Pierre Rabhi is a French author who likes to tell the legend of the hummingbird, which I would tell like this :
Once upon a time an immense forest fire was watched by all the terrified and powerless animals. There was also a tiny hummingbird flying from a small pond to the fire, each time sparkling a few drops into the flame with its beak, and then again and again. The animals cried out “Hey you little fool, it’s not with your drops that you are going to stop the fire!”. To which the hummingbird replied, “Could be, but I do my part”.