Ducks at the Park - Wild Ducks Grubbing Down Some Acorns

Ran into some wild ducks at a small park in Temecula, California. The female ducks have the brown feathers, with the stripe on the wing tips. The male ducks have mostly grey feathers with brown on their wings and chest, with a striking green oil slick head. The males also have tail feathers that curl at the end, while the females always have straight tail feathers.