oxpecker 
noun
A brown African bird related to the starlings, feeding on parasites that infest the skins of large grazing mammals.
- Genus Buphagus, family Sturnidae (or Buphagidae): two species.
- We were on our second day, descended a hill when we spotted four redbilled oxpeckers riding a white rhino, busily probing folds of skin, ears and even nostrils for ticks, their primary food source.
- The red-billed oxpecker keeps ticks and other vermin from the skin.