Oxpecker
An African bird that rides on cattle and wild animals, eating ticks and other parasites.
Also: tick bird, Buphagus
Oxpeckers are two species of African bird, the red-billed and the yellow-billed, that spend much of their lives perched on large mammals, from buffalo, giraffe and rhino to domestic cattle. They feed on ticks, flies and earwax, and give alarm calls that warn their hosts of danger. The relationship is not purely helpful: oxpeckers also keep wounds open and drink blood, and scientists still debate how much they benefit the animals they ride. Their numbers fell in places where cattle were dipped with chemicals harmful to the birds, and they have returned where gentler tick treatments are used.