An adult Harpy Eagle (Harpia harpyja) attacked and killed an infant collared peccary (Pecari tajacu) at a site in eastern Amazonia. The eagle appeared to have been prevented from removing its prey immediately by surviving members of the peccary herd. Circumstantial evidence suggests that a set of specific factors, including the abundance of peccaries at the site and forest structure, may have facilitated the attack.