Red-billed oxpeckers’ alarm call may protect black rhinos against poachers
RED-BILLED oxpeckers may help wild black rhinos against poachers by sounding an alarm to potential danger, scientists have said.
About eight inches long with distinct red beaks, these birds are essentially hitchhikers, clinging to big-game animals such as rhinos to remove ticks, flies, and maggots from their hides.
Scientists tracking wild black rhinos found those carrying oxpeckers were far better at avoiding humans than those without the bird.
In a study published in the journal Current Biology, the scientists speculate oxpeckers in
Africa evolved this behaviour as a way to protect their food source.
Study author Dr Roan Plotz, a lecturer and behavioural ecologist at Victoria University, Australia, said: “Rhinos have been hunted by humans for tens of thousands of years, but the species was driven to the brink of extinction over the last 150 years.
“One hypothesis is that oxpeckers have evolved this co-operative relationship with rhinos relatively recently to protect their food source from human overkill.”
Black rhinos are native to eastern and southern Africa.
Classed as “critically endangered” by the International Union for Conservation of Nature, a recent report from the organisation found the black rhino population to be gradually rising at an annual rate of 2.5%.
Despite the increase in numbers, poaching remains a major threat for the animals.
Dr Plotz said: “Although black rhinos have large, rapier-like horns and a thick hide, they are as blind as a bat.
“If the conditions are right, a hunter could walk within five metres of one, as long as they are downwind.”
The team recorded the number of oxpeckers on two groups of rhinos they encountered using radio transmitters to track some of the animals.
Dr Plotz said: “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.
“In fact, the more oxpeckers the rhino carried, the greater the distance at which a human was detected.” The researchers said “40% and 50% of all possible black rhino encounters were thwarted by the presence of oxpeckers” in their experiments.
They add oxpecker populations have declined and become locally extinct in some areas, and suggest that reintroducing the bird back into rhino populations may boost conservation efforts.
Dr Plotz said: “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.”