Here is one of the many bullfrogs who lives in the corner of the lake where several herons hunt for lunch.
I was able to observe several frogs floating in the water until a woman walked past with her off leash dog. The dog ran into the water and all of the frogs swam under water and the heron flew off.
It seems many dog owners don't care that people like to observe nature and that wild life doesn't exist purely for their off leash dogs' entertainment. (There is a 6 foot leash law in this particular park and only about half of the dog owners I see observe it.)