This pond was full of small, young American Bullfrogs. I had to double check my book to make sure I didn't mistake this for a Green Frog. Interestingly, my book mentioned that American Bullfrogs skip across the water before diving when alarmed while Green Frogs dive directly under the water without skipping, something I didn't know. Skipping across the water before diving is what I observed these little American Bullfrogs doing as I walked along the edge of the pond.