Bufflehead. It's not a bird I would expect to see in a shallow, narrow drainage ditch in the middle of suburbia. More typically they are seen on large ponds, lakes, harbours and bays. I startled her as I rode my bike along the adjacent paved path. She flew above the ditch in the same direction I was going. She thought I was chasing her, and it sort of, inevitably, became a race. Yes, I can pedal as fast as a small, panicked duck can fly (into a brisk headwind, I add).