Many birds make long migrations and often come back to the same area many months later. I am frequently asked how birds manage to find their way around the world, so in this article, I wanted to outline some of the ways that birds navigate.
Birds have an internal compass that they use to orientate themselves. They also use celestial bodies including the sun, stars, and moon to navigate. Birds have a great memory and planetary winds and visual landmarks help birds find their way. Birds also use their sense of smell and infrasound hearing to migrate long distances.
If you want to know more about how birds navigate, please read on.
Orientation and navigation
To understand how birds navigate, we need to understand that they need to be able to find their way first. Orientation is the method of finding a direction such as north, south, east, and west.
Most birds understand how to orientate themselves, which seems instinctive to them.
Once they have oriented themselves, birds need to navigate their route. Navigation involves making or following a route to their destination. Without orienting themselves, navigation would be useless to them, so both are needed.
Navigation is a learned ability that birds learn through experience.
While we mainly use magnetic compasses to orientate and help us navigate, birds use different types, including the sun, stars, and the wind. By using these, birds can tell which way is north.
There are a few different techniques that birds use to orientate and help them navigate to their final destination, which are explained below.
Birds have a magnetic compass which they use to orientate themselves. There are a few different theories where this is located. It is called the magnetoreceptor and is found somewhere in the birds head. Some scientists believe it to be located at the back of the eye, while researchers at Oxford University believe it is a molecule in the bird’s retina.
Some birds, such as pigeons, are known to have a small amount of magnetite on their beaks. Magnetite, also known as lodestone, is a magnetic iron oxide. It is believed that as the bird moves its head, the iron moves through the Earths magnetic field. This causes pressure on the magnetite, allowing the bird to navigate.
The sun is used by birds that navigate during the day. The sun comes out every day and is a perfect instrument to help birds navigate. As the sun rises from the east and sets in the west, birds can orientate themselves early in the day.
Birds are very accurate when trying to find directions, and it is thought that they rely on the shadows the sun casts rather than the sun itself.
The sun helps the birds know what time it is and their orientation. Many birds can see ultraviolet, so even in conditions where clouds obscure the sun, they can still use the sun to navigate.
Birds use planetary winds to help them navigate the globe. Planetary winds are permanent winds controlled by pressure belts, blowing in the same direction all year.
There are three types of planetary winds, the Trade Winds, the Westerlies, and the Easterlies. Depending on where the birds are, they can use one of these three permanent winds to navigate, allowing them to know when to stop, start or turn.
Birds will memorise different landmarks while travelling. They use hills, woods, cities, rock formations, individual trees, and mountains which all have their own shape and look. Water is an excellent landmark for birds, and rivers, coasts, wetlands, and lakes are all amazing geographical features to aid navigation.
This is no different to how we memorise areas when we are travelling, knowing where we are when we have been to the place before.
Birds that rely more on visual landmarks often do better during the day than at night, but there is evidence that they still use visible landmarks at night.
While orientation is instinctive in birds, navigation is learned. Birds can only use visual landmarks, the sun, stars, moon, and planetary winds once they have experienced and remembered them.
Without observing and experiencing the celestial bodies, they would not give any assistance in navigation. However, by watching experienced birds and following them, they can memorise the routes and how they navigate.
Sound and smell
Birds have excellent hearing and can hear low frequencies, called infrasound. Many geographical landmarks give off infrasound as the air passes over them. Coastlines and mountain ranges all produce infrasound. Birds will memorise these locations to help them navigate in the future.
Smell plays a part in memorising routes. Birds that are unable to smell are less able to navigate than birds with a good sense of smell. By detecting and recognising different scents, birds can memorise where these are. For example, a factory that produces peppermint sweets can be smelled some distance away and recognisable landmarks for migrating birds.
Birds use all of the above to get enough information to orientate themselves and navigate where they need to go. Not all birds rely on the same senses to navigate, but using a combination of these, they can fly extremely long distances back to the same pond or forest from which they originated.
Birds travel across the countryside using visual landmarks along with infrasound and smells. They then use their internal magnetic field, the Earths magnetic field, or the sun, stars, and moon to orient themselves before travelling on.
Because weather and environmental conditions can differ between migrations, birds need to use many of the above ways to navigate. If the weather is too bad, for example, they may not rely on geographical locations to guide them, instead using the planetary winds to help them.