Birds
Oxpecker
Buphagus africanus · also called oxpecker, yellow-billed oxpecker, tickbird
The oxpecker is a bird that has almost given up on the ground. It lives on the backs of big African mammals — buffalo, giraffes, rhinos, hippos, cattle — clinging to their hide with hooked claws and a stiff tail, and working through their fur for ticks, dead skin, earwax, and blood. It also acts as a lookout, and its screeching alarm has saved many a short-sighted rhino from an ambush.
Overview
Oxpeckers live in sub-Saharan savanna and grassland wherever herds of large mammals or cattle are found. They are about 20–22 cm long, plain grey-brown, with a stiff spine-tipped tail and sharp curved claws, and a broad flat bill they work sideways through fur like a comb. They eat ticks, botfly larvae, lice, dead skin, earwax, and blood.
A life on another animal’s back
Oxpeckers feed, court, mate, and sometimes sleep while perched on a host, and a large animal may carry a small flock.
The rhino’s sentry
When a predator or person approaches, oxpeckers give a loud hissing alarm. Studies of black rhinos, which see poorly, show that individuals carrying oxpeckers detect and avoid humans far more often than those without.
Helper or hanger-on
Long seen as a pure partnership, the relationship is now viewed as mixed: oxpeckers prefer blood-swollen ticks, keep wounds open to feed on blood, and in some studies do not measurably reduce a host’s tick load.
Status
The oxpecker is Least Concern, common where large hosts are. Chemical tick dips poisoned the birds and removed their food, emptying many ranching areas, with recoveries where farmers changed their methods.
Oxpecker: common questions
Is the oxpecker helpful to the animals it rides, or a parasite?
The honest answer is that it is somewhere in between, and it varies. The classic view is a clean mutualism, in which the bird gets a meal and the host gets pest control and a lookout. Parts of that hold up — oxpeckers do eat large numbers of ticks and other parasites, and their alarm calls genuinely help hosts such as rhinos avoid danger. But research has complicated the picture. Oxpeckers strongly prefer ticks that are already full of the host's blood, they will enlarge and reopen wounds to drink from them, and several studies have failed to find that oxpeckers actually reduce how many ticks an animal carries. So the bird takes real benefits from the host, gives some back, and sometimes does a little harm.
How does an oxpecker stay on a moving, running animal?
With gripping feet and a bracing tail. Its toes end in strong, sharply curved claws that dig into hide and hair, and its tail feathers are stiff with spiny tips, so the bird can prop itself against the host's body the way a woodpecker props against a tree trunk. This lets it hang on the flanks, belly, and even the underside of a host, and work over hard-to-reach places such as inside the ears and around the eyes and nostrils. It rides out a gallop by flattening itself against the animal, and it can hop and scuttle over the body without taking off.
What does an oxpecker's alarm call actually do?
It warns the host. Oxpeckers are alert and constantly scanning while they feed, and when they spot an approaching threat they burst into a loud, rasping, hissing call and often fly up. For a host with poor senses, particularly the black rhino, which has weak eyesight, this is valuable information. A field study fitted rhinos with tracking collars and found that individuals carrying oxpeckers detected people at much greater distances and were far more likely to turn and move away before being seen, compared with rhinos without birds. This early-warning role may be one of the most reliable benefits the oxpecker provides.
Why did oxpeckers vanish from farmland and then come back in places?
The cause was chemical tick control. From the mid twentieth century, cattle across much of Africa were routinely run through dips or sprayed with acaricides to kill ticks, and these chemicals are toxic to oxpeckers, which were also left with far less to eat. In heavily treated ranching regions the birds disappeared. Where attitudes and methods have changed, for example using less toxic products, treating cattle less often, or leaving some untreated, oxpeckers have recolonised, and some conservation-minded ranchers now actively manage their herds to keep the birds around.