How do geese know which way is south when they migrate?

Question

I know that it is instinct to fly south in the winter. But how do they know which direction to fly? I thought maybe they follow the sun or something, but the sun goes west to east, not north to south. My friend says that it is just engraved in their minds when they are born, but I just don't understand how they can just know which direction they want to head in.

Answer 1

They have a compass inside them. Some bacteria have iron inside them, and these type of bacteria has been found in migrating animals. The iron is attracted by the magnetic north, and so they know which way is north.

Answer 2

Research has shown that birds in general rely on landmarks, stars, and some even have a built-in "compass" inside their brain to follow magnetic north/south. Geese do not seem to have this compass, as they frequently get lost in fog, etc... For geese, the current theory is a combination of following the land and following stars.

Answer 3

The ability to successfully perform long-distance migrations can probably only be fully explained with an accounting for the cognitive ability of the birds to recognize habitats and form crude mental maps.

Monitoring Earth's magnetic field, apparently with their visual system and with tiny grains of a mineral called magnetite in their heads
Observing the stars
Using the sun for guidance
Smell

Answer 4

It's all about the sun. They know it rises in the East and sets in the West.