I awoke to an unearthly din, like a rubber foot pump with hiccups. It was so loud that I could feel it resonating in my guts. In the glass of water by my bed, I swear I saw concentric ripples à la that scene in Jurassic Park.
Peering out of the window of the eco-lodge where I was staying in the Pantanal, South America’s vast tropical wetland, a pair of the weirdest birds met my gaze. Reminiscent of large, satanic turkeys, they seemed to fancy each other, as they bowed and honked and honked… and honked. Was this a love song of sorts? These peculiar birds were horned screamers (Anhima cornuta). And it turns out they are not just odd on the outside but on the inside, too.
What is a horned screamer?
The horned screamer is the weirdest of the screamer bird species – an enigma, like an ornithological unicorn. The hard-to-miss protuberance on its head sticks out at about 45 degrees and gives it its common English name.
What is it also known as?
The ability to fill the air with its unmissable presence has given the horned screamer iconic status – it is called el clon-clon in Ecuador (an onomatopoeic name tag reflecting its call) and Arauca in Colombia, where it is the totem species of the municipality of Arauca.
How many species of screamers are there?
Screamers are a family of three species – the southern, northern and horned. They are all a bit odd. They stand apart from their nearest relatives, ducks and geese, and by looking at them you would never guess their evolutionary kinship.
For a start, there is no ‘duck bill’ but a robust, hooked one, reminiscent of a heavy game bird rather than a goose. They also have only rudimentary webbing at the base of their toes. This doesn’t stop them from occasionally taking to the water, where they are good swimmers.
What habitats are horned screamers found in?
Horned screamers favour wet grasslands and are never far from shallow water – heavily vegetated swamps and lake edges are their domain.
What's weird about the horned screamer?
The horned screamer's long, thin ‘horn’ is neither feather nor bone but cartilage. Despite giving the bird a menacing appearance in photos, in reality, when you see it wobble as the bird moves its head from side to side, it’s obvious that it isn’t much use as a weapon. Only loosely attached to the bird’s skull, the horn’s sole purpose is display. It rarely gets more than 10cm long because, during the wear and tear of everyday activities, the tip breaks off. Watching a pair of birds, it appears they are ‘air jousting’ at times as they go about their head-bobbing, preening and posturing.
Any other odd features?
Another odd external feature of this bird is its spurs. Unlike its headgear, these sharp, bony spikes are effective weapons. They are not on the legs or feet, rather on the wings. Each wristbone brandishes a pair of these spikes, one longer and sturdier than the other. These armaments are most impressive in the males, with the long ‘spur’ often reaching around 6cm in length. It is thought that they are used to defend the bird’s nest and territory.
Why are the screamer's bones hollow?
The screamer also has hollow bones and a unique system of air pockets under the skin. Nobody really knows why this is. Some have hypothesised that it makes the bird lighter or is used to make certain social sounds or ‘sonations’ – intimate, low-frequency calls between mates. For their size, they have some of the lightest and most pneumatic bones in the avian world. Most of their skeleton comprises a honeycomb-like system of air chambers, allowing the birds to soar long distances with ease.
What noises do horned screamers make?
Horned screamers make a sort of honking nose, akin to a rubber foot pump with hiccups. At the other end of the sound spectrum to their big voice, screamers are known to make a peculiar crackling noise when they move. Like the sound of bubble wrap when you scrunch it in your hand, the sound is thought to be caused by the air pockets in the skin collapsing.
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Main image credit: Getty
