Out in my neck of the woods, these two: Golden Eagle. Courtesy of The American Eagle Foundation
And the Great Blue Heron. Courtesy of Scientific American:
These two theropods are two of the largest, nastiest predators in my local ecosystem. But they avoid each other because they are both very much aware that they are completely capable of killing one another bloodily and relatively easily.
And that’s saying something…..there’s not much on this planet that can kill a Golden Eagle, but a Great Blue Heron is one of those few animals that can. I heard a story from my local Audubon Society where they found a Golden Eagle and a Great Blue Heron dead together. Apparently, the Golden Eagle tried to prey upon the Great Blue Heron and it did manage to grab the Great Blue Heron and fly off with it.
However, as the Great Blue Heron was dying in the Golden Eagle’s talons, it used the last of its life and its very large, sharp beak to rip open the Golden Eagle’s midsection! The two birds then crash-landed and died together, where they were later found by birdwatchers after they had been dead for a bit. If I’m remembering correctly, a couple of hovering Turkey Vultures clued the birdwatchers into the location of the intertwined and very bloody corpses. And this is why these two predators typically take great pains to avoid each other. They’re pretty evenly matched, and they both know it.