Ice.

With a stream literally at the garden border I never thought providing water for wildlife was necessary.   Then a friend made us a "bird bath".   I have never seen it used as a bath but it is frequently used as a drinker.  Then the trailcam showed a Hedgehog as a regular visitor.

To provide for him I put out a 25 cm (10") Plant" saucer".   This proved to be popular with both the birds and the hedgehog not to mention the squirrels.  So it became a permanent fixture.  When filling the feeders I thought "better lift the ice off the top of the drinker".   Wrong!   It was a solid block of ice with a leaf frozen in.  The best part of 5 cm (2") thick.