The Seriemas are a small and ancient family (Cariamidae) of tropical South American birds related to the rails and bustards.
There are two species.
Both species are around 80 cm long; the Red-legged Seriema is slightly bigger than the Black-legged. They forage on foot and run from danger rather than fly (though they can fly for short distances, and they roost in trees). They have long legs, necks, and tails, but only short wings, reflecting their way of life. They are brownish birds with short bills and erectile crests, found on fairly dry open country, the Red-legged Seriema preferring grasslands and the Black-legged Seriema preferring scrub and open woodland.
They give loud, yelping calls and are often heard before they are seen.
Ecologically they are the South American counterpart of the Secretary Bird
. They feed on insects, snakes, lizards, frogs, young birds, and rodents, with small amounts of plant food (including maize and beans). They often associate with grazing livestock, probably to take insects the animals disturb. When seriemas catch small reptiles, they beat the prey on the ground (Redford and Peters 1986) or throw it at a hard surface to extinguish life and also to break the bones. If the prey is too large to swallow whole, it will be ripped into smaller pieces with a sickle claw remniscent of those in Deinonychosaurs
, and Troodon
. (pictured below) by holding the prey in the beak and tearing it apart with the claw.
Seriemas build bulky stick nests. They lay two (or three) white or buff eggs sparsely spotted with brown and purple. The female does most of the incubation, which last from 24 to 30 days. Hatchlings are downy but stay in the nest for about two weeks; then they jump down and follow both parents. They reach full maturity at the age of four to five months.
Relationship with humans
People sometimes capture young seriemas and tame them, keeping them with poultry to warn off predators.
The two extant species of seriema are thought to be the closest living relatives of a group of gigantic (up to ten feet tall) carnivorous "terror birds", the phorusrhacids
, which are known from fossils
from South and North America. Several other related groups, such as the idiornithids
were part of Palaeogene
faunas in North America
and possibly elsewhere too. However, the fossil record of the seriemas themselves is not good, with a single prehistoric species (Chunga incerta
) having been described to date. Some of the fossils from the Eocene
fauna of the Messel Pit
) of has also been suggested as serimas
, though their status remain inconclusive.
The seriemas have an extensible second claw that is raised from the ground. Although this resembles the "sickle claw" of Velociraptor and its relatives, it is probably not used in the same way.
Names for these birds in the Tupian languages
, which are explained as meaning "crested" (New Shorter Oxford English Dictionary