This illustration was inspired by a Slavic legend about the water fairies. Water fairies fly to the lake in the form of a swan, and then they take off their swan's suit and dance naked on the surface of the lake. It is said that if a mortal managed to steal the swan suit belonging to a fairy, she would be obliged to marry him. If she ever found her hidden swan attire and put it back on, she would become free again and fly away.
(It is also said that it isn't good fortune to marry a fairy. In any case, if your spouse would run away the minute she had the opportunity, perhaps marriage is not a good idea.)
Today we might interpret this story as an allegory about Nature itself, and how humans treat it. So consider this also a belated Earth Day's greeting from me.