My husband and I booked the 27 May Fincas Naturales night walk and were the only people on the tour. The preserve (aka Manuel Antonio Nature Park and Wildlife Refuge) is across from the Si Como No Hotel. We saw eight species of frogs including: dusty glass frog, gladiator frog, common rain frog, masked tree frog, red eye tree frog, long snouted tree frog, bull frog, and hourglass tree frog. There were red eye tree frogs all over the preserve. We also saw an eyelash pit viper, tarantulas, cane toad and a kinkajou. Our guide, Johnny, was one of the best and enthusiastic tour guides we had in Costa Rica. Would highly recommend this tour.