On a serious note: Did you berate the cat? Thats the last thing you should do. Its a weird reverse psychology that cats have going
Mrs Binners recently told me all this, when our cats were doing it. I have no reason to doubt her, as it worked
The cat is bringing you a gift. Hence looking so chuffed with itself. If you berate it, it thinks its displeased you. In its head, its now thinking “he was well pissed off with my measly offering, I need to bring him a bigger one. Or more of the smaller ones! That’ll well impress him!!” Result: shrew armageddon, and your patio becoming the killing fields, with you as an inadvertent Pol Pot
What you should do is elaborately thank him, stroke him, make a fuss of him, tell him the boy done good. Then, satisfied that he’s kept you happy, he won’t bother tomorrow.
Weird things cats