Flight
One of the most important defenses a bird has is flight --- taking to the air to escape predators. However, flight isn't always the best defense from other flighted predators, like hawks and owls. Skilled, evasive flight is key to surviving attacks from raptors. While aerial flight is not an option for birds like penguins and ostriches, these species have adapted to be able to swim or run quickly to escape danger.
Fight
If a bird is unable to fly away or is protecting its young, aggressive methods of defense are used. Diving and pecking with tough beaks and using claws to attack predators is one method birds have of driving animals away. Small birds sometimes use a technique called "mobbing." Mobbing means the birds surround a predator and call incessantly from nearby branches and shrubs, hoping to confuse the animal. The cassowary, native to Australia, is considered the world's most dangerous bird because it uses its 4-inch, daggerlike claws to attack threatening animals, even humans.
Fooling
Some birds seek to prevent confrontations with predators and use several defensive methods to escape detection or distract threatening animals. Natural feather coloring that allows the animal to blend into its habitat --- camouflage --- is one way of escaping detection from predators. Another way to distract a dangerous animal from defenseless nests or young is for the adult birds to pretend they are injured and lure the predator away from the area. The killdeer is known for its fake broken-wing display, and the bird also sometimes pretends to brood on a false nest.
Unusual
Birds found throughout the world have truly unique ways of protecting themselves and their young. When threatened, the fulmar chick vomits an irritating oil onto predators. The foul-smelling, bright-orange substance coats the animal's fur or feathers and causes it to mat and lose its insulating qualities. Burrowing owl chicks make a hissing noise similar to that of a rattlesnake when threatened. The hooded pitohui of New Guinea is actually poisonous --- it eats certain beetles that possess a toxin just like that of poison arrow frogs. Touching one of these brightly colored birds may cause numbness and tingling, and eating one could result in serious illness or death.