Gustavsson CG. A white feathered area on the forehead is more common in hybrids of Greylag Goose Anser anser and Greater Canada Goose Branta canadensis than in the parent species. Ornis Svec [Internet]. 2011 Jan. 1 [cited 2024 Nov. 22];21(1):37–44. Available from: https://journals.lub.lu.se/os/article/view/22617