The deer runs through the fields of plants in the bird plant hitches a ride to spread its seed across the field the deer does not mind is it predation, competition, parasitism, commensalism, mutualism
This scenario would likely be classified as mutualism, as the bird benefits by getting a free ride to spread its seeds while the deer does not necessarily experience harm or benefit from the interaction. Both species are able to benefit from each other's actions in this situation.
