Final answer:
The interaction between dolphins and birds as they both eat mackerel is an example of predation.
Step-by-step explanation:
The interaction between dolphins and birds as they both eat mackerel is an example of predation. In predation, one organism, the predator, feeds on another organism, the prey. Dolphins are the predators in this scenario, as they hunt and consume mackerel, which are the prey. Birds may also eat mackerel, but they are not the main predators in this interaction.