"Penguins" joke

A Mexican newspaper reports that bored Royal Air Force pilots
stationed on the Falkland Islands have devised what they consider a
marvelous new game.

Noting that the local penguins are fascinated by airplanes, the
pilots search out a beach where the birds are gathered and fly slowly
along it at the water's edge. Perhaps ten thousand penguins turn
their heads in unison watching the planes go by, and when the pilots
turn around and fly back, the birds turn their heads in the opposite
direction, like spectators at a slow-motion tennis match. Then, the
paper reports, "The pilots fly out to sea and turn directly to the
penguin colony and overfly it.

Heads go up, up, up, and ten thousand penguins fall over gently onto
their backs.