My wife & I have a little plastic pond with steep walls and I made a little water fall for it, however twice this year we found a drowned bird in it. They obviously come to drink and fall in & cant get out. does any of you pro pond gurus have any suggestions how I can prevent this from happening. Would floating something or some type of water plants solve this. We have a fountain just 15 foot away from this pond they can safely drink from, but some still fall into the pond.