Explain · Like I'm five version
Bird migration in terms of the M25 on a bank holiday
Why do birds fly all the way across the world just to end up in the exact same spot as last year?
Bird migration is like a giant traffic jam on the M25 during a bank holiday weekend. All the birds decide to leave at the same time because the weather gets too cold, just like everyone leaves London to go to the beach when the sun finally comes out. They follow long, invisible paths in the sky that work exactly like lanes on a motorway. The younger birds follow the older birds, just like a family car keeps close to the caravan in front so they do not lose their way to the coast.
It is a very busy trip with lots of stops along the way for snacks and a quick rest. The birds need to find good places to eat, similar to pulling into a service station for a sausage roll and a drink of water. Some birds fly thousands of miles without stopping for a kip, which is a bit like a driver who refuses to pull over despite everyone else in the back seat screaming that they need the toilet. It is noisy, crowded, and takes a very long time.
When they finally reach their destination, the birds do not stay for long before they have to turn around and do it all over again. They seem to enjoy the sunshine for a while, but soon the seasons change and they head back home, just like everyone rushing back to their driveways on a Sunday evening. It is an endless circle of flying, honking, and hoping that nobody has broken down in the fast lane.
Where the analogy breaks downBirds fly in beautiful V-shaped formations to save energy, whereas drivers on the M25 mostly just beep their horns at each other.