What birds have taught us in aviation

People have always studied and observed birds for their ability to fly. Modern airplanes use the same idea to take off. But, maybe there are other ideas we can take from birds.
Interesting Engineering

When birds take off, they raise their wings thereby creating a low pressure, and the body goes up through the process of lift. Airplanes use the same idea when taking off and landing. The scientists mimic the movements of the birds while modeling the wings.Most modern airplanes have fixed wings that cannot change in angles.

However, these planes have flaps on the wings that move up and down depending on where the plane is. The developments on a plane wing are the flaps and ailerons. Scientists are working on a wing that morphs and has more motion similar to that of a bird.

Along with changing how the wing works, research has been conducted in how the wing is formed internally and this research could contribute to using less fuel per flight.

Could there be even more useful technology to be copied from birds?