Horned Screamer (Anhima cornuta)

About Horned Screamer (Anhima cornuta)

• Kingdom: Animals
• Phylum: Chordates
• Class: Birds
• Order: Anseriformes
• Family: Screamers

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 in Anhima cornuta. “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.

Mating System: monogamous

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. Anhima cornuta individuals build 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. The eggs average 84 mm in length and weigh an average of 150 grams.

Breeding interval: Horned screamers breed continuously throughout the year, the interval of egg laying is not known and may depend on available nutrition for females.

Breeding season: Screamers breed during any season.

Range eggs per season: 2 to 8.

Average eggs per season: 3.

Range time to hatching: 40 to 47 days.

Range fledging age: 60 to 75 days.

Average time to independence: 1 years.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; oviparous

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.

Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Protecting: Male, Female); pre-independence (Protecting: Male, Female)

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