Screamers: Anhimidae

Updated About encyclopedia.com content Print Article Share Article
views updated

SCREAMERS: Anhimidae

HORNED SCREAMER (Anhima cornuta): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

Screamers are large, goose-like birds that swim well and live in and near fresh water. They have a horn-like projection on top of their heads, and a short, downcurved bill. Their legs are long and thick, and their feet are only shallowly webbed. Wings are long and broad, which makes them able to soar well. They weigh 5 to 7 pounds (2 to 3 kilograms) and measure 28 to 36 inches (71 to 92 centimeters) long.

Each wing has a sharp, spur-like outgrowth of bone. These spurs, which are used as weapons, are covered with keratin, the same material that makes up hair and fingernails. Body coloration is black or gray on top with lighter hues below.


GEOGRAPHIC RANGE

Screamers are found in South America, from Venezuela and Colombia to Uruguay and northern Argentina.


HABITAT

Screamers live in swamps, marshes, lagoons, and lakes as well as flood plains, meadows, and savannas (tropical or subtropical plant communities characterized by low trees and shrubs as well as grasses and herbs).


DIET

Screamers are vegetarian birds that feed on aquatic plants and seeds. They do not dive for food.

BEHAVIOR AND REPRODUCTION

Screamers remain in their breeding range year-round and are somewhat social. Outside the breeding season, they tend to flock together. And though they swim well, screamers mostly live on land. Their long toes make them able to walk on aquatic vegetation and floating mats. Screamers got their name because of their very loud vocalizations.

Screamers are solitary nesters that build their nests out of vegetation, weeds, and sticks on or near the water. The female lays two to seven spotted eggs, and incubation (warming sufficient for hatching) lasts forty-two to forty-five days. Parents take turns incubating, and the male helps care for newborns. Chicks leave the nest within a few days. Babies first fly at ten to twelve weeks, and they no longer require parental care around twelve to fourteen weeks.

Screamers are seasonally monogamous (muh-NAH-guh-mus; having just one mate each year). The expected life span in the wild is eight to ten years. Predators include skunks, weasels, and red fox.


SCREAMERS AND PEOPLE

Though sometimes hunted for food, screamers are more likely to be captured and tamed. They adapt easily to captivity and can be kept with chickens. They walk around freely at South American parks and zoos.


CONSERVATION STATUS

The northern screamer is listed by the IUCN as Near Threatened, at risk of becoming threatened. Although it is not in immediate peril, its numbers have drastically fallen in recent years due to habitat destruction.

HORNED SCREAMER (Anhima cornuta): SPECIES ACCOUNT

Physical characteristics: The horned screamer measures 34 to 37 inches (86 to 94 centimeters) long. Its body is greenish black with a white belly. A "horn" protrudes from its forehead.


Geographic range: Found in the Amazonian regions of Venezuela, the Guianas, Colombia, Ecuador, Peru, Bolivia, and Brazil.


Habitat: The horned screamer lives in wetlands of tropical forests such as lakes, swamps, and marshes. It is found at altitudes up to 3,300 feet (1,100 meters).

Diet: Horned screamers eat aquatic vegetation.


Behavior and reproduction: This bird has a distinctive set of calls that can be heard for miles. It swims or walks on vegetation while feeding, and likes to rest in shrubs and trees rather than on the ground.

Screamers build floating nests of plants and vegetation. The female lays two eggs, which are incubated by both parents. Both parents also care for the young.


Horned screamers and people: These birds are tamed and kept as pets. They are also hunted for their meat.


Conservation status: Horned screamers are not considered to be threatened. ∎

FOR MORE INFORMATION

Books:

Bird, David M. The Bird Almanac: A Guide to Essential Facts and Figures of the World's Birds. Buffalo, NY: Firefly Books, 2004.

Hilty, Steven L. Birds of Venezuela, 2nd ed. Princeton, NJ: Princeton University Press, 2003.

Sibley, David Allen, Chris Elphik, and John B. Dunning, eds. The Sibley Guide to Bird Life and Behavior. New York: Knopf Publishing Group, 2001.


Web sites:

Howard, L. "Anhimidae." Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Anhimidae.html (accessed on June 1, 2004).