My experience has been much the same as everyone else's. Geese are usually pretty easy going about new additions. I don't do anything special, just go right ahead and release the new bird into the general population and let nature take its course. I have never had new geese exiled to the outer edges for months, though. The longest I've seen is a couple of weeks, the shortest has been just a couple of hours. Usually there's a lot of honking right at first, maybe some hissing and usually if it's a new gander there is a bit of a gander scuffle and then that's that.