Is there any way to stop knock door running?

this started a few years ago now and it's on and off during the winter months it's happening, the past few times it's happen over the past two months i've looked out the window to watch where they run off to so i know where at least one of them lives. Also not fully drawing the downstairs curtains doesn't deter them. Is there anything i can do to stop this liking putting a gate up? a 'cctv is in operation' sticker on the door?