Great potoos have relatively large heads in relation to their bodies. They have large eyes with a light brown to yellow iris and beaks that are short but broad, giving them a very large gape. In comparison to other Caprimulgiformes, the facial bristles are diminished to non-existent. They have elliptical wings with an elongate tail that aides in steering during noiseless landings on tree branches. The plumage is white to grayish with marbled black and burgundy tones. Tail coloration matches that of the body, with the exception of the 8 or 9 white bars that extend laterally across it. (Borerro, 1974; Grzmek, 2002; Land and Schultz, 1963)
- Land, H., W. Schultz. 1963. A proposed subspecies of the Great Potoo, Nyctibius grandis. Auk, 80: 195-196.
- Borerro, J. 1974. Notes on the structure of upper eyelid of potoos.. The Condor, 76: 210-211.