The above video is of a mechanical bird that flies simply by flapping its wings. Which contrary to the simplicity of that sentence is something that is very difficult to achieve.
Aerodynamic principal and the lift generated by an airofoil is a topic that we have understood since the mid 1920's.
What makes this "bird" so unique is that it has no power source other than its own wing beats and can land and take off on its own.
Watch the video above to see for yourself how natural the bird looks in flight and how the head and tail move when it turns.