What dual purpose do the Kiskadee's loud calls serve during aerial defense?

Answer

Announcing the predator’s presence to nearby potential prey and overwhelming the attacker

The loud calls serve to alert other potential prey about the predator's location and simultaneously irritate or overwhelm the attacking raptor enough to make it depart.

What dual purpose do the Kiskadee's loud calls serve during aerial defense?
birdPredatorKiskadee