because it is cold
The main reason that birds fly south in the winter is because they can't stay in a cold place so they fly south to a warmer place during the winter.
When birds fly South for the winter it is called migration.
yes they do
Birds survive in the winter by migrating south for the winter to stay warm when spring comes around they migrate back.
Monarch Butterflies. They fly south for the winter like birds do.
Most animals hibernate in the winter but birds head south.
They don't stay when it is snowing. Hasn't anybody learned that birds fly south in the winter?
migration
flying south during the winter
migration
Migration
The blue birds flew south for the winter.