system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do messenger birds know where to go?

Edit: you see it all the time in GOT and other movies. I was watching crouching tiger last night and this dude sent a message with this massive falcon or eagle or whatever...HOW??? I can't even get my dogs to stop dry humping each other when the doorbell rings but these people in medieval and ancient times can teach birds to carry messages thousands of miles over days and weeks to someone just waiting there for them?
gpt
The only real messenger birds are birds that are able to find their way back home, so it's possible to take them with you on a trip elsewhere, then send messages back home on the bird. It won't work in the other direction, however, nor can you send a message to any other random location besides "home".

The reason you see them all the time in GOT and movies is because those are fictional. That also explains the dragons.