Common Potoo (Nyctibius griseus) Science Article 1
The Potoos (Nyctibius) have been studied by various authors, among them Goeldy ( 1896), Haverschmidt (1948, 1958), Borrero (1970), and Skutch (1970). The information presented in this study is based on both day and night observations of two captive and five free-ranging N. griseus (Common Potoo), one N. aethereus (Long-tailed Potoo), and variorls N. grandis ( Great Potoo). Skutch (1970), who has presented the most complete study of Nyctibius griseus, described how, on becoming aware of an observer, the bird slowly lifts its head to a vertical position and simultaneously almost closes its eyes. Only a slight aperture, opened from time to time, is apparent. Haverschmidt (1958) described this same behavior for N. griseus from eastern South America. Recently, I confirmed that this behavior pattern takes 17-23 sec.
JOSfi IGNACIO BORRERO H, The Condor 76:210-240, 1974