For about a week now my cat has been meeting his cat friend in my back garden when it gets dark. They stand about 4 foot apart, facing each other and start caterwauling. The only other time I’ve heard my cat do this was when he fell off the roof and hurt his paw but he’s definitely not hurt. Him and his mate are both neutered males, they don’t seem to be being aggressive towards each other - no tail swishing, hissing or fluffed up backs/ tails. They just stand opposite each other and scream until I go and carry him in, still screaming. Then, once he’s inside, he stops and just goes about his normal business.
I’m more concerned about the noise as we live in a built up area with lots of families with young kids and the cats are just ridiculously loud. I’ve tried keeping him in but then his cat friend kept bashing the cat flap and screaming through that instead.