http://en.wikipedia.org/wiki/Canada_Goose
Some information on sub-species. The Canada Giant were thought at one point to beextent in the 1950's, until early 1960's. Then they discovered a number of viable flocks that stay nearly year around on the water kept open by a power plant by Rochester, MN (Mayo Clinic).
There were refugees established to help insure those flocks grew and a great many of those Giants in various parts of the country are as a result of those efforts. See the story here:
http://www.avianweb.com/canadageese.html
So, when we are layingout in a picked field near daybreak with the decoys around calling in the Giants coming into a wind, remember to thank those that made that discovery and acted to get them the habitat and protection to recover. Now we can hunt them once again.