One of our river neighbors keeps a pair of goose decoys by the river, which in turn attracted a pair of Canada geese. The foursome hung out together all summer, so when we'd paddle by we'd always guess which were the real geese.
This picture, taken just a minute or so later makes it clear; did you guess right?
The decoys and geese stayed until October. This shoot is close enough that the plastic eyes are obvious. The real geese are still nearby.
Shortly after that picture was taken the decoys went away, and presumably the real geese did as well.