REACTIONS OF WILD TAMARINS, SAGUINUS-MYSTAX AND SAGUINUS-FUSCICOLLIS TO AVIAN PREDATORS

During a field study in northeastern Peru, the reactions of a group of Saguinus mystax on Padre Isla and of a mixed-species troop of S. mystax and Saguinus fuscicollis at the Río Blanco to raptorial and other birds were observed. Alarms that are specific to flying stimuli were elicited by birds of prey, but other birds that do not represent a threat to the tamarins also caused alarm calls. Alarm events (i.e., instances when one or more alarm calls were given) were observed at rates of 0.3/hr (Padre Isla) and 0.5/hr (Río Blanco). Rates of alarm events significantly increased after the birth of an infant in the Padre Isla group and after the attack of an ornate hawk-eagle (Spizaetus ornatus) on the Río Blanco group. Reactions to alarming stimuli/alarm calls ranged from looking up to falling down from trees. The modification of the tamarins' behavior by the potential presence of aerial predators indicates that raptors represent an important predatory threat to tamarins. © 1990 Plenum Publishing Corporation.