True. Some hang around though if it’s a mild winter and there’s open bodies of water.
According to a U.S. Fish and Wildlife Service 2013 report [PDF], there are more than 5 million breeding Canada Geese in North America. But within that vast number are two distinct populations: migratory birds that breed in northern North America and winter in central and southern North America; and resident birds that live in and around towns year-round.