Caño Negro is quite off the beaten path, but worth the effort. Most visits start out at Los Chiles where you board a boat and glide up the Río Frío through canyons of green towards the everglade like Lago Caño Negro. Migration plays a big role in the population of the waterways; you may see a bull sharks fin slice the surface; this area is the end of their annual trip up the Río Nicaragua from the sea, but most people come to spot migratory birds.