Harpy Eagle

A huge, iconic eagle of the rainforests of Central and South America, the harpy eagle (*Harpia harpyja*) is one of the largest and most powerful birds of prey in the world. This impressive species is named after the ‘harpies’ of Greek mythology, which were winged monsters with sharp claws and a woman’s face.

The harpy eagle has a long tail and broad, rounded wings that can span up to two metres across. As in many other forest raptors, its wings are relatively small for its size, giving the harpy eagle great agility and enabling it to dodge through branches and trees while flying below the forest canopy. The harpy eagle’s large black bill is strongly hooked, and its legs and toes are large and robust, with massive talons. Together with its great size, these imposing weapons make the harpy eagle a formidable predator.

The adult harpy eagle has blackish upperparts, a grey head and neck, and a distinctive dark, double-pointed crest, which is usually raised. The feathers of the face form a facial ‘disc’. The underparts of the harpy eagle are white, with a broad black band across the chest and black barring on the thighs. The tail is black with three greyish bands and a greyish-white tip, while the undersides of the wings are barred black and white. The harpy eagle has greyish to brown eyes, a black cere and yellow legs and feet.

The male and female harpy eagle are similar in appearance, although the female is significantly larger, weighing up to twice as much as the male. Juveniles are whitish to grey overall, with a whitish crest, brownish-grey upperparts and several dark bars on the tail. The young bird gradually becomes darker with age until acquiring its full adult plumage at about four years old.

The harpy eagle’s call is a plaintive, penetrating scream, described as ‘*wheeeeeeee*’ or ‘*wheeeeoooooo*’, which is repeated several times. Juvenile harpy eagles which are still dependent on the adults can often be observed begging for food by raising their wings in a shrug-like movement, while repeating a high-pitched ‘*whee-e-e-e, whee-e-e-e*’. Despite this eagle’s enormous size, it is a surprisingly inconspicuous species and is usually only seen when it crosses rivers or forest openings.

### **Biology**

A powerful predator, the harpy eagle hunts a range of medium-sized animals, particularly arboreal mammals such as monkeys and sloths, as well as some terrestrial mammals such as deer, peccaries, agoutis (*Dasyprocta*species), foxes and armadillos. The harpy eagle also preys on a variety of birds and reptiles, including macaws, curassows, snakes and iguanas.

The harpy eagle usually hunts by watching for potential prey from a perch, before flying through the forest with remarkable speed and agility and snatching its victim from the trees. Most prey is taken to the top of a tree to be eaten, but heavier items may be dragged to a fallen trunk. Due to their smaller size, male harpy eagles take smaller prey than females, but an adult female is capable of carrying prey remains weighing up to three or four kilograms back to the nest. The harpy eagle’s excellent hearing and the arrangement of its facial feathers into a disc shape may help it to locate prey by sound. A monogamous species, the harpy eagle is usually seen alone or in pairs. This species has been recorded breeding between April and November in Brazil, Argentina and Guyana, but may potentially breed in any month of the year.

Both the male and female harpy eagle help to construct the nest, which is a large platform of sticks, built high in a tall emergent tree and lined and decorated with green leaves. Two dull white eggs are usually laid, and are incubated by the female for about 56 days. In almost every case, only a single chick survives. The male harpy eagle brings food to the nest every few days during the incubationperiod, and also while the chick is being raised. The young harpy eagle fledges at about 4.5 to 6 months old. After fledging, the juvenile harpy eagle remains close to the nest site and is dependent on the adults for a further 8 to 12 months. The juvenile may remain close to the nest until it reaches two years of age. This slow development of the young means that the adult pair cannot breed more than once every two to three years.

### **Range and Habitat**

The harpy eagle has an extensive distribution across Central and South America, from southern Mexico southwards to Paraguay, southern Brazil and north-eastern Argentina. However, it is quite sparsely and patchily distributed across its range and is thought to be locally extinct in some areas, particularly in parts of Central America. Primarily a lowland species, the harpy eagle typically inhabits tropical and subtropical evergreen forest below elevations of about 900 metres, although it may occasionally be found up to 2,000 metres. This species is able to adapt to a degree of habitat disturbance, as long as sufficient forest patches remain.