New Scientist has a story on how peregrine falcons rely on a sailors' trick to hunt down their prey. The video is like watching one of those World War II dogfighting films.

[Falcons] fixed a potential victim in their field of view using a method commonly used by sailors to avoid collisions, called constant bearing. This meant they were always flying towards the prey's future location, ready to intercept them.

Many other animals, such as bats and dragonflies, also rely on constant bearing, which is also a form of camouflage: by keeping prey steady in their visual field, the predator also hides its own motion from the prey's view.