How can bernoulli's principle keep a bird in the air?

in a steady flow, the sum of all forms of mechanical energy in a fluid along a streamline is the same at all points on that streamline. if the air flowing past the top surface of a wing is moving faster than the air flowing past the bottom surface, then Bernoulli's principle implies that the pressure on the surfaces of the wing will be lower above than below. thus allowing the pressure below to push up on the wing, thus generating lift.