I had a hard time identifying this bird. The two that I saw had sort of brownish breast plates, not black like the bird that I think it is. It had a pure white stomach like snow that went all the way back to the tail, with a white spot on the tip of its tail feathers as well. Other than that, I think it is a Black Turnstone of the Sandpiper family even though it's missing its distinctive white spot between the eye and bill. I found them on the rocks at State Beach in Ventura, California.