Red-billed oxpeckers travel around on herd animals and eat ticks and parasites living on herd animal's skin. the birds get food, and the herd animals get pest control. Is it commensalism, mutualism, parasitism, or predation?

The relationship described between red-billed oxpeckers and herd animals is a mutualistic relationship. Mutualism is a type of symbiotic relationship in which both species involved benefit from the association. In this case, the red-billed oxpeckers get food by consuming ticks and parasites living on the herd animals' skin, while the herd animals benefit from the removal of these pests, contributing to their overall health and well-being.