Sandhill Crane, Great Blue Huron
Domestic turkeys are bred to be so large that their ability to fly is seriously reduced. See link
It is not only birds that fly. Bats fly and they are not birds.
Flightless birds have a small keel and wings.
Birds have there forelimbs modified into wings to fly. The chest muscles has to be very much stronger in birds to enable them to fly. To bear the force of flying, the sternum in birds has be relatively large as compared to human being.
They feed on fruits, large insects and occasionally small Vertebrates(e.g. lizards).
they can't fly, they are large and they have no wings, obviously! flightless birds include: ostrich, cassowary, emu and penguins!
Smaller birds can fly through the gaps in power lines and bigger birds get stuck when they try to go through.
Birds fly every day. If you have seen a unusually large amount of birds flying, they could be migrating birds passing your area.
No, a rhea can't fly
Mostly to impress female birds. ------------------------------------------------------ Above is BS because even female birds have large breast/chest muscles. Male coloring (plumage) is partly to attract a mate and partly to provide distraction to keep predators from the nest. In order to fly birds must have a broad chest with large breast muscles to pull forcefully on the wings.
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.
Most birds can fly. Not all.