Where are the ducks and moorhens?

The pond has had a thin layer of ice for 3 or 4 days.  The first day the 5 ducks just stood on it.  No sign of the moorhens.

So I wonder where these birds have gone?

Update on the rat situation..the 4 sources of poison have been eaten...There are no scratching sounds from under our decking.  We have placed some more poison inside the traps, just to make sure.
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