Even from afar, you can see how common goldeneyes (Bucephala clangula) earned their name.
Adult males have bright yellow eyes, females’ are pale yellow to white. But their eyes aren’t always that color.
When they hatch, common goldeneye ducklings have gray-brown eyes that turn purple-blue, then blue, then green-blue as they age. By five months of age their eyes are a clear pale green-yellow.(*)
Francis C. Franklin took this exceptional photo of a female wintering in northwestern England. Click here to see where Franklin found this beautiful duck.
(this Featured Picture at Wikimedia Commons is ©Francis C. Franklin, license CC-BY-SA-3.0. Click on the image to see the original.)
Common goldeneyes breed in the taiga of North America, Scandinavia and Russia. They’re found on both sides of the Atlantic.
(*) Eye color information quoted from All About Birds.
Yes they are found throughout the Northern Hemisphere, which is why they are called “common” (although they could also be called “northern” like pintails – since I can’t find any reference to them showing up in the southern hemisphere).
Rob, there’s a pintail in the tropics called a white-cheeked pintail — which is why ours are called northern: http://www.birdsoutsidemywindow.org/2015/02/01/a-saltwater-pintail/