Canada Geese were always known to show remarkable size variation. DNA studies indicate small Canada Geese are quite different from larger ones. Recently ornithologists declared that the smaller ones are a separate species named Cackling Geese. One problem is that larger Cackling Geese are about the same size as smaller Canadas.
Birders and ornithologists have always been confused by goose races. An recent study proposed splitting Canada and Cackling geese into six species and 200 subspecies. This study, however, remains controversial. In any event, this photograph is definitely of a Cackling Goose. It is about the same size as nearby Mallards. I took the image at the Superior Drive Pond in Northfield on 4 March 2017.