Get the peck out!
The impala and the ox-pecker share a symbiotic relationship. Ox-peckers eat ticks, blood-sucking parasites, fleas, and lice off the impalas. This helps the impalas getting harmful parasites off of themselves. And the peckers get their happy meals. However, recent studies suggest that the two are not entirely equal partners, and that the relationship is tipped in favour of the peckers.