On the common at the top of Barnet there's a ratpond. It is disguised as a duckpond to lure lots of little children with their breadcrusts- when the ducks are stuffed, the rats slither out of the drainage pipe and gobble up the leftovers.
Horrible duck joke: Q. How do you turn a duck into a soul singer? A. Put it in the microwave until its Bill Withers.