Migratory birds

Michael and Leon are walking in the forest and they are lost. - Leon, can you give me the compass and the map please? - What map? What compass? - You didn’t bring them? How will we find the camping site now? Maybe these birds can give you some tips. They don’t use a compass or a map to know where to go. - Really?

And where are they going? At the end of summer, the days get shorter, the weather gets colder, and there are fewer insects for the birds to eat. When these changes happen, birds like geese, storks, and willow warblers know that winter is coming. They need to prepare for the long journey to a warmer place. Before the groups of birds set off, each bird needs to gain weight.

This way they can fly longer without stopping. The little willow warbler almost doubles in weight to prepare for 3 days of non-stop flying! Then, the birds are ready to move from the place where they spent the summer to the place where they will spend the winter [...] They are ready to MIGRATE. Flying long distances is hard, especially for large birds like geese. If they fly in a straight line next to each other, they use a lot of energy and need to stop more often.

This is why birds position themselves diagonally behind the bird in front - in the shape of the letter V. When a bird in front flaps its wings, the air moves in a special way. This way, a bird diagonally behind gets a free lift and saves energy! It’s this young Arctic tern’s first migration. It has to fly all the way from the north to the south pole!

It will follow older birds that have migrated before. It will LEARN where the best feeding and resting areas are, and where the destination is. Some birds, like cuckoos, use stars to guide them during their journey. They migrate at night and rest during the day. Other birds, like storks, know where to go based on their surroundings; they follow the shape of the land and use the position of the Sun.

They migrate during the day and rest at night. But what if the environment changes - if a forest is cut down? Or there is now a road through the best field to rest on? Will the birds still find their way? Yes!

The Earth has a magnetic field. This is why a compass needle always points to the north. Birds have a special magnetic material in their eyes, and it works like a compass! They know where north and south are, and can use this to find their way. When spring finally comes to the North, the birds will MIGRATE back home, to enjoy lots of food and nesting spaces available there.

Wouldn’t it be nice to be a migratory bird and avoid winter every year? - Michael, I remember this old tree from last time we were here. I know how to find the camping site! - I guess we don’t need a map and compass after all.