Look for white bars at the ends of the wings to distinguish them
Nightjars & Relatives
About a dozen of these mainly nocturnal Spectacled owl birds are found in Costa Rica. At dusk they may be mistaken for bats; look for white bars at the ends of the wings to distinguish them.
The most abundant is the common pauraque (cuyeo; Nyctidromus albicol/is). You might catch sight of one by car headlights at night. During the day, they roost quietly on branch es and flat areas. (I once saw a nightjar sitting in the middle of a hiking trail and it refused to budge even when I stood next to it.) They are camouflaged with a mottled brown, black, and gray, often with a white throat and usually with long bristles around the beak to help them catch insects at night.
Potoos are nightjars found only in the Neotropics. They have a unique camouflage during the day: Instead of sitting horizontally, as most birds do, they adopt a vertical posture and often perch on an exposed tree stump, looking very much like an elongation of it. Your guide gets an extra tip for spotting one. At night, their calls are among the eeriest in the forest. The two Costa Rican species are the great potoo (nictibio grande; Nyctibius grandis) and the common potoo (nictibio común; Nyctibius griseus).