Yeah, don't mess with them. They're mean.

One of the trails I rode on in Ohio followed a river, and there was some nice grassy areas on one side. I came around a corner and--GEESE. Geese everywhere. I got off the bike and walked through them. They seem to be less angry and more apt to get out of the way once they figure out what you are. (This was roughly this time of year, though. No babies.)