Birds have several defence mechanisms to protect themselves from danger. Birds normally behave in two ways when they are in trouble, and in this article, we look at how they defend themselves.
Birds deal with danger in two ways. Birds can become aggressive and approach the threat, intimidating the predator into retreating. Birds may also act by withdrawing themselves from the situation. Camouflage, flight, excellent vision, and sharp claws are incredible adaptations that birds use to protect themselves.
For more information on the way that birds defend themselves, please read on.
Why do birds defend differently?
Birds exhibit two behaviours when threatened to protect themselves. They will either become aggressive (apotreptic behaviour) or withdraw (epitreptic behaviour) from the situation.
Adult birds can exhibit both behaviours, but this depends on the species, the threat, and the circumstances. Birds will act and respond to threats differently at different times of the year, such as the breeding season.
As with most animals, birds are most defensive around their young or nests. Because eggs take some time to hatch, birds need to defend their nests until the young can look after themselves.
How birds defend their nests depends on where they are in the breeding process. Early on in the breeding season, such as making the nest, laying the eggs, or in the early days of incubation, birds may abandon their nests if they are threatened.
As the adults have not used too much energy to breed early in the season, they know they will have the energy to reproduce later on.
Later in the breeding season, when their energy and time has been used on their nest, they may be far less likely to give up their nest. However, this will depend on the threat as they will not risk their own lives.
Birds need to weigh up the individual situation and determine if it is worth the energy and the risk. By concentrating on one predator, they may fall foul of another in the area.
Birds will always try to avoid the situation if possible, and their excellent eyesight and colour vision helps them to overcome problems before they become deadly. Birds are constantly on the lookout for danger, and their excellent eyesight can detect even the slightest movements.
A bird’s best defence against a predator is the ability to fly. By flying away, they know they won’t risk injury or death at that moment. Most species have excellent manoeuvrability in flight and can get away from danger quickly, even if it is just to another branch.
Birds that cannot fly may be able to run fast to get away from trouble, but if they can’t then, they may have other ways of defending themselves.
Larger birds such as the Ostrich and Southern Cassowary have large talons on their feet. One kick from one of these birds would be enough to deter a predator quickly if they are still alive. A Cassowary has talons 12cm in length and will jump and strike with its claws. At six feet tall, a Cassowary can disembowel a human easily with its feet.
The most effective aggressive (apotreptic) way birds protect themselves, and their nests is to mob the predator. Mobbing is an effective way to deter even the most determined predator. Mobbing occurs most often in small birds when a predator is active in the area.
Mobbing normally involves all the birds in the area coming together to drive a predator away. The birds will start to dive-bomb and generally annoy the predator, constantly attacking them and making them leave the area. Mobbing is one of the most effective ways that birds defend their territory.
Some species such as the Ostrich, ducks, geese and many passerines try to distract predators from their nest by feigning injury. They pretend that their wing is broken, holding it out to make predators think they are an easy meal. By moving the predator away from the nest, the bird can distract them enough to tire them out so that they retreat.
Many species are very well camouflaged, and this helps them stay safe from predators. Birds use two types of camouflage. When a bird camouflages itself with an inanimate object, for example, a tree that is the same colour, this is called disguise. When a bird imitates another species, this is called mimicry.
Many species blend into their habitat exceptionally well, making them hard to spot among trees or bushes of the same colour. Ground nesting birds will often have a similar colour to the soil or ground in their habitat and will camouflage themselves by concealing themselves against the environment.
Birds can also use disruptive colours to break up their shape. Patterns such as spots or stripes can often be seen on many species, allowing their body shape to become invisible. Many predators do not have colour vision, and disruptive patterns are an excellent defence strategy if the birds do not move.
Mimicking another species is used to give either the appearance or sound of another bird. Some predators will not prey on birds that they think are dangerous, so the predator should leave them alone by imitating one of these birds.
How do birds protect eggs?
Birds build nests to shelter their eggs from harsh weather and protect them from predators. While some make their nests on the branches of trees, others build their nests on the ground.
Ground nesting birds are more likely to face predation as there are more predators on the ground. Ground nests usually are camouflaged or hidden and some species have unique ways of keeping them safe.
Some waders secrete a special oil that protects the eggs from being found by predators that hunt using scent. The oil makes the smell of the eggs weaker so that animals cannot smell them, making them harder to find.
How do chicks survive?
Chicks are almost unable to protect themselves as they don’t have much to defend themselves with. Some predatory species can fight off a small predator, but this is very difficult for most passerines without help from the adult.
Some species show behaviours that can scare off predators, even if they are not dangerous. Predatory birds often have sharp claws and bills that they can use to fight off a small attacker but are not effective against larger animals.
While most chicks can’t defend themselves, Fulmar and Albatross chicks have an extremely good but disgusting deterrent. Fulmars can projectile vomit a horrible smelling fluid at predators, which usually saves them from danger. Albatross do not projectile vomit but will bring up the contents of their stomachs, the foul-smelling odour enough to put off any predators from thinking that they will make a tasty meal.
Hoopoes, Cuckoos, and Coucals secrete a brown fluid from their preen gland when a predator attacks them as well as excreting at the same time.
Which animals eat bird eggs?
Eggs are a nutritious snack for many animals, including other birds, mammals, and reptiles. Stoats, pine martens, foxes, polecats, and rats eat bird eggs straight out of the nest. Fox snakes, corn snakes, and rat snakes are just some snakes that feed on eggs as a large part of their diet.
Many other birds will feed on birds eggs. Members of the Corvidae family such as Crows, Magpies, Rooks, and Jays will search for other birds nest to feed on the eggs, eating them in the nest or carrying them away.
Birds will generally try to protect their eggs, but it depends on how far the predator is willing to go. If a predator is too strong for the birds then they will give up their nest in order to survive and make another.
Birds will not risk their lives for the sake of their nest, knowing that in order to breed again they need to survive.
This does depend on the time of year. Later in the breeding season, when they have used up more energy, they will protect their nests more than earlier on.