Helping the artists

An artist has created a mobile sculpture consisting of two smooth metallic spheres with diameters D=1 m and 2D, connected by a very thin, rigid, horizontal rod, which is mounted on a vertical shaft, so that it can rotate, as shown in the figure below.
a) Determine whether this system will tend to rotate when horizontal wind blows with a speed of 3 m/s; if so, indicate the sense of rotation on a top view.
b) If the surfaces of both spheres become covered with bird droppings, explain any changes to your previous answer.