😳What's that screaming in the back yard?

When you hear bloodcurdling screams from your back yard, you want to know the source. We've been hearing these screeching cat noises for months now, and though we can hear them (and so can the neighbors), no one can see them. Whatever they are. 

But on examining this video, I have a clue - the two placid-looking cats who wander along beside the back fence MIGHT be much more aggressive than they seem. I say this because after a bout of screeching on the right side of the yard, the tabby wandered out, arched its back for a minute, then continued to wander along looking fairly calm. But after that, the black-and-white guy did the same thing. 

THEN, after a few minutes, another bout of screeching broke out - on the LEFT side of the yard this time, where both those cats would be by now. So do they hate each other? Are they mortal enemies and facing off in ungodly feline screams? I hear no actual fighting (and when two cats fight, it's the ugliest cacophany of feral snarls and growls you ever heard), but a lot of the kind of moaning that two tom cats do when facing off. 

So at this point, though it seems highly unlikely, I have no other suspects in the neighborhood except these two local cats who very often stroll through the yard. But never at the same time. The black-and-white now wears a harness which appears to have a GPS on it, so maybe he's prone to roaming, and (as a result) fighting. I always thought the tabby was a girl cat, but I can't be sure. ONE of them is aggressive, and the other won't back down. Or maybe it's some other cat entirely, but I am pretty sure by now it isn't a lynx or a bobcat. Though I DID have the number of the conservation office just in case. Now I'm kind of glad I didn't call, however. . .