The senses of predators are adapted in a variety of ways to facilitate hunting behaviour. Visual acuity is great in raptors such as the red-tailed hawk, which soars on high searching for prey. Even on a dark night owls (owl) can hear, and focus on, the rustling sound and movement of a mouse. Many insect-eating bats (bat) hunt by echolocation, emitting a pulsed, high-frequency sound—in the manner of a ship's sonar—while flying; the sensory data thus gained guides them to their prey. A flock of white pelicans will cooperate to form a semicircle and, with much flapping of wings, drive fish into shallow water where they are easily captured.