Right, they aren't ducks. Not Canadian Geese either, unless you've seen their passports .
The species is often called the Canadian Goose, but more properly it is the Canada Goose (Branta Canadensis).
We have thousands of them in the Portland, OR area covering the parks and ponds. I've seen so many on a local soccer field you can hardly see the grass. They were introduced a hundred years ago when the Canada Goose was an Endangered Species. Now they are numerous because they don't migrate as there's plenty to eat in Oregon and Washington!