Caroni Bird Sanctuary is the classic nature excursion from Port of Spain: a boat ride through mangrove channels where herons, caimans, crabs, and silky anteaters may appear in the shadows. The real reason to come is the evening roost of scarlet ibis, Trinidad and Tobago's national bird.
Go with a guide and aim for the late afternoon departures. The swamp is close to the city but feels far removed from it, and the best moments come quietly as the birds return in flashes of red against the dark mangroves.