Years ago, I flew at a field not far from a bay. There were a lot of gulls flying over the field. One day, a guy had an old timer way way up there, floating along at near idle. A little while later, he yelled out. It seems that he thought his plane had rolled over into a steap dive and he had no control! As the "plane" got lower, he realized that he''d been "flying" a seagull for who knows how long, and his plane was long gone.