There are several different subspecies of Canada geese. Each from different parts of the country. One subspecies in particular, the one commonly known as the Giant Canada Goose as it tends to be much larger than most other subspecies has been domesticated. These birds, then have gone feral and created non migratory flocks throughout the country. So in many areas, there are both migratory Canada geese which in my area are nearly half the size of the non migratory ones. Occasionally when goose hunting, I see both near each other. The size difference is quite noticeable obviously. In my area, they have an early Sept season which focuses on the non migratory birds which are a real problem. Then they have a normal season where you can hunt the migratory and non migratory birds. They then have a late season where again, you generally are just hunting the non migratory birds.
In your case, you most likely had someone release some geese in your area or over time, a flock of non migratory geese grew in size and spread their range into your area.
