Henderson Bird Viewing Preserve, Henderson, Clark Co., Nevada, USA.
Seen with many other water fowl. Head band appeared bluish-purple from this angle, but I think that may just be a quirk of the lighting.
The Eurasian Teal or Common Teal (Anas crecca) is a common and widespread duck which breeds in temperate Eurasia and migrates south in winter. The Eurasian Teal is often called simply the Teal due to being the only one of these small dabbling ducks in much of its range. The bird gives its name to the blue-green colour teal.