system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do messenger pigeons work?
gpt
You raise pigeons at the *destination.* You let them roost, and fly for exercise. They see this as their home.

When you go out campaigning, you take some of these birds in cages. You don't let them fly, or they will just go home.

When you want to send a message, you tie it to a bird's leg, and then set the bird free. The bird just goes home.