I am not positive, but I believe that the bird on the lower left is a yellow-crowned night heron. I make that identification based on the pattern of the black and white plumage on its head, plus its gray color, size and habitat. The yellow-crowned night heron is more often seen during the day than the black-crowned and other night herons, although they are nevertheless still primarily nocturnal.
The bird in the top right of the photo is a little blue heron ("Little" is part of its name, not an adjective added by me.) They winter in Costa Rica, although some non-breeding pairs remain all year.
Both types of herons shown in this photo live in aquatic areas of both coasts of Costa Rica, particularly in mangroves. We have mangroves in the Tamarindo and Langosta estuaries that border Tamarindo on the north and south, although I took this photo in Tortuguero. The presence of two types of birds so close together in one photo illustrates how easy it is to spot birds in Tortuguero National Park.
Both of these herons are typically 61 cm. (24 in.) in length. The scientific name for yellow-crowned night heron nyctanassa violacea, and for the little blue heron is egretta caerulea.