Red-billed oxpeckers on an impala in Mpumalanga, South Africa

The red-billed oxpecker is native to Africa. The birds enjoy eating parasites like ticks that gather on impalas and other hoofed animals. The behaviour of oxpeckers towards these big mammals was previously thought to be an example of mutualism – a relationship that benefits both species. But since the 1990s, some studies have suggested oxpeckers prefer ticks that are already full of blood, meaning by the time the birds eat the ticks, the parasite's damage has been done. So is the oxpecker a friend or foe to its larger mammal hosts? We’ll let you decide.
© Heini Wehrle/Minden Pictures