We took a boat tour of the Rio Frio (as close as we could get to Caño Negro in one day from La Fortuna) and saw a number of different birds, including a large number of what I believe to be Ringed Kingfishers (our guide said they were green kingfishers, but all the identification photos I can find of those show them as having a much greener colour). This one was perched and possessed of a large lunch for such a small bird.