A large heavily built duck that is uncommon to fairly common along rocky seacoasts; not found on lakes, unlike Flying Steamer-Duck. Both sexes are steely blue-gray overall, brighter than Flying Steamer-Duck, with a stouter and deeper-based bill. The bill of both male and female is bright orange in the southern parts of its range, but is orange with a greenish distal patch around Chiloé Island (likely a different species). The bill of juvenile birds is duller grayish to dull yellowish; attains adult color by winter.