A pair of Canadian geese decided my pasture was a good a place as any to set up home, which would be fine except they're vicious little buggers. My arena is unfenced and open onto the field, they haven't bothered me or my sister while riding (yet) but I was walking through the arena the other day and they started running at my friend and I in full on attack mode, when we started running they went into flight and did end up leaving us alone, once the horses were between us and them.
Oh and I go out today and there are six of them out there. Six geese on our field. A few years ago I saw a goose leave a dog needing 50 stitches. Ugh.