Harpy eagle

The harpy eagle (Harpia harpyja) is a large neotropical species of eagle. It is also called the American harpy eagle to distinguish it from the Papuan eagle, which is sometimes known as the New Guinea harpy eagle or Papuan harpy eagle. It is the largest bird of prey throughout its range, 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 caused it to vanish from many parts of its former range, and it is nearly extirpated from much of Central America. It is the only member of the genus Harpia, which, together with Harpyopsis, Macheiramphus and Morphnus, fo...

Relatively rare and elusive throughout its range, the harpy eagle is found from southern Mexico (incl. Chiapas, Oaxaca and the Yucatán states) and south through Central America, into South America to as far south as Argentina. They can still be seen by tourists and locals in Costa Rica and Panama. As their preferred habitat is rainforest, they nest and hunt predominantly in the emergent layer. The eagle is most common in Brazil, where it is found across the entire country. With the exception of some areas of the aforementioned Panama and Costa Rica, the species is nearly extinct in Central America, likely due to the logging industry's decimation of much of the Meso-American rainforests. Their habitat is expected to decline further due to climate change. The harpy eagle prefers tropical, lowland rainforests and may also choose to nest within such areas from the canopy to the emergent vegetation. They typically occur below an elevation of 900 m (3,000 ft), but have been recorded at elevations up to 2,000 m (6,560 ft). Within the forests, they hunt in the canopy or, rarely, on the ground, and perch on emergent trees to scout for prey. They do not generally occur in disturbed areas, avoiding humans whenever possible, but regularly visit semi-open forest and pasture mosaic, in hunting forays. Harpies, however, can be found flying over forest borders in a variety of habitats, such as cerrados, caatingas, buriti palm stands, cultivated fields, and cities. They have recently been found in areas where high-grade forestry is practiced.

Venezuela

Full grown harpy eagles are at the top of a food chain. They possess the largest talons of any living eagle and have been recorded as carrying prey weighing up to roughly half of their own body weight. This allows them to snatch from tree branches live sloths and other large prey items. Most commonly, harpy eagles use perch hunting, in which they scan for prey activity while briefly perched between short flights from tree to tree. Upon spotting prey, the eagle quickly dives and grabs it. Sometimes, harpy eagles are "sit-and-wait" predators (common in forest-dwelling raptors), perching for long periods on a high point near an opening, a river, or a salt lick, where many mammals go to attain nutrients. On occasion, they may also hunt by flying within or above the canopy. They have also been observed tail-chasing: pursuing another bird in flight, rapidly dodging among trees and branches, a predation style common to hawks (genus Accipiter) that hunt birds. A recent literature review and research using camera traps list a total of 116 prey species. Its main prey are tree-dwelling mammals, and a majority of the diet has been shown to focus on sloths. 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 by its parents. The researchers found that 79% of the harpy's prey was accounted for by sloths from two species: 39% brown-throated sloth (Bradypus variegatus), and 40% Linnaeus's two-toed sloth (Choloepus didactylus). Similar research in Panama, where two captive-bred subadults were released, found that 52% of the male's captures and 54% of the female's were of two sloth species: brown-throated sloth and Hoffmann's two-toed sloth (Choloepus hoffmanni). Harpy eagles are capable of hunting all size of sloths, including full-grown adult two-toed sloths weighing up to 9 kg (20 lb). Another major prey of harpy eagles is monkeys. At several nests in Guyana, monkeys made up about 37% of the prey remains found at the nests. Similarly, cebid monkeys made up 35% of the remains found at 10 nests in Amazonian Ecuador. Monkeys regularly taken include capuchin monkeys, woolly monkeys, saki monkeys, howler monkeys, titi monkeys, squirrel monkeys, and spider monkeys. Smaller monkeys, such as tamarins and marmosets, are, however, seemingly ignored as prey by this species. Small monkeys typically weighing between 1 and 4 kg (2.2 and 8.8 lb), such as Wedge-capped capuchin (Cebus olivaceus), tufted capuchin (Sapajus apella), and white-faced saki (Pithecia pithecia) are the most frequently taken. Larger howler monkeys are also taken, mainly Colombian red howler (Alouatta seniculus), but also Guyanan red howler (Alouatta macconnelli) and mantled howler (Alouatta palliata). These monkeys typically weigh between 4.4 to 8.6 kg (9.7 to 19.0 lb) and female harpy eagles can prey on all ages and sexes, while male harpy eagles tend to focus on juveniles. In one study, breeding harpy eagles hunted Yucatán black howler (Alouatta pigra), the largest howler monkey which can weigh between 6.4 and 11.3 kg (14 and 25 lb), although the ages of the monkeys taken by these eagles are unknown. Nevertheless, adults of other large monkeys can be taken by female harpy eagles, including gray woolly monkey (Lagothrix lagothricha cana) and Peruvian spider monkey (Ateles chamek), and red-faced spider monkey (Ateles paniscus) which can weigh around 5.8 to 9.4 kg (13 to 21 lb) and possibly exceeding 10 to 11 kg (22 to 24 lb) in large males. Other partially arboreal and even land mammals are also preyed on given the opportunity. In the Pantanal, a pair of nesting eagles preyed largely on the porcupine (Coendou prehensilis) and the agouti (Dasyprocta azarae). Both species of tamanduas (Tamandua mexicana & T. tetradactyla) are taken and armadillos, especially nine-banded armadillo (Dasypus novemcinctus) are also taken, as well as carnivores such as olingos (Barraricyon), kinkajous…

This species is largely silent away from the nest. There, the adults give a penetrating, weak, melancholy scream, with the incubating males' call described as "whispy screaming or wailing". The females' calls while incubating are similar, but are lower-pitched. While approaching the nest with food, the male calls out "rapid chirps, goose-like calls, and occasional sharp screams". Vocalization in both parents decreases as the nestlings age, while the nestlings become more vocal. The nestlings call chi-chi-chi...chi-chi-chi-chi, seemingly in alarm in response to rain or direct sunlight. When humans approach the nest, the nestlings have been described as uttering croaks, quacks, and whistles.

In ideal habitats, nests would be fairly close together. In some parts of Panama and Guyana, active nests were located 3 km (1.9 mi) away from one another, while they are within 5 km (3.1 mi) of each other in Venezuela. In Peru, the average distance between nests was 7.4 km (4.6 mi) and the average area occupied by each breeding pairs was estimated at 4,300 ha (11,000 acres). In less ideal areas, with fragmented forest, breeding territories were estimated at 25 km (16 mi). The female harpy eagle lays two white eggs in a large stick nest, which commonly measures 1.2 m (3 ft 11 in) deep and 1.5 m (4 ft 11 in) across and may be used over several years. Nests are located high up in a tree, usually in the main fork, at 16 to 43 m (52 to 141 ft), depending on the stature of the local trees. 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, cutting down the kapok tree is considered bad luck, which may help safeguard the habitat of this stately eagle. The bird also uses other huge trees on which to build its nest, such as the Brazil nut tree. A nesting site found in the Brazilian Pantanal was built on a cambará tree (Vochysia divergens). No display is known between pairs of eagles, and they are believed to mate for life. A pair of harpy eagles usually only raises one chick every 2–3 years. After the first chick hatches, the second egg is ignored and normally fails to hatch unless the first egg perishes. The egg is incubated around 56 days. When the chick is 36 days old, it can stand and walk awkwardly. The chick fledges at the age of 6 months, but the parents continue to feed it for another 6 to 10 months. The male captures much of the food for the incubating female and later the eaglet, but also takes an incubating shift while the female forages and also brings prey back to the nest. Breeding maturity is not reached until birds are 4 to 6 years of age. Adults can be aggressive toward humans who disturb the nesting site or appear to be a threat to their young.

The harpy eagle was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Vultur harpyja, after the mythological beast harpy. It is now the only species placed in the genus Harpia that was introduced in 1816 by the French ornithologist Louis Pierre Vieillot. The harpy eagle is most closely related to the crested eagle (Morphnus guianensis), the Papuan eagle (Harpyopsis novaeguineae) and the bat hawk (Macheiramphus alcinus), the four composing the subfamily Harpiinae within the large family Accipitridae. Previously thought to be closely related, the Philippine eagle has been shown by DNA analysis to belong elsewhere in the raptor family, as it is related to the Circaetinae. The specific name harpyja and the word "harpy" in the common name both come from Ancient Greek harpyia (ἅρπυια). They refer to the harpies of Ancient Greek mythology. These were wind spirits who flew the dead to Hades or Tartarus, purported to have the lower body and talons of a raptor and the head of a woman, standing anywhere from the height of a tall child to as high as a grown man; some depictions have the creatures possessing an eagle-like body with the exposed breasts of an elderly female human, a giant wingspan and the head of a grotesque, sharp-toothed, mutant eagle—something more akin to a goblin with wings. The upperside 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. A broad black band across the upper breast separates the gray head from the white belly. The head is pale grey, and is crowned with a double crest. The upperside of the tail is black with three gray bands, while the underside of it is black with three white bands. The irises are gray or brown or red, the cere and bill are black or blackish and the tarsi and toes are yellow. The plumage of males and females is identical. The tarsus is up to 13 cm (5.1 in) long.

Although the harpy eagle still occurs over a considerable range, its distribution and populations have dwindled considerably. It is threatened primarily by habitat loss due to the expansion of logging, cattle ranching, agriculture, and prospecting. Secondarily, it is threatened by being hunted as an actual threat to livestock and/or a supposed one to human life, due to its great size. Although the harpy eagle is not actually known to prey on humans and only rarely on domestic stock, a scientifically documented case of this species attacking an adult woman has been reported, and its large size and nearly fearless behaviour around humans reportedly making it an "irresistible target" for hunters. 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 wiped out from the Atlantic rainforest and is only found in appreciable 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 significant 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 (where a recent (March 2015) record was set for the Parque Estadual do Turvo) and Minas Gerais – the actual size of their total population in Brazil is unknown. Globally, the harpy eagle is considered vulnerable 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, 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 is found only in the Parana Valley forests at the province of Misiones. It has disappeared from El Salvador, and almost so from Costa Rica.

The harpy eagle was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Vultur harpyja, after the mythological beast harpy. It is now the only species placed in the genus Harpia that was introduced in 1816 by the French ornithologist Louis Pierre Vieillot. The harpy eagle is most closely related to the crested eagle (Morphnus guianensis), the Papuan eagle (Harpyopsis novaeguineae) and the bat hawk (Macheiramphus alcinus), the four composing the subfamily Harpiinae within the large family Accipitridae. Previously thought to be closely related, the Philippine eagle has been shown by DNA analysis to belong elsewhere in the raptor family, as it is related to the Circaetinae. The specific name harpyja and the word "harpy" in the common name both come from Ancient Greek harpyia (ἅρπυια). They refer to the harpies of Ancient Greek mythology. These were wind spirits who flew the dead to Hades or Tartarus, purported to have the lower body and talons of a raptor and the head of a woman, standing anywhere from the height of a tall child to as high as a grown man; some depictions have the creatures possessing an eagle-like body with the exposed breasts of an elderly female human, a giant wingspan and the head of a grotesque, sharp-toothed, mutant eagle—something more akin to a goblin with wings.