(Australia)A coded warning used by men to alert each other that female guests ("ducks") are present ("on the pond"), so that for politeness they should moderate their language.
1982, Patsy Adam-Smith, The Shearers, Thomas Nelson Australia, ISBN 0-17-005884-0, page 245.
Usually the wool presser calls first, because most visitors to a shed come through the wool room. ‘Ducks on the Pond!’ he calls, and the warning is taken up again down along the shearing board.