Black bellied whistling ducks! Weirdly enough, I've had them appear in my yard several times. About two dozen would hang out with my domestic ducks and geese around the kiddie pools for a few hours. Then they'd fly off. This happened three or four times months apart. All my pictures are blurry.

Not as nice as what you find, but these are the first ones I found where I planted spawn a year ago. I'm chuffed!