Mobbing

Little birds like blue tits, woodpeckers and crows repeatedly dive on big birds of prey when they're not in flight to bully them into leaving. Often done to owls who are too sleepy to move away in the daytime. It can stop the chicks being preyed upon, although it takes lots of energy and can attract other predators. Blue tits have a special cry when they see a predator, if the predator is perched the blue tit will let out a call to arms to nearby blue tits and mob the stationary bird. If, however the bird is in flight it presents more of a threat and the blue tit will warn nearby birds with a call called a seet. A seet is a call that is much harder to pinpoint the source so presents less risk of the blue tit being detected

picture by Nigel Barker