I've wanted to add this duck to my life list for some time, ever since I saw the common goldeneye with its circular cheek patch. At first glance there doesn't seem to be much else different between these two types of ducks, but this sighting gave me an unmatched opportunity to see both species in close proximity. They are actually quite different in their coloration, with the Barrow's goldeneye being a darker bird with more prominent black. The head shapes of the two species are also bit different, though that's hard to tell because they change postures frequently.
In behavior, they do act similar - both goldeneyes were very skittish as I watched, even though the path I was on is set a bit back from the riverbank, and the river itself is wide and open in that area, providing good visibility. In contrast, the mallards, northern shovelers, and Canada geese that were also in the floating flock didn't mind my presence at all.
What a treat to add this bird to my life list; the first of many I hope to see in 2011. May your birding be as productive all year long!