Harpy eagles are iconic, almost prehistoric-looking birds of prey that regularly feature near the top of ‘birds-to-see-before-you-die’ lists. Seeing one of these majestic eagles in the wild is a truly special moment for birders.
What are harpy eagles?
The harpy eagle is one of the world's biggest and most impressive birds of prey.
How big are harpy eagles?
Though harpy eagles are not quite the largest bird of prey – that title belongs to the condors – the harpy eagle is arguably the most powerful. It measures around 0.9–1m from meat-cleaver beak to tail. The wings, which span up to 2m, are relatively short for the eagle’s size, but combine with a long tail to give this mighty bird – like a giant sparrowhawk – great manoeuvrability in flight. The tail acts like a rudder as it steers through the dense forest. As with sparrowhawks, females are considerably larger than their mates – at a maximum of 9kg, they weigh up to twice as much.
Where do harpy eagles live?
Celebrated as Panama’s national bird, the harpy eagle occurs in greater numbers there than anywhere else in Central America. Measured by confirmed active nests, Panama’s harpy population is the third-largest in the species’ entire range, from southern Mexico south to north-east Argentina. Only Venezuela and Brazil have more harpies. But Panama hosts the highest density, with an estimated 800 breeding pairs by some estimates. Most are in the Darién, the easternmost province.
How do harpy eagles hunt?
Harpies hunt mainly by making short flights from one tree to another, pausing at each look-out to locate unwary sloths and monkeys, their chief prey. The dark interior of the forest renders hearing more important than vision. These eagles have a large, circular facial disc, like that of owls and harriers, which directs sound into the ears and enhances hearing in a similar way to cupping your ears with your hands.
What do harpy eagles eat?
Harpies’ immensely thick legs and feet are powerful enough to rip sloths and monkeys from branches. The talons are the largest of any raptor, the sabre-like hind claw being up to 7cm long. A big female harpy can fly off clutching a male howler monkey or adult brown-throated sloth weighing almost as much as she does. Even so, many hunting attempts will end in failure.
Harpies also prey on other arboreal mammals, such as kinkajous, opossums and olingos, as well as iguanas and large birds such as macaws. Very occasionally they may take the odd ground-dwelling animal, such as a young peccary, armadillo or snake.
How do harpy eagles reproduce?
Harpy eagles are one of a number of animals that mate for life. They share the task of building the impressive stick nest structure, often wedged in a large fork of a tree, adding green leaves and seed pods to the shallow cup.
Although no courtship rituals are known, the male and female have been observed to call softly to one another and rub their powerful bills together while nest-building, presumably helping to reinforce the pair bond.
Harpy eagles breed only once every two or three years, one of the longest reproductive periods of any raptor. While pairs may nest again in the same tree, there is no guarantee: they might move elsewhere for subsequent nesting attempts
Female harpies lay two eggs, but are not known to rear more than one chick, failing to incubate
the second egg (should both eggs hatch, the younger chick will likely fail to compete with its sibling).
The incubation period is about eight weeks. The youngster, which has white down, generally fledges at between six and seven months of age, but even after that length of time may still beg for food from its parents. It will be protected by them for a further three or four months.
The immature harpy eagle goes through a sequence of plumages and will remain within 100m or so of the nest for at least 15 months – and in the same general area for up to 30 months.
Observations of captive birds indicate that females may not breed until they are five years old, and males at some stage before they are nine.
How long do harpy eagles live for?
Should a harpy eagle evade disease and injury, and persecution by humans, it stands a chance of surviving 25 or even 35 years.
Why are they called harpy?
Harpy eagles are named after Harpies, Greek mythological creatures that were half-human and half-bird.
What is the conservation status of the harpy eagle?
The harpy eagle is classified by the IUCN as Vulnerable.
The Global Raptor Information Network prefers to class the species as Critically Endangered in Mexico and Central America, and as Vulnerable in South America.
Why are numbers declining?
Deforestation is an important factor, but the main threat is persecution. Eagles are killed for trophies, because they are wrongly seen as a threat to chickens, pigs and other livestock, and by some native Americans for their magnificent crest and wing feathers, used to make arrowheads and head-dresses.
Discover other fascinating eagle facts