Swallows.
When birds fly south for winter each year, this is known as "migration." The birds fly south to live in a warmer climate, and in the spring they fly north again when the weather changes.
They wait for the birds to return.
It is not only birds that fly. Bats fly and they are not birds.
3-19-2011
Migratory birds fly south during autumn and return north in spring.
Sience 1910
Most birds can fly. Not all.
To say that birds use wings and feathers to fly, so all birds can fly, would be false. Not all birds can fly. An ostrich is an example of a bird that cannot fly.
The birds that can fly because it is easier for them to find food.
all birds fly xept penguins
There is no such thing as a dinosaur that flys. The difference between a pteradoctyl and a bird is: Birds have feathers and pteradoctyl's don't. The difference between a oviraptor and a bird is: Oviraptor have hands and birds have wings.
Birds fly, fish swim