Grazing cows disturb the grass and cause insects to fly around the cows as they eat. In turn, birds swoop in and eat the insects. This type of feeding relationship is an example of

The feeding relationship in the first scenario can be considered as commensalism. It is a form of nutritional relationship between two organisms in which one of them, the commensal benefits, and the other is unaffected in any way.

The bird, being the commensal in this case benefits from the cow because without the cow disrupting and driving out the insects, there will not be any food for the birds to feed on. On the other hand, the cow neither benefit nor suffer from the actions of the birds.

The feeding relationship between the birds and the insects is predator/prey relationship. In predation, the predator kills and feeds on the prey. The predator is usually bigger in size than the prey. The predator is usually well adapted and equipped to hunt for its preferred prey in the environment.

In this case, birds are bigger than insects and are able to feed on the insects. This means they posses all the necessary features to pick, eat and digest the insects.

Hence, the answer could be commensalism/predation depending on the point of focus.