Looks like deer damage. Could be ground hogs too.

IME deer tend to eat what they remove, while both squirrels and groundhogs tend to leave some of what they have removed behind. You could spray them with something like Deer Off that makes them smell and taste unpleasant. I think it needs to be resprayed after rain, though when I used it on shrubs for the winter, I mixed it with Wiltpruf so that it wouldn't wash off.