Large blackish waterbirds
The olivaceous comorant (cormorán; Palacrocorax olivaceus) and its relative, the anhinga are large blackish waterbirds with long necks and short tails. Both are common in the Tortuguero, Palo Verde and Caño Negro areas but can be found in other lowland regions.
Like the frigatebird, to which they are related, these birds do not have waterproof feathers, yet they are both good swimmers and divers and catch fish underwater. When their plumage becomes waterlogged, they climb into perches and stand with their wings stretched wide to dry in the sun - this is when they are commonly seen. Cormorants have shorter necks and are generally black, though juveniles are a light grey below.