The Greater Rhea (Rhea americana) is the largest bird in South America, at almost 5 ft in height and weighting up to 60 lbs. This large flightless bird feeds mainly on plant matter, including leaves, roots, seeds and fruits. It also takes insects and small animals, such as lizards, frogs, small birds and even snakes, and sometimes catches flies that have gathered around carrion. The greater rhea also commonly swallows pebbles, which help to grind down food in the gizzard, and can often be seen feeding alongside herds of pampas deer, guanacos, vicunas, or domestic livestock…
Also known as the Lesser Rhea, Darwin’s rhea is a species of rhea (flightless birds related to ostriches) found only in the regions of Patagonia and Altiplano in southern South America. Like other ratites Darwin’s rhea is mainly a herbivore and feeds mostly on saltbush, grasses, and cactus fruits, however it will eat small reptiles and insects as-well.
Darwin’s rheas are sociable birds and are often found in large groups of 10-30 individuals, however during the mating season the males will become highly aggressive and will defend their nests with their lives. They become so aggressive that females will have to lay the later eggs near the nest, instead of inside it, for the males to roll in. Currently Darwin’s rhea is listed as near threatened due to a combination of habitat loss, hunting and egg collecting.
Southern Cassowaries (Casuarius casuarius) are large, flightless birds that are related to emus and found only in Australia and New Guinea. The name cassowary comes from a Papuan name meaning ‘horned head’, referring to the helmet of tough skin born on the crown of the head. This helmet (or casque) slopes backwards and is used to push through vegetation as the cassowary runs through the rainforest with its head down; it also reflects age and dominance.
For most birds, females are stuck with child care. But not so for South America's greater rhea, a large flightless bird related to ostriches and emus (pictured, an adult and baby in Argentina).
Females mate with several males during the breeding season, and many birds will lay their eggs in one nest created by a male. The male then incubates up to 50 eggs for six weeks and cares for the newly hatched young. The dads aggressively guards the babies, charging at any animal—even a female rhea—that approaches.
Because females put such a “heavy investment” of energy and resources into producing large eggs, it makes sense for males to pick up the responsibility of caring for the offspring.
(via: National Geo) (photo: Andres Morya, Visuals Unlimited/Getty Images)
Diet: Omnivore Average life span: 15 years Size: 3 - 5 ft (0.9 to 1.5 m) Weight: 50 lbs (20 kg)
These large South American birds roam the open pampas and sparse woodlands of Argentina and Brazil.
The greater rhea is the largest of all South American birds and is related to ostriches and emus. These flightless birds use their long, powerful legs to outrun trouble. Although their large wings are useless for flight, they are used for balance and for changing direction as the bird runs.
Greater rheas are polygamous, so males have many different mates. Females lay their eggs—one every other day for a week or ten days—in a ground nest of the male’s design. Several females deposit their eggs in the same nest, which may hold 50 eggs or more…
The flightless ostrich is the world’s largest bird. They roam African savanna and desert lands and get most of their water from the plants they eat.
Though they cannot fly, ostriches are fleet, strong runners. They can sprint up to 43 miles (70 kilometers) an hour and run over distance at 31 miles (50 kilometers) an hour. They may use their wings as “rudders” to help them change direction while running. An ostrich’s powerful, long legs can cover 10 to 16 feet (3 to 5 meters) in a single stride. These legs can also be formidable weapons. Ostrich kicks can kill a human or a potential predator like a lion. Each two-toed foot has a long, sharp claw.
Ostriches live in small herds that typically contain less than a dozen birds. Alpha males maintain these herds, and mate with the group’s dominant hen. The male sometimes mates with others in the group, and wandering males may also mate with lesser hens. All of the group’s hens place their eggs in the dominant hen’s nest—though her own are given the prominent center place. The dominant hen and male take turns incubating the giant eggs, each one of which weighs as much as two dozen chicken eggs.
(read more: National Geo) (photo: female pictured, by Carsten Peter)
On Jan. 26, one of the Zoo’s female double-wattled cassowaries took an interstate trip to the Virginia Zoo, where she will be paired with a mate and (hopefully) contribute to North America’s breeding program. Both she and the Zoo’s remaining cassowary—a female—have lived at the Smithsonian’s National Zoo for more than 20 years. Come visit our cassowary in the outdoor exhibit behind the Bird House next to the rheas.