[order] ANSERIFORMES | [family] Anhimidae | [latin] Anhima cornuta | [authority] Linnaeus, 1766 | [UK] Horned Screamer | [FR] Kamichi cornu | [DE] Horn-Wehrvogel | [ES] Chaja Anuma | [NL] Anioema
The Horned Screamer (Anhima cornuta) is a member of a small family of birds, the Anhimidae, which occurs in wetlands of tropical South America. There are three screamer species, the other two being the Southern Screamer and the Northern Screamer in the genus Chauna.
They are related to the ducks, geese and swans, which are in the family Anatidae, but have bills looking more like those of game birds.
Typically, this bird has a grey or black body that fades into a white abdomen. In addition to the abdomen, the wings and crown are also white. The head is small in proportion to the body and has a variety of patterns and colors of plumage. The bill is short with a downward curve and the irises of the eyes are bright orange or yellow. The feathers of the body grow evenly and cover the skin without any bare spaces. Horned screamers have long reddish legs with strong, stout, ash grey feet that lack webbing. The feet lack arches, thus the hind toe is at the same level as the front three on each foot.
Listen to the sound of Horned Screamer
Copyright remark: Most sounds derived from xeno-canto
South America : North, Central
Horned screamers are found in the vicinity of tropical lowland fresh water, such as lakes, ponds, rivers, marshes, and swamps. They often roost in trees and shrubs of wooded river banks and wet savannas.
Horned screamers pair for life, or for at least several years. Pairs stay together throughout the year, seeking isolation in marshy areas in late winter and early spring to trumpet in duets. There are different mating behaviors, ?head bobbing? occurs when one screamer approaches its partner and both birds stretch their necks out and bob their heads up and down one to three times. The main courtship behavior, done all year long, is known as ?social preening.? This occurs when two birds preen the feathers on each other’s necks and heads. Often times there are fights connected with pair formation. Males will use the sharp spurs on their wings as weapons against one another.
Before copulation males walks around females with their bills pressed downward against their inflated crops, neck retracted, and dorsal feathers partially erected. After circling, males will bow their head 1 to 3 times in front of females. During copulation, which takes place on land, males will mount females for ten seconds while grabbing the female’s neck with his bill and flapping both wings slowly.
Horned screamers are year-round breeders with no particular breeding season. When large flocks of non-breeding birds are sighted it suggests that maturation has been delayed for several years. This species builds large nests of plant materials, such as reeds and sticks, that are 8 to 10 centimeters deep. Nests are near or in marshy vegetation in shallow water, typically around eight centimeters deep. Two to eight smooth yellowish-white oval eggs are laid at intervals of 35 to 40 hours by the female. Both parents spend time incubating the eggs.
Horned screamer females usually incubate the eggs during the day, taking short breaks when the male takes over. Males incubate the eggs at night. When the young screamers hatch their eyes are open and they are covered with down. They are nidifugous (young leave the nest immediately after birth) and can run as soon as they are hatched. The young are precocial and follow both parents who offer some food to the young for 60 to 75 days. The parents will also pick up and drop food items in front of the chicks, presumably to encourage feeding.
Horned screamers are mainly herbivorous, eating foliage, grains, and other plant parts. Insects are thought to be a main component of juvenile diet. Screamers graze during mid-morning to late afternoon along grasses and sedges near the water. They peck at leafs, stems, flowers, and vines and graze with lateral head movements. Food is swallowed almost immediately unless the food is longer than the bird’s beak. A less common technique for finding food is digging and filtering through wet mud. Horned screamers rarely drink from their local water source but when they do, they dip their heads in and take large gulps. Their horned tongues allow these birds to manipulate and eat tough plants.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Horned screamers are a native species of the Neotropical region. These non-migratory birds live in a range throughout northern South America that stretches from the Amazonian regions of Venezuela, to the eastern llanos of Columbia, to eastern Bolivia and south-central Brazil. They are now extinct in Trinidad.
Screamers are non-migratory birds that remain within their breeding area all year. Anhima cornuta is a semi-social bird, forming small groups of 5 to 10 individuals, with no conspicuous flocking. They can be seen flying, soaring, swimming, grazing, and roosting in trees. They fly for an average of five seconds and walk for an average of twenty-two seconds at a time.
Title ASPECTS OF THE BIOLOGY OF THE HORNED SCREAMER IN SOUTHWESTERN COLOMBIA
Author(s): LUIS G. NARANJO
Abstract: An isolated population of the Homed Screamer (Anhi..[more]..
Source: Wilson Bull., 98(2), 1986, pp. 243-256
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