I think deer are use to all the little woods creatures cats, squirrels, foxes Birds etc. when they are around making noise I think the deer feel safer and they cover up your movements / noise a bit. Just another theory. I hate the noise the squirrels make and they do seem to be gone when the deer show up. A lot of times when the woods is being noisy it gets quiet when the deer arrive so use the silence as a clue to look around Mr buck is here.