Harpy Eagle

How to find it

Birders wanting a reliable Harpy Eagle usually travel to eastern Panama or the Amazon, to visit known nests. In Costa Rica, Corcovado National Park on the Osa Peninsula is often named as the best bet, ideally with a guide, and sightings remain very unlikely.

Corcovado requires a licensed guide by law, and a good local guide may double or triple the birds you see, because they know the calls and fruiting trees. The 2022 bird was spotted in a roadside tree where forest meets both sides of the road, which looked like a good place for an eagle to cross. Local birders who rushed there needed two to three hours to arrive and the eagle was gone, and later searches did not refind it. A bird that stays under cover and ranges widely rewards patience, not a dash.

How to recognise it

This is a huge eagle with a slate black back, a white belly and a double crest on a pale grey head. It has very heavy talons.

Adults reach about 1 m in length, with a wingspan of up to about 2.2 m. Females are larger than males, though only slightly. These sizes describe the species across its whole range, not Costa Rican birds specifically.

The guide who found the 2022 bird in the north identified it by its size, the feathers of the crest and the plumage tones. Those are the same points to note if you think you have one.

Behaviour and diet

Harpy Eagles rarely soar. They wait under forest cover and then fly out quickly to grab prey. This habit, plus huge territories, makes them hard to see even where they are healthy. They hunt in the canopy and perch on emergent trees.

They feed mainly on tree-dwelling mammals, and sloths make up much of the diet. Monkeys and opossums are also taken, along with reptiles, birds and occasionally domestic livestock.

When to see it

The only dated recent record is the 2022 Boca Tapada bird, seen in late July. No season is known when the species is easiest to see.

Similar birds

Harpy Eagle is easily confused with Crested Eagle, a Costa Rican biodiversity specialist has noted. Both are very rare in the country, so any such sighting should be carefully confirmed. The few Crested Eagle records came from Corcovado in 2012, near Golfito in 2016 and near Arenal volcano in 2020.

Names and lore in Costa Rica

In Costa Rica the bird is called águila arpía, sometimes spelled águila harpía. The Association's list also gives the name Aguilucho. A Costa Rican birding blog calls seeing one here one of the biggest challenges a Costa Rican birder can face.

Status and conservation

The AOCR list marks it as a resident (R), but it is considered rare in Costa Rica and was thought extinct here before 2009.

Photography tips

The 2022 bird was spotted in a roadside tree where forest meets both sides of the road, so quiet forest edges and road crossings are worth scanning. Because Harpy Eagles stay under cover and range widely, a sighting is brief. Keep a camera ready and note the size, crest feathers and plumage tones.

A licensed local guide, required in Corcovado, knows the calls and fruiting trees and can help you find the other wildlife of the forest.