Some Birds Follow Moving Swarms of Army Ants in the Tropics

Multiple Choice

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow behind and eat any insects or small vertebrates that had flown jumped away from the moving swarm. Which of the following species interactions does this example demonstrate between the birds and the ants?

A) consumption
B) commensalism
C) parasitism
D) mutualism