Pelican flying

American White Pelican (Pelecanus erythrorhynchos).
Ding Darling National Wildlife Refuge, Sanibel Island. January.
Photographer: Peter R. Cavanagh

Lift is a force created by airflow over a wing. It supports the weight of the bird against gravity. Birds do not need to flap to create lift.

Lift increases rapidly with increase in speed in a square-law relationship. This is why larger birds may run on the ground before taking off and why large airplanes have to go so fast in their takeoff rolls.

Lift is not cost-free but is always accompanied by a force called drag that tends to slow the bird down. Evolution has refined the wing design of different bird species to provide them with combinations of lift and drag that favor their life styles.

SPW2 Secondary_IllustrationThe red lines (vectors) show lift forces that are generated by the difference in pressure between the upper and lower surfaces of the wing.  Lift is not constant across the wing section.


KIDS QUESTION: We asked: What opens up from the bottom of a Pelican’s bill?

The answer is: A pouch for catching fish

The lower part of the bill of the American White Pelican is called a gular pouch. It stretches to a large size that can hold 3 gallons of water and is used for collecting fish.