Bosque de Paz Biological Reserve is a natural biological corridor located in the Continental Divide between the National Poas Volcano Park and the National Juan Castro Blanco Water Park, and therefore has some of the best birdwatching in Costa Rica. The seriously pot-holed road would put off many a casual traveller but it's worth the effort.
I stayed in the lovely 12-room family owned Bosque de Paz Eco Lodge & Reserva Biológica which has the official ranking of Tourist Sustainability Certificate (Certificado de Sostenibilidad Turística C.S.T.) awarded by the Costa Rican Tourism Institute as an acknowledgement for their eco-friendly achievements. There's no TV, no communal facilities and all the electricity is turned off at 9pm so as not to disturb the wildlife. Their nature trails meander through fabulous biodiversity up in the centenarian trees covered in orchids, bromeliads, moss and ferns surrounded by impressive mountains, valleys, rivers and imposing waterfalls.
Mario was my wonderful birding guide, the sons handled guest reception/service and the mother (sadly never seen) cooked the best food I had on the whole trip.
Did I mention it's hummingbird heaven?
And large families of White-nosed Coartis and Central American Agoutis scramble over the lawns, mingling with one of the few places where big groups of Black Guan forage together.