Harpy Eagle

Identificazione

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.<p>Female harpy eagles typically weigh 6 to 9 kg (13 to 20 lb). One source states that adult females can weigh up to 10 kg (22 lb). An exceptionally large captive female, "Jezebel", weighed 12.3 kg (27 lb). Being captive, however, 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 may range in weight from 4 to 6 kg (8.8 to 13.2 lb). The average weight of adult males has been reported as 4.4 to 4.8 kg (9.7 to 10.6 lb) against an average of 7.3 to 8.3 kg (16 to 18 lb) for adult females, a 35% or higher difference in mean body mass. Harpy eagles may measure from 86.5 to 107 cm (2 ft 10.1 in to 3 ft 6.1 in) in total length and have a wingspan of 176 to 224 cm (5 ft 9 in to 7 ft 4 in). Among the standard measurements, the wing chord measures 54–63 cm (1 ft 9 in – 2 ft 1 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 exposed culmen from the cere (the beak) is 4.2 to 6.5 cm (1.7 to 2.6 in). Mean talon size is 8.6 cm (3.4 in) in males, and 12.3 cm (4.8 in) in females.<p>It is sometimes cited as the largest eagle alongside the Philippine eagle, which is somewhat longer on average (between sexes averaging 100 cm (3 ft 3 in)) but weighs slightly less, and the Steller's sea eagle, which is perhaps slightly heavier on average (mean of three unsexed birds was 7.75 kg (17.1 lb)). <p>The harpy eagle may be the largest bird species to reside in Central America, though large water birds such as American white pelicans (Pelecanus erythrorhynchos) and jabirus (Jabiru mycteria) have scarcely lower mean body masses. The wingspan of the harpy eagle is relatively small, though the wings are quite broad, 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 that 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.<p>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.

Tassonomia

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.<p>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.

Nome scientifico

Harpia harpyja

Autorità

(Linnaeus, 1758)

Ordine

Accipitriformi

Famiglia

Accipitridae

Genere

Harpia

Areale e habitat

Relatively rare and elusive throughout its range, the harpy eagle is found from southern México (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 Panamá. 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 Panamá 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 (6,600 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.

Migrazione

Specie stanziale

Comportamento

Comportamento migratorio: Specie stanziale.

Conservazione

Tendenza della popolazione: in diminuzione.

Tendenza della popolazione

in diminuzione