Little is known about the behaviors of Crested Eagle other than nest observations and limited foraging observations.
Foraging behavior has rarely been observed, but prey is seemingly taken while in flight (Julliot 1994). In contrast to Harpy Eagle (Harpia harpyja), Crested Eagle regularly soars, either in pairs or solitary; this is generally assumed to be a foraging behavior (Wetmore 1965, Bierregaard 1994). In two specific instances, Crested Eagle behavior in taking juvenile tamarins has been reported: 1) a tamarin was taken while in flight after the eagle was seen soaring overhead (attack in exposed canopy at height of twenty meters). 2) The tamarin was taken in flight, but the eagle was seen perched about ten meters from the feeding tree before the attack (attack in sub-canopy at height of 13 meters) (Vasquez and Heymann 2001). In other observations, Crested Eagles have often been seen perched on tall roosts for long periods, possibly watching for prey (Bierregaard 1994). Most attacks on prey are in forest interior.