Hoatzin, Opisthocomus hoazin

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Roz Wade, Interpretation and Learning Officer, writes:

Working on the new displays for the Museum has introduced me to a whole range of new animals I knew little about before. Always a fan of the quirky, one of my favourites is the Hoatzin, Opisthocomus hoazin. The outward appearance of this bird was enough to spark my interest: its crazy comb of feathers on top of the head; its featherless blue face; its overall rather prehistoric look. But then its biology is even more peculiar.

The Hoatzin is sometimes called the Stinkbird after the manure-like smell produced by their unusual digestive system. This bird is a folivore, a leaf-eater. Leaves are difficult to digest, requiring specialist bacteria to break them down and get at the nutrients and energy they contain. Hoatzins have an expanded crop acting as a fermentation chamber to break down plant tissues. This enlarged crop has consequences for the flight of these birds. There is only space for some pretty small flight muscles to attach to the sternum (breast bone), so they are not strong fliers. They are quite clumsy flying around their Amazon forest home.

The chicks look like they belong in Jurassic Park. They have a pair of claws on the bend in each wing – reminiscent of the claws on the early bird Archaeopteryx. The chicks will jump out of the nest into the river below if a predator attacks, and these claws help them to climb out and back up to the nest.

I’m looking forward to putting this specimen in the new bird display, where I will no longer just walk past it on the way to other animals, but look at it and wonder at its crazy lifestyle and appearance, and hope that with the new labels and interpretation more people can discover and appreciate this wonderful creature.