Pottery & Porcelain Marks – Birds: Marks of birds like hawks, eagles, swans, flamingos, and doves were used during the 19th and 20th centuries and are still in use today. The most commonly used bird is the American eagle. Shown either flying, sitting, or standing, the birds are marked on a variety of pottery and porcelain, for home, hotel, and kitchen. While some were printed on the pieces, many were impressed. Parts of birds, usually the wings, are also used as marks. The most famous of the American bird marks is used on Redwing Pottery.