Papagaios, Life & Times on a Speculative Archipelago

Transcript of video “Island Bird of the Week #24” from YouTube channel BarneyCoolGoose. Video released June 9^th 2018.

[Barney walking towards camera in park]

Ask anyone in this British park about swans and there’s a good chance they’ll say

[Cut to old woman]

“Ooh, they can break your arm”

[Cut back to Barney]

This is, by all accounts a myth, but one that is recited like a mantra by all British people. However, out in the middle of the Atlantic ocean, there lives a bird that is capable of breaking arms and much more.

[Fast successive shots of Papagaios villages, city streets, coast, forest and more]

The Papagaios Islands are a microcosm of the rest of the world, with big urban centres brushing up against jungles and ancient farming villages in the shadow of volcanoes.

My mum’s from here, so I’d spend most of the school holidays at my grandparents’ house in the village of Água da Floresta.

[Slightly grainy home video, dated 4 Aug 1998. A garden with many flowerbeds, bushes, ornaments and ornate metal chairs. An older man slowly walks away from the camera, towards the bushes which are rustling. A woman speaks Portuguese from off camera, subtitle appears “Be careful, Dad.”

The man pokes into the bush with a broom handle then drops it in shock and half-runs, half-scrambles towards the camera. A knee height, heavy-set bird waddles from the bushes.]

This bird is native to most of the big islands of the Papagaios. A member of the burrowing birds known as cavadors. Its scientific name is Eusfinus pankratus, but it is better known by its common name the ‘boxing cavador’. Why does it have that name?

[Cavador wanders the garden, a little confused. It squares up to an ornamental sculpture of a swan, hollers at it, then, noticing the statue does not back down, flicks out its wing which hits the ceramic bird, shattering it.]

That is why.

The boxing cavador is a heavy bird, around 12kg (26lbs). While there are heavier flying birds, the cavador’s foraging and burrowing lifestyle makes flying an unnecessary expense. Instead of using its wings to escape predators, this bird uses the associated muscles and bones to pack quite a wallop – just ask the statue!

[Image of the wing bones of a boxing cavador (upper) and a typical bird (lower).]

To facilitate this, it has several adaptations to its wing anatomy. In general terms, the bones of a boxing cavador’s wings are slightly thicker than those of their nearest relatives, as well as denser having lost some of their pneumaticity. That is to say, they are less hollow.

Furthermore, the bones of the hand are even denser and enlarged than those in the arm, as well as significantly fused, with the metacarpus, basal phalange of the second finger, and the third fingers all fused together into a club-like mass of bone.

When a bird folds its wings, the wrist bends so much that the hand more or less doubles back on itself. This is achieved thanks to the ‘semilunate carpal’ a crescent-shaped bone of the wrist. The boxing cavador is unusual in that it cannot maintain the folded wing position for very long, owing to a particularly tight tendon in the forearm. When the hand is folded back, this tendon stores a lot of potential energy which is released when the bird extends its wing, and magnifies the impact force.

[Clearer, professionally shot footage of a pair of boxing cavadors approaching each other in the forest.

They keep their distance, circling slowly, then approach, stamping their feet.]

This unusual adaptation is extreme and found only in this species, though it appears to have occurred in an extinct relative, as well as the unrelated Jamaican ibis, also now extinct. What pressures could have caused such an adaptation to evolve? As with all cavadors, this species is fossorial, using its wedge-shaped beak with its hardened edge to dig hollows and tunnels, and its large, flat feet to push back loose dirt. The webbing that the bird’s ancestors used to propel them in the water has grown thicker and tougher and aids in turning the feet into shovels. As primarily insectivorous animals, cavadors gain find most of their food by digging, though they also use their tunnels as nurseries and shelter.

Males and females are around the same size and neither sex is aggressive to its own kind. Males win females by stomping their large feet and honking in an absurd dance. They also use this dance in rare territorial displays. Pairs mate for life and spend most of their time in close proximity to aid in foraging and watching for danger.

[A series of short clips. A dog running through the forest, a human on a quadbike in the walnut meadows, a wild pig knocking down vegetation, a cat sneaking through the tall grass.]

Boxing cavadors are large, tough birds with no native predators, though species introduced by humans – and humans themselves – can threaten them. In the past however, the Papagaios islands were home to far more terrifying creatures – giant lizards.

[Fossils of various papagotitans in museums; art work of cavadors and macrocaudates fighting]

Papagotitan lizards come in all shapes and (mostly large) sizes, but the biggest were macrocaudates of genera such as Corneops and Archaeocaudate which clocked in at lengths of 3m and beyond. A slow, plump bird like a boxing cavador would make a filling meal, unless it had a way of defending itself when caught outside its burrows. With the beak and feet already specialised tools, the wings were the only part of the bird’s anatomy that could take on a defensive role.

[Images of fossilised macrocaudate skulls]

It is worth noting, that while a swan cannot break your arm, fossils of ancient papagotitans have been found with cracked skulls, jaws and teeth, showing that taking on a boxing cavador was a risk, and one that could easily end in serious injury or even death. If I had a choice, I’d rather fight a swan.

[Slow-motion replay of the cavador punching and shattering the ornamental swan]