The suspension bridge over the Puerto Viejo river at the entrance is the single most productive spot on the property. Sunbittern work the rocks below, kingfishers pass under the span, and the trees either side hold toucans, oropendolas and, early and late, howler monkeys.

The paved main trails through primary forest are where the guided walks go: collared peccary, agouti, coatimundi and three monkey species, with poison dart frogs on the leaf litter and the thick understorey growth that fifty years of protection produces.

The old secondary growth and arboretum along the edges hold the best birding on the station. La Selva's bird list runs past 500 species — great green macaw, snowy cotinga, great curassow and a long list of antbirds and hummingbirds among them.

The night walk is essential here: red-eyed tree frogs, glass frogs, eyelash vipers, kinkajou and a fully different set of insects. Guided night walks are limited in number and should be booked when you book the room.

The drier months from February to April and September to October make trails easier, but this is Caribbean lowland rainforest and rain falls in every month.

Practicalities

La Selva is near Puerto Viejo de Sarapiquí, around two hours from San José. Accommodation is simple station housing and the food is canteen-style; the guides are the reason to come.

Day visits are possible but you will miss dawn and dusk, which is when the forest works. Booking direct with the station supports the research; be aware that trail access is sometimes restricted where studies are running.