Greater Rhea

The Greater Rhea is the largest bird native to South America, a flightless grassland species with loose, shaggy gray-brown plumage and long bare legs. Superficially resembling a smaller Ostrich, it has a long neck, a flattened head, and large dark eyes suited to spotting predators across open terrain.

Rheas are gregarious birds, typically seen moving in small flocks across the pampas and savannas of central and southern South America.

Key Field Marks

• Large flightless body with grayish-brown, shaggy plumage
• Long bare gray legs with three forward-facing toes
• Long neck and small flattened head
• Males may show darker, blacker feathering on the neck during breeding
• Loose flocks in open grassland habitat

Similar Species

• The Lesser (Darwin's) Rhea is smaller, paler, and found farther south in Patagonia and the Andean altiplano, with white-tipped feathers giving a more speckled look
• No other large flightless bird occurs within its South American range

Range

Central and eastern South America, including Brazil, Paraguay, Uruguay, Bolivia, and Argentina.

Habitat

Open grassland, pampas, savanna, and agricultural land with scattered low vegetation; avoids dense forest.

Migration

Non-migratory, though flocks may shift locally with seasonal food and water availability.

Behavior

Gregarious for much of the year, forming flocks of a dozen or more birds, often mixing with grazing mammals such as deer or cattle. Runs swiftly with wings held out for balance when fleeing danger.

Voice

Generally silent, but males give a deep booming or roaring call during the breeding season to attract mates and declare territory.

Feeding

Omnivorous grazer, eating broad-leaved plants, seeds, fruit, and roots, along with insects, small reptiles, and other small animals.

Nesting & Breeding

Polygynous like other large ratites: a male mates with several females who lay eggs in a shared ground nest, and the male alone incubates and raises the chicks.