This striking medium-sized duck is widespread across much of North America, Europe, and Asia, where it inhabits various wetland environments. It breeds in lakes, ponds, and marshes, and during the winter, it can be found on inland lakes and rivers or in coastal bays and nearshore waters. Adult males feature a black head with a circular white patch at the base of the bill and a mostly white body with limited black. Females and first-year males have a gray body and chocolate brown head, with bright yellow eyes that stand out on all but first-year females. It is very similar to Barrow’s Goldeneye. The easiest way to distinguish males is that the Common Goldeneye has less black on the back, lacks a dark spur on the side, and has a circular rather than crescent-shaped white patch on the face. Differentiating females is more challenging; the Common Goldeneye usually has a dark bill with a small yellow patch near the tip but can occasionally have an entirely dull yellowish bill similar to Barrow’s. Head and bill shape are also important identifiers: the Common Goldeneye has a more evenly rounded head with a peak in the center of the crown and a longer, straighter-edged bill.