The cackling goose (Branta hutchinsii) and the lesser Canada goose (Branta canadensis parvipes) are two subspecies of geese that are often confused with one another. Both species are similar in appearance, but there are a few key differences that can help you to tell them apart.
One of the most noticeable differences between the two subspecies is their size. Cackling geese are typically smaller than lesser Canada geese, with an average weight of 2-3 pounds compared to 4-6 pounds for lesser Canada geese. Cackling geese also have a shorter wingspan than lesser Canada geese, with an average wingspan of 36-42 inches compared to 42-48 inches for lesser Canada geese.