Great, and that´s probably why it´s fairly peaceful where you are, as opposed to having a gander.
One of my geese kept me guessing... for a long time I thought she was a gander, until I bought another trio, and discovered she was actually a goose! (The gander was busily mating with her, and...
I would say it´s breeding/territory stuff. And some will think the whole harem is theirs...after all, only 4 geese, right? Did they not have much room?
Then it was made worse by the older gander having the females all to himself, and then suddenly this young male turns up again....almost...