Teratorn

The teratorns were a group of very large birds of prey that lived in the Americas from the Oligocene to Pleistocene epochs. They are all extinct now. They include some of the largest known flying birds. So far, at least five species in four genera have been identified:
Teratornithidae are related to New World vultures ("Cathartidae", syn. "Vulturidae").
This group of huge birds lived at a time before mankind reached the Americas in any numbers. The land was more heavily forested than today, and so had herbivores more suited to forests than today. The finds in California suggest that similar conditions existed in much of California and North America west of the mountains.