It never really occurred to me, but birds learn to fly. They aren't born flying and after they hatch much of their development is learning to fly. They learn by watching their parents and practicing all of the little steps until they master each one. It takes a lot of practice.
What got me thinking about this is an eagle-cam on YouTube https://youtu.be/7RBwjHsW1sk). I've watched as the egg hatched and grew to an almost full grown eaglet in just under three months. E9, as he is known, will soon leave the nest and strike out on his own. I've watched with fascination as he's practiced daily all of the little skills required to fly. Sometimes he'll flap for minutes while balancing on a branch.
In any case, observing the behavior of E9 and his parents has provided a window into their world. Now when I see a bird I have a new appreciation for its early development.
A few days back I went out on a windy day to take some pictures and noticed a flock of gulls by the water. As they flew against the wind they were nearly stationary in their forward motion. That allowed me to capture some gulls in flight with the bridge in the background. They were quite skilled at flying in blustery conditions. And of course they've had plenty of practice.