Any member of the order Falconiformes (eagles, falcons, hawks, and vultures) or Strigiformes (owls). Falconiforms are also called raptors. They are active during the day, whereas owls are nocturnal. Condors and eagles are among the largest and strongest of flying birds. All birds of prey have a hook-tipped beak and sharp curved claws called talons. (Nonpredatory vultures have less-developed talons.) Despite the similarities between owls and raptors, many authorities believe they are not closely related but developed similar features because of their similar predatory lives.