Eudocimus ruber
scarlet ibis

Eudocimus ruber is found in northern South America, stretching from Venezuela to Eastern Brazil. It is nomadic, with seasonal shifts and migrations between different coastal locations and interior wetlands. (Hancock, Kushlan, and Kahl, 1992; Utah's Hogle Zoo, 2001)

Eudocimus ruber prefers swampy environments such as mud flats and shallow bays. It tends to reproduce and nest on dense brush-covered islands and mangroves near the mouths of rivers. (Utah's Hogle Zoo, 2001)

Eudocimus ruber is in the same family as spoonbills. Ibises have slightly webbed feet and a thin, down-curved bill. They fly with the bill forward and neck held straight. All ibises are long-legged and long-necked wading birds, but E. ruber can be characterized by its stunning red plumage and its glossy blue-black wing tips. This bright red color fades to pink in captive zoo birds, unless they are given a specific diet, which consists of high levels of protein and shrimp meat. Although the adults are brightly colored, the young are dull, with a grayish-brown color and white underbellies. Females and males are identical in coloration, but the male's body size and bill length are much larger. Scarlet ibises weigh between 0.772 to 0.935 g, are 55.8 to 76.2 cm long and have wingspans of 52.1 to 56.1 cm. Their metabolic rate can reach 1432 cm^3 oxygen/hour. (Hancock, Kushlan, and Kahl, 1992; Microsoft Corporation, 2001; Utah's Hogle Zoo, 2001)

Young E. ruber have approximately a 50% mortality rate. In general, colonies suffer from high mortality rates due to predation and lack of food. Although information on actual lifespan of E. ruber is limited, data on its North American relative, Eudocimus albus, can be used as an adequate estimate. Eudocimus albus usually lives for about 16 years in the wild and 20 years in captivity; the oldest known captive individual lived 31 years. (Hancock, Kushlan, and Kahl, 1992; Hill, 2001; Ricklefs, 2000)

Eudocimus ruber is a highly communal species. It is social both during nesting and when searching for food. Eudocimus ruber will fly in large flocks between different feeding and roosting sites. In flight, the birds will soar and also glide at great heights and speeds. If disturbed, sometimes all the birds of a nesting area will take flight at once. Territorial disputes between males are settled by size. (Hancock, Kushlan, and Kahl, 1992)

Home Range

The range for E. ruber is varied and extensive, because of nomadic movements between nesting and foraging sites. Shifts occur between the interior wetlands of northern South America to coastal locations. More specifically, birds forage between the higher and lower llanos of South America. Nesting then takes place in northwestern Colombia and along the Atlantic coast and into Brazil where it nests along the northeastern coast. (Hancock, Kushlan, and Kahl, 1992)

Eudocimus ruber produces a honking noise to communicate disturbances in the nest and also uses the noise in courtship. The young have a shrill cry, that they use to let parents know that they are in need of food. Touch is important during courtship. The males and females make greeting displays to one another and then wrap necks. The male produces the honking noise during courtship, while the female produces more of a squealing sound. (Hancock, Kushlan, and Kahl, 1992)

Eudocimus ruber forages for food by either probing in water with its long bill or pecking for prey items on soil surfaces. Their main diet consists of crustaceans and aquatic invertebrates. Crayfish and small crabs compose a bulk of the diet, along with aquatic insects. Frogs, mollusks, small snakes and small fish are also prey for E. ruber. (Hancock, Kushlan, and Kahl, 1992; Utah's Hogle Zoo, 2001)

Eudocimus ruber faces the greatest risk of predation by large cats (family Felidae) and birds of prey (order Falconiformes). Their best defense is the fact the E. ruber stays together in large groups. That way, males can use their larger size to defend their young and their female mates. The large grouping is also useful because the birds produce warning calls to warn the others of danger. (Hancock, Kushlan, and Kahl, 1992; Utah's Hogle Zoo, 2001)

Eudocimus ruber lives among many other wading birds. While it can live harmoniously with other species, it also defends its individual space very aggressively. Other birds often steal the eggs of E. ruber, thus it must be protective of its territory. Because of its large colonial sizes (which can have anywhere from 20 to 600 nests, and sometimes even up to 2000 nests), E. ruber contributes significantly to the energy flow of organisms in the environment in which it lives. In one wetland, it has been noted to be responsible for 10% of the energy flow through the community.

This species forages for food with many other types of wading birds, such as storks and spoonbills and specifically has been seen living with Brazilian wading ducks. One reason that the species may be mutualistic in sharing feeding areas is that if it allows for a great number of birds to feed communally at its site, then it has a better chance to hide from predators among all the other birds. Also, many wading birds together stir up the shallow water and disturb the prey so that they are easier to find and catch. (Hancock, Kushlan, and Kahl, 1992)

The foraging technique that E. ruber uses sends it into many different environments to find its meals. Unfortunately, their foraging can lead the birds to beaches, gardens, yards, playing fields, golf courses, and even agricultural fields where it can disrupt the residential lives and activities of people. While no major economic downfalls or disturbances have been reported as a result of E. ruber, many consider the large number of birds in these public areas to sometimes be a nuisance. (Hancock, Kushlan, and Kahl, 1992)

The importance of the E. ruber dates back to the 16th century when Indian tribes would use the bright feathers for adornment and also eat the meat of the bird. Eudocimus ruber meat and eggs are still used as food by humans and the feathers continue to be used as decorative objects by people both inside and outside of the Indian community. (Frederick et al., 1990)

Many environmental and human threats exist for E. ruber. Overhunting, the harvesting of eggs and the selling of young as pets in open-markets are just three of the things affecting population sizes of E. ruber. Other crucial aspects threatening the species revolve around habitat loss. Nesting ground destruction and loss of foraging and feeding grounds are serious problems, along with heavy pollution in these now limited areas. Disturbance of breeding and foraging areas because of recreational activities, such as boating, is also a complication for colonies of E. ruber. There are laws and regulations that have been issued to protect E. ruber habitats and also gaurd the animal from hunting. However, in many areas, law enforcement is weak. In order to sustain the populations of E. ruber, pollution must be controlled in their breeding and feeding areas and people living in rural areas should be education about the bird. They are protected by the US Migratory Bird Treaty Act and are listed as Appendix II by CITES. (Frederick et al., 1990)