Visual Signals in the Crepuscular Common Nighthawk (Chordeiles minor)

Abstract

The common nighthawk (Chordeiles minor) is a crepuscular species known to use visual signals for agonistic and sexual communication. To test the hypothesis that white plumage patches function in visual communication of reproductive quality, we measured the size of white patches present on the wing, tail and throat of the otherwise cryptic plumage of males of this species belonging to three age classes. There was a significant increase in wing-band and tail-band size with age, but no significant increase in throat-patch size. We argue that these white patches, combined with behavioral displays, likely function as visual signals of male quality.