Experimental set-up in front of the dam wall (Olef-Talsperre, Hellenthal, Germany).

<p>The two cameras of the stereo system were positioned opposite, separated by a river leaving the dam wall. The features, displayed on the wall enabled us to calibrate the stereo camera system and to exactly determine the position of the diving falcon in the images of both cameras.</p

Velocity magnitude (A) and acceleration (B) of the falcon during the time pathway flight.

<p>Spline interpolation of the data with the aid of a moving 3^rd-order-polynomial approximation.</p

Forces acting at the falcon during diving at maximum speed and zero acceleration.

<p>For the given flight path angle θ only one angle of attack α leads to the fulfilled condition of equilibrium.</p

Force balances error.

<p>Force balances error.</p

Reference areas of the falcon model.

<p>Reference areas of the falcon model.</p

Flow visualization on the surface of the falcon model via oil-based painting.

<p><b>A:</b> top-view, <b>B:</b> frontal side-view. (Re = 5.8 10⁵, angle of attack α = 5°, flow direction is from left to right).</p

Wind tunnel specifications.

<p>Wind tunnel specifications.</p

Lift and drag coefficients for a parallel direction of flow (α = 0°) and an angle of attack α = 5° for a velocity of 22.5 m s-1.

<p>Lift and drag coefficients for a parallel direction of flow (α = 0°) and an angle of attack α = 5° for a velocity of 22.5 m s-1.</p

Detail studies for the specific wing shapes.

<p>Detail studies for the specific wing shapes.</p

Variation of flight path angle θ in the major tracking phase.

<p>The bird starts from almost vertical flight (θ = 90° relative to the horizontal) and still had a flight path angle of θ = 70° when it entered the tracking area (t = 0). The light path angle decreased then continuously until the bird pulled out (θ = 0°) at 2.3 s. The flight path angle is about 50.75° when the bird reached the maximum velocity.</p