One group of brown capuchin monkeys (Cebus apella) was observed for 19 months in French Guiana. White Hawks (Leucopternis albicollis) were seen in association with these monkeys throughout the year.
Our study revealed that :
(1) hawks mainly followed capuchins in open forest types, and in this vegetation they mainly flew at the height of 10-20 m from the ground where horizontal visibility is better than in other strata of the forest,
(2) hawks usually landed preceding the monkey troop spreading into an area, and they followed the capuchin troop when the monkeys were traveling, and
(3) no predation of any capuchins by hawks occured at any time during our study, and seven times it was observed that hawks captured arboreal snakes disturbed by the movement of capuchins.
We propose that White Hawks followed brown capuchins in this Amazonian forest primarily for capturing arboreal snakes disturbed by monkey troop movements.