Most birds are extremely light and efficient. Their bones have evolved to be light weight to help with this. Some species even fly in a V formation to conserve energy.

Evolution doesn’t mean get better or smarter. It just means the species can survive and keep reproducing. Emperor Penguins in Antarctica for example, where they nest in a place where there are no predators. It seems insane the hardship and their silly walk which takes forever. But it works.