Chicks and ducks and geese better scurry

I know that cows lying down means that it's going to rain, but what does it mean when you see two ducks sitting in the middle of a car park? Why would they feel the need to keep their bottoms dry when they spend so much time getting wet? Is it just an indication that it's likely to be cool and slightly overcast, as this afternoon proved to be? If so, that's some mighty fine weather forecasting -- far better than the fools on TV.