Birds are similar to planes, they have the same factors affecting them, drag, thrust, lift, and weight. In planes, we use jet engines to overcome drag and produce more thrust, while birds use their wings to produce thrust. Birds, using their wing push the air below as it flaps down, and create a high-pressure area below and a low-pressure area above, which then leads to generating lift. But as they flaw up they turn their wings to the back, basically pushing the compressed air behind, leading to thrust.

• The more surface area the wing has, the more air it will push down, which means at certain points birds like macaws and hawks, create such low-pressure areas above them that it alone pulls them up, Like the vacuum effect in cars.

• There is a double factor of lift possible in birds like parrots, it is only a conception, but while observing them, ornithologists have found that as they push the compressed air behind, they also direct some under, creating a little thrust from below resulting in better lift.