Titanis walleri, the last of the terror birds, has shown the saber-toothed cat Xenosmilus hodsonae who really reigns at the top of the food chain in Florida circa 1.8 million years ago.
The prehistoric terror birds, more properly known as the phorusrhacids, were a family of giant, flightless, and carnivorous cousins of the modern seriema that thrived between 62 and 1.8 million years ago. Most of them would have been endemic to South America, but Titanis is one example that has been found as far north as Texas and Florida. You could say that these big killer birds were among the last of the big predatory theropods.