shown to focus on relatively smaller prey, with a typical range of 0.5 to 2.5 kg (1.1 to 5.5 lb) or about half their own weight. The larger females almost invariably take larger prey, with a minimum prey weight of around 2.7 kg (6.0 lb). Adult female Harpys can grab a large male howler or spider monkey or mature sloth weighing 6 to 9 kg (13 to 20 lb) while in flight and fly off without needing to land, a feat of enormous strength. Prey items taken to the nest are normally medium-sized, having been recorded from 1 to 4 kg (2.2 to 8.8 lb).
Sometimes, Harpy Eagles will still-hunt, a common hunting strategy in other forest-dwelling raptors. In Harpys, this consists of looking and listening for long periods of time from a high perch near an opening, a river or salt-lick (where many mammals go to feed for nutrients). The more common hunting technique of the species is perch-hunting, which consists of scanning around for prey activity while briefly perched between short flights from tree to tree. When prey is spotted, a fast swoop or snatch occurs, after which the talons often kill the prey in seconds. On occasion, Harpy Eagles may also hunt by flying adjacent to or right over the canopy. Apparently, they've also been observed tail-chasing, a predation style common to the bird-hunting Accipiter hawks. While tail-chasing, they pursue a bird closely in flight while twisting between trees, vines and branches, a skill that requires both considerable speed and great agility.
A pair of Harpy Eagles lays two white eggs in a large stick nest high in a tree, and raise one chick every 2–3 years. After the first chick hatches, the second egg is ignored and fails to hatch. The chick fledges in 6 months, but the parents continue to feed it for another 6 to 10 months. It can be aggressive toward humans who disturb its nesting sites or appear to be a threat to its young. The harpy often builds its nest in the crown of the kapok tree, one of the tallest trees in South America. In many South American cultures it is considered bad luck to cut down the kapok tree, which may help safeguard the habitat of this stately eagle. The bird also uses other huge trees to build its nest on, such as the Brazil nut tree. A nesting site found in the Brazilian Pantanal was built on a Cambará tree (Vochysia divergens).
Status and conservation
The Harpy Eagle is threatened primarily by habitat loss provoked by the expansion of logging, cattle ranching, agriculture and prospecting; secondarily by being hunted as an actual threat to livestock and/or a supposed one to human life, due to its great size. Such threats apply throughout its range, in large parts of which the bird has become a transient sight only: in Brazil, it was all but totally wiped out from the Atlantic rainforest and is only found in numbers in the most remote parts of the Amazon Basin; a Brazilian journalistic account of the mid-1990s already complained that at the time it was only found in numbers, in Brazilian territory, on the northern side of the Equator. Scientific 1990s records, however, suggest that the Harpy Atlantic Forest population may be migratory. Subsequent research in Brazil has established that, as of 2009, the Harpy Eagle, outside the Brazilian Amazon, is critically endangered in Espírito Santo, São Paulo and Paraná, endangered in Rio de Janeiro, and probably extirpated in Rio Grande do Sul and Minas Gerais – the actual size of their total population in Brazil is unknown.
Globally, The Harpy Eagle is considered Near Threatened by IUCN and threatened with extinction by CITES (appendix I). The Peregrine Fund until recently considered it a "conservation-dependent species", meaning it depends on a dedicated effort for captive breeding and release to the wild as well as habitat protection in order to prevent it from reaching endangered status but now has accepted the Near Threatened status. The Harpy Eagle is considered critically endangered in Mexico and Central America, where it has been extirpated in most of its former range: in Mexico, it used to be found as far North as Veracruz, but today probably occurs only in Chiapas in the Selva Zoque. It is considered as Near Threatened or Vulnerable in most of the South American portion of its range: at the Southern extreme of its range, in Argentina, it's found only in the Parana Valley forests at the province of Misiones. It has disappeared from El Salvador, and almost so from Costa Rica.
Various initiatives for restoration of the species are currently afoot in various countries: Since 2002, Peregrine Fund initiated a conservation and research program for the Harpy Eagle in the Darién Province, Panama. A similar—and grander, given the dimensions of the countries involved—research project is currently occurring in Brazil, at the National Institute of Amazonian Research, through which 45 known nesting locations (presently updated to 62, only three outside the Amazonian Basin and all three presently inactive) are being monitored by researchers and volunteers from local communities. A Harpy Eagle chick has been fitted with a radio transmitter that allows it to be tracked for more than three years via a satellite signal sent to INPE (Brazilian National Institute for Space Research). Also, a photographic recording of a nest site in the Carajás National Forest is presently being made by the photographer for the Brazilian edition of National Geographic Magazine João Marcos Rosa.
In Belize, there exists The Belize Harpy Eagle Restoration Project. It began in 2003 with the collaboration of Sharon Matola, Founder & Director of The Belize Zoo and The Peregrine Fund. The goal of this project was the reestablishment of the Harpy Eagle within Belize. The population of the eagle declined as a result of forest fragmentation, shooting, and nest destruction, resulting in near extirpation of the species. Captive bred Harpy Eagles were released in the Rio Bravo Conservation and Management Area in Belize, chosen for its quality forest habitat and linkages with Guatemala and Mexico. Habitat linkage with Guatemala and Mexico were important for conservation of quality habitat and the Harpy Eagle on a regional level. As of November 2009, fourteen Harpy Eagles have been released and are monitored by the Peregrine Fund, through satellite telemetry.
In January 2009, a chick from the all but extirpated population in the Brazilian state of Paraná was hatched in captivity at the preserve kept at the vicinity of the Itaipu dam by the Brazilian/Paraguayan state-owned company Itaipu Binacional. In September 2009, an adult female, after being kept captive for twelve years in a private reservation, was fitted with a radiotransmitter before being restored to the wild in the vicinity of the Pau Brasil National Park (formerly Monte Pascoal NP), in the State of Bahia.
In December 2009, a 15th Harpy Eagle was released into the Rio Bravo Conservation and Management Area in Belize. The release was set to tie in with the United Nations Climate Change Conference 2009, in Copenhagen. The 15th eagle, nicknamed "Hope," by the Peregrine officials in Panama, was the "poster child" for forest conservation in Belize, a developing country, and the importance of these activities in relation to Global Warming and Climate Change. The event received coverage from Belize's major media entities, and was supported and attended by the U.S. Ambassador to Belize, Vinai Thummalapally, and British High Commissioner to Belize, Pat Ashworth. 
In Colombia, as of 2007, a couple of Harpies composed of an adult male and a subadult female confiscated from wildlife trafficking were restored to the wild and monitored in Paramillo National Park in Córdoba, another couple being kept in captivity at a research center for breeding and eventual release. A monitoring effort with the help of volunteers from local Native American communities is also afoot in Ecuador, including the joint sponsorship of various Spanish universities—this effort being similar to another one going on since 1996 in Peru, centered around a Native Community in the Tambopata Province, Madre de Dios Region. Another monitoring project, begun in 1992, was operating as of 2005 in the state of Bolívar, Venezuela.
- The Harpy Eagle is the national bird of Panama and is depicted on the coat of arms of Panama.
- The Harpy Eagle is featured on the cover of the O'Reilly Media book, R in a Nutshell.
- The Harpy Eagle was the inspiration behind the design of Fawkes the Phoenix in the Harry Potter film series.
- A Harpy Eagle called Bubba features extensively in Garry Kilworth's novel "Frost Dancers" as the adversary of the hares that are the heroes of the book.
- The 15th Harpy Eagle, named "Hope" released in Belize, was dubbed, "Ambassador for Climate Change," in Belize, in light of the United Nations Climate Change Conference 2009
- BirdLife International (2008). Harpia harpyja. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 January 2009.
- (Latin) Linnaeus, C (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.. Holmiae. (Laurentii Salvii).. p. 86. "V. occipite subcristato."
- Lerner, H. R. L.; Mindell, D. P. (2005). "Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA". Molecular Phylogenetics and Evolution 37 (2): 327–346. DOI:10.1016/j.ympev.2005.04.010. ISSN 1055-7903. PMID 15925523. http://www-personal.umich.edu/~hlerner/LM2005.pdf. Retrieved 31 May 2011.
- Ferguson-Lees, J.; Christie, D. (2001). Raptors of the World. London: Christopher Helm. pp. 717–19. ISBN 0-7136-8026-1.
- Thiollay, J. M. (1994). Harpy Eagle (Harpia harpyja). p. 191 in: del Hoy, J, A. Elliott, & J. Sargatal, eds. (1994). Handbook of the Birds of the World. Vol. 2. New World Vultures to Guineafowl. Lynx Edicions, Barcelona. ISBN 84-87334-15-6
- Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0-85112-235-9.
- O'Connor, R. J. (1984). The Growth and Development of Birds. ISBN 0-471-90345-0
- Arent, L. A. (2007). Raptors in Captivity. Hancock House, Washington. ISBN 978-0-88839-613-6
- Museum of New Zealand (1998). Giant eagle (Aquila moorei), Haast’s eagle, or Pouakai. Accessed 4 June 2011
- Weidensaul, Scott (2004). The Raptor Almanac: A Comprehensive Guide to Eagles, Hawks, Falcons, and Vultures. New York, New York: Lyons Press. pp. 280–81. ISBN 1-58574-170-1.
- Touchton, Janeene M.; Yu-Cheng Hsu; Palleroni, Alberto (2002). "Foraging ecology of reintroduced captive-bred subadult harpy eagles (Harpia harpiya) on Barro Colorado Island, Panama". Ornitologia Neotropical (The Neotropical Ornithological Society) 13. http://www.fondoperegrino.org/Touchton-Harpy.pdf.
- "Aguiar-Silva 2007 Dieta do gavião-real Harpia harpyja (Aves: Accipitridae) em florestas de terra firme de Parintins, Amazonas, Brasil", abstract available at 
- "Giant Harpy Eagle grabs the Sloth Video". Disclose.tv. http://www.disclose.tv/action/viewvideo/9911/Giant_Harpy_Eagle_grabs_the_Sloth/. Retrieved 2009-01-12.
- "Gavião-real" (in Portuguese). Brasil 500 Pássaros. Eletronorte. http://webserver.eln.gov.br/Pass500/BIRDS/1birds/p52.htm. Retrieved July 6, 2010.
- Adam Vaughan (July 6, 2010"Monkey-eating eagle divebombs BBC filmmaker as he fits nest-cam". guardian.co.uk. http://www.guardian.co.uk/environment/2010/jul/06/harpy-eagle-attack-cameraman.).
- Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
- Cf. Brazilian birdwatchers' (Wikiaves) site, [unreliable source?]
- Cf. Aves de Rapina do Brasil site
- Talia Salanotti, researcher for the Brazilian National Institute of Amazonian Research, cf. O Globo, May the 13th. 2009; abridgement available at ; on the random killing of harpies in frontier regions, see 
- "Senhora dos ares", Globo Rural, ISSN 0102-6178, 11:129, July 1996, pgs. 40 and 42
- Cf. Birdlife International
- Where an adult male was observed in August 2005 at the preserve kept by mining corporation Vale do Rio Doce at Linhares: cf. 
- Neverthless, in 2006, an adult female – probably during migration – was seem and photographed at the vicinity of Tapira, in the Minas Gerais cerrado: cf. 
- "Viva a Rainha", story by Clarice Couto, Globo Rural, 25:288, October 2009, page 65
- For a map of the species historical and current range, see Heather R. L. Lerner, Jeff A. Johnson, Alec R. Lindsay, Lloyd F. Kiff and David P. Mindell: "It's not too Late for the Harpy Eagle (Harpia harpyja): High Levels Of Genetic Diversity and Differentiation Can Fuel Conservation Programs", Figure 1, available at 
- Cf. Peregrine Fund website
- Projecto Gavião-real Inpa; Globo Rural, 25:288, page 62
- Cf. blog
- Revista Globo Rural, 24:287, September 2009, 20
- "The Importance of Hope, the Harpy Eagle". 7 News Belize. 14 December 2009. http://www.7newsbelize.com/sstory.php?nid=15760&frmsrch=1.
- Cf. 
- Renzo Piana, "The Harpy Eagle (Harpia harpyja) in the Infierno Native Community", available at