The Red-legged Seriema or Crested Cariama (Cariama cristata) is a mostly predatory terrestrial bird in the seriema family (Cariamidae), included in the "Gruiformes" in the old paraphyletic circumscription, but increasingly placed in a distinct order Cariamae (along with three extinct families). The Red-legged Seriema inhabits grasslands from Brazil south of the Amazon to Uruguay and northern Argentina. The area over which it occurs is estimated at 5.9 million km², though the bird is not found everywhere in this region of course. The species is absent from the Mata Atlântica and planalto uplands along the coast of Brazil.

Description Close-up of a red-legged seriema's head.

It is 75 to 90 cm (30 to 36 in) long, with a fairly long neck, tail, and legs. The plumage is medium brown above with black markings; pale brown on the head, neck, and breast; and white on the belly. The tail has a black band near the tip and a white tip. The beak and legs are red, and the eyes are yellow. Soft feathers emerge from the base of the bill to form a fan-shaped crest.

Many other characteristics are shared with the Black-legged Seriema (Chunga burmeisteri), the only other living member of its family. Some of these traits are discussed in the Cariamidae article.

The song has a quality described as "a cross between 'the serrated bark of a young dog and the clucking of turkeys'". At the loudest part of the song, the bird has its neck bent so its head is touching its back. Both members of a pair as well as young down to the age of two weeks sing; often one member of a family starts a song just as another finishes, or two sing simultaneously. The song can be heard several kilometres away; in Emas National Park, Brazil, in 1981"?1982, observers often heard four Red-legged Seriemas or groups singing at once.

The full song consists of three sections:

1. Repeated single notes at constant pitch (1,200 to 1,300 Hz) and duration but increasing tempo
2. Repeated two- or three-note subphrases of slightly higher pitch with increasing tempo
3. Subphrases of up to 10 notes, shorter ones rising in pitch and longer ones falling, two-subphrase cominations increasing in number of notes and tempo and then decreasing in tempo.

Ecology The sickle claw of a red-legged seriema, used in fighting.

The Red-legged Seriema prefers grassland habitat to any other. Though it likes to inhabit lush meadows near rivers, it will not readily move into wetlands or crop fields. It is usually seen singly or in pairs, but sometimes in groups up to four, apparently families. It typically walks on the ground and can easily run faster than a human in its habitat. It will flee a car on foot at speeds up to 25 km/h (15 mi/hr) before flying.

In one conflict between two birds, they jumped at each other feet-first, keeping their balance by flapping.

This species nests on the ground or in a bush or tree up to 3 m above the ground. In the latter case adults jump into the nest rather than fly.

The seriema has been know to attack humans, especially during nesting season.