Note the powder blue wing coverts visible in the open wing. This striking duck breeds in freshwater ponds and wetlands in Western North America primarily south of the Prairie Pothole region. Its North American population has been estimated at fewer than 300,000 making it one of our least common dabbling ducks. In the Bay Area, these birds are primarily migrants, especially in the Spring, but they also winter locally. Formerly placed in the genus "Anas." Here is a short video clip showing two males interacting with a third:
https://youtu.be/EkGa8I3bEHU
