wings are helpful.
Because:1. They evolved that way2. Some birds have no need for flight3. Bees have wings
some birds are to big for their wings to make them fly
They have bigger bodies and need more power to fly.
Migration of the birds occurs during autumn. The birds fly south prior to winter.
wings
Some birds is light but some birds is heavy . That's why some can fly . I think that's the answer .
They are not defective, but some birds can't fly-for example turkeys & the ostrich.
No. Bats and some insects can fly, and neither are not considered birds.
Normally birds are easily recognizable because they have wings and fly. However, there are some birds which don't fly and some animals that do fly even though they are not birds. Birds that don't fly include ostrich, emu, cassowary and penguin. Animals that fly include bats and flying foxes.
They are different species of birds well ducks fly to sorry SOME kind of duks fly
Not sure what you mean by that, but birds do fly.
so they can fly