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The largest bird in the Americas, the greater rhea stands about five feet tall and weighs about 50 pounds. It has gray and brown plumage, with some white and black speckling, and a prominent black ring around the neck. Males are slightly larger than females, slightly grayer, and have a more pronounced neck ring. Young rheas are grayish, with black stripes.
Although the rhea cannot fly, it has very long wings, which are used like rudders when running. It has very powerful legs, each of which ends in three toes, as well as very keen eyesight and hearing.
Distribution and Habitat
The greater rhea is found in southeastern South America. It lives on the pampas, campos, cerrado, and open chaco woodland, but avoids open grassland. During the breeding season it stays near rivers, lakes, and/or marshes.
Males are generally solitary during the spring, while females and young travel in small groups. Males, females and young come together into large flocks at the end of the summer, and stay together through the winter months.
The breeding season runs from August to January, depending on the region. Males compete for breeding territories, within which they then court two to twelve females. Once mating has occured, the male builds a nest, which is a shallow hole in the ground with a rim surrounded by twigs and vegetation. Each female in his "harem" will lay one egg in his nest every other day over a period of seven to ten days. After the first two or three days of egg-laying, the male stays with the nest and eggs. Unlike most other birds, the male is the sole caretaker for the eggs and chicks, which hatch after six weeks. The eggs themselves are cream-colored and weigh about 600 grams each.
Females move from male to male throughout the breeding season and take no part in caring for the chicks. Young rheas mature fairly quickly, becoming almost as large as their parents by their sixth month. Sexual maturity is reached at about two years of age.
Rheas are omnivorous, but prefer broad-leaf plants and clover. They also eat a variety of seeds, roots, and fruits, as well as insects, lizards, frogs, small birds, and snakes.
Other Habits and Behaviors
Males are very protective of eggs and chicks, and will charge at anything that comes too close, including female rheas.
When not guarding a nest or eggs, rheas will usually run from potential danger. If unable to run, a rhea can suddenly disappear in the tall grass by lying flat on the ground and sticking its head straight out in front of its body.
Rheas are considered a pest by farmers because they will eat almost any crop, and are often killed to prevent potential crop damage. They are also killed for their feathers, which are used for feather dusters, and skin, which makes a fine leather. Adults and eggs are eaten by locals. These factors, combined with the loss of habitat due to increased agriculture, have placed the greater rhea on the "near threatened" list.
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This page was last updated on February 10, 2019.