I always thought those birds that sit on mammals in Africa were friendly, helpful little things. So today I thought I’d write about them, and end up with a cheerful blog post about multiple species of animals working together and benefiting from their association. The truth is much more sinister, and I am a little disappointed to find out what kind of bird oxpeckers really are.
There are only two species of oxpecker, the red-billed and yellow-billed, which together make up the family Buphagidae. They are related to starlings and mockingbirds, but taxonomists disagree as to how closely. You can find oxpeckers in sub-Saharan Africa, in the east and south of the continent. They are usually found in open habitats, avoiding deserts and rainforests.
The two species of oxpecker look quite similar, though as you may’ve guessed, their bills are different colours. Red-billed oxpeckers have completely red bills, with yellow-billed birds have yellow bills (I know, what a surprise) with red tips. Both species are about 20 cm long, with plain brown bodies.
Oxpeckers are known for hitching rides on large mammals, such as cattle, wildebeests and zebras. Oxpeckers have preferences for certain species, and avoid others. Which species the birds favour is likely determined by how many ticks are usually found on their hosts, as these are the oxpeckers’ main source of food.
It was once thought that oxpeckers and the mammals they feed on shared a mutualistic relationship — the oxpeckers fed on ticks and other ectoparasites, while the mammals benefitted from having personal parasite cleaners riding on them. This may not be the case, because while oxpeckers eat lots of ticks, their favourite food is blood. Ticks are a source of blood, but not the most direct one. Oxpeckers will widen existing wounds on animals, or create new ones, just to get to that sweet, fresh blood. So although they can eat up 100 engorged ticks a day, there is no evidence that oxpeckers significantly reduce parasite loads on their hosts, and the damage they do may offset any benefit they may give.
Oxpeckers are friendly to other members of their species, forming flocks when they are not feeding. They roost on their host animals at night, which doesn’t seem to bother the mammals too much. Oxpeckers also use their hosts during the breeding season, lining their nests with mammal hair. They nest in tree holes, and lay 2-5 eggs in their nests.
If I were a large hoofed mammal, I wouldn’t let any bloodsucking oxpeckers near me, but mammals do; generally they tolerate oxpeckers quite readily. Perhaps they’d rather not have the birds around, but can’t get rid of them and so just accept them as a necessary annoyance. Still, oxpeckers are way creepier than I thought they were.
Cover image credit: Lip Kee Yap via Wikipedia