The harpy eagle (Harpia harpyja) is a neotropical species of eagle. It is also called the American harpy eagle or Brazilian 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 and most powerful raptor found 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. In Brazil, the harpy eagle is also known as royal-hawk (in Portuguese: gavião-real). The genus Harpia, together with Harpyopsis and Morphnus form the subfamily Harpiinae.
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. The only member of the genusHarpia, 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 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 species name harpyja and the word harpy in the common name harpy eagle both come from Ancient Greek harpyia (ἅρπυια). They refer to the harpies of Ancient Greek mythology. These were wind spirits that took the dead to Hades or Tartarus, and were said to have a body like a vulture and the face of a woman.
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 iris is 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 are 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 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, 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 5.95 kg (8.8 to 13.1 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 7.35 to 8.3 kg (16.2 to 18.3 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 in to 3 ft 6 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 is 4.2 to 6.5 cm (1.7 to 2.6 in). Mean talon size is 8.6 cm in males, and 12.3 cm in females.
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 3 unsexed birds was 7.75 kg (17.1 lb)). 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 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.
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.