Diving bird

Today, cormorants (family Phalacrocoracidae), loons (Gaviidae), and grebes (Podicipedidae) are the major groups of foot-propelled diving birds.

Their neck muscle will contract during the impact process, and the tendons will apply tension to the bones as a stabilizing force during the dive.

Different shapes of a bird's wing are important in determining the flight capabilities; they can affect aerodynamic performance and maneuverability.

[10][circular reference] In the fully open condition, the morphing wing reaches the maximum surface area and has a 32% higher lift coefficient which to achieve high maneuverability at low speed.

In the fully closed condition, the morphing wing would minimize the surface area and reduce the drag coefficient by 29.3%, from 0.027 to 0.021, to achieve high-speed flight.