Giant antpitta  (Grallaria gigantea)

The giant antpitta is classified as Vulnerable (VU) on the IUCN Red List (1).

The giant antpitta (Grallaria gigantea) is a secretive bird, which is rarely seen but often heard. The dull, olive-brown to brown back and wings of the adult enable it to remain well camouflaged, although the crown of the head is bright chestnut. The giant antpitta’s most distinctive feature is its reddish-brown underparts with bold, wavy, dark or black barring on the throat and chest (2).

Chicks of the Grallaria genus are either pale-skinned with light or grey down, or dark-skinned with dark down. Inside the bill, the mouth is a distinctive bright orange to red-orange (3).

The song of the giant antpitta may be heard in the morning before the dawn chorus, and at irregular intervals throughout the day (2). Its song is made up of fast, low-pitched trills, which increase in volume and pitch and are repeated after a few seconds (4).

There are three subspecies of giant antpitta, although it has been suggested that one of these may be a distinct species (5). The subspecies Grallaria gigantea lehamanni differs from Grallaria gigantea gigantea in that it is a more olive-brown, while Grallaria gigantea hylodroma is brighter and has fewer bars on its underside (2).

The giant antpitta has a very small range and is known only from two countries. It can be found in Cauca and Huila in southwest Colombia, and a few localities in Ecuador, including Napo and Pichincha (2).

Inhabiting cloud forest, particularly in swampy and humid areas, the giant antpitta prefers level ground rather than the steep slopes of the Andes (2). It generally lives at high elevations, with populations of G. g. gigantea and G. g. hylodroma occurring at elevations of between 1,200 and 2,600 metres, and G. g. lehmanni at elevations above 3,000 metres (2) (5).

Although it may sometimes be found foraging in open pastures close to the rainforest edge, the giant antpitta spends most of its time within the rainforest itself (2). Its diet includes large beetles, slugs and grubs, but it may also eat tadpoles and frogs, as the giant antpitta has been observed foraging near streams and stagnant puddles (2) (5).

It is thought that giant earthworms (Rhynodrylus spp.) are the giant antpitta’s preferred food. The giant antpitta has been observed pounding its beak into the soil with sudden, repeated movements and giant earthworms have subsequently been found with neat beak marks (4). Foraging has been observed throughout the day, from thirty minutes before dawn to thirty minutes after dusk (2).

The giant antpitta is thought to breed in the wet season, between February and June, as fledglings have been seen at this time and this is also when its birdsong can be heard at higher elevations (3).

In antpittas (Grallaria and Grallaricula spp.), both the male and female contribute to the nest, which is constructed using dry sticks and lined with materials including moss and dry grass. The nest is a round, open cup shape, situated no more than three metres above the ground. It is either built with many small supports, such as branches or vines, or against larger structures like fallen logs and tree stumps (3).

Birds in the genus Grallaria lay two eggs, which are turquoise to blue-green and have no markings. Both adults incubate the eggs for around 17 to 20 days and spend around 90 percent of their time at the nest. After hatching, the nestlings are fed on giant earthworms and insects. The young chicks usually fledge the nest 15 to 19 days after hatching (3).

Antpitta eggs are predated by birds, such as the turquoise jay (Cyanolyca turcosa), and other predators include the mountain coati (Nasuella olivacea) and the tayra (Eira barbara). If a predator should pass a nesting antpitta, the bird generally responds by freezing and remaining motionless, only fleeing if there is no other option available (3).

Habitat loss is the main threat to the giant antpitta, with cloud forest being cleared at an ever-increasing rate (2). Forest on flat land has been cleared for agricultural use since the early 20th century, and so the giant antpitta is particularly at risk due to its preference for level ground (2) (4).

Three National Parks (Sumaco-Napo Galeras, Llanganates and Sangay) and two Ecological Reserves (Cayambe-Coca and Antisana) cover 60 percent of the giant antpitta’s Ecuadorian range (6).

Recent estimates place the global giant antpitta population at 1,000 to 2,500 individuals (5). However, recent sightings have been few, and the exact number of giant antpittas in the wild is uncertain. It has been suggested that the giant antpitta’s status should be upgraded to Endangered (EN) on the IUCN Red List (6).

Further study is needed to determine the size of the giant antpitta populations in the National Parks of Colombia and Ecuador. More information is also needed to establish exactly when the giant antpitta breeds, as this is where deforestation is likely to cause most harm (3) (5).

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on the giant antpitta see:

• BirdLife International - Giant antpitta:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=5071