Nick Carne
If you want a good example of the value of local indigenous knowledge, read on.
In the Swahili language, Africa’s red-billed oxpecker (Buphagus erythrorhynchus) is known as Askari wa kifaru or “the rhino’s guard” – and now researchers from Australia and the US have shown just how accurate that is.
By tracking wild black rhinos – some tagged, others not – they found that those with oxpeckers perched on their backs were far better at avoiding approaching humans than those without hitchhikers.
The rhinos simply listen for the birds’ warning calls. In return, the birds feed on ticks and lesions on their bodies.
“Although black rhinos have large, rapier-like horns and a thick hide, they are as blind as a bat,” says behavioural ecologist Roan Plotz from Australia’s Victoria University, the co-author of a paper in the journal Current Biology.
“If the conditions are right, a hunter could walk within five metres of one, as long as they are downwind.”
But in a series of trials Roan led with Wayne Linklater from California State University, US, an estimated 40-50% of all possible black rhino encounters were thwarted by the presence of B. erythrorhynchus.
When a rhino picked up the birds’ alarm calls, it nearly always re-oriented itself to face downwind – it’s most vulnerable position as it cannot smell predators from that direction.
“Our experiment found that rhinos without oxpeckers detected a human approaching only 23% of the time. Due to the bird’s alarm call, those with oxpeckers detected the approaching human in 100% of our trials and at an average distance of 61 metres – nearly four times further than when rhinos were alone,” Roan says.
“In fact, the more oxpeckers the rhino carried, the greater the distance at which a human was detected.”
The problem now, Plotz says, is that there are far fewer of them. Just as rhinos have been hunted to the brink of extinction, populations of oxpeckers also have declined significantly – becoming locally extinct in some areas.
As a result, most wild black rhino populations now live without the birds in their environment. All of which points to the value of reintroducing them, he adds.
“While we do not know that reintroducing the birds would significantly reduce hunting impacts, we do know oxpeckers would help rhinos evade detection, which on its own is a great benefit.”