Holes in pond ice

Two good friends of mine were telling me about their amphibian casualties (one found 6 dead froggies in his pond!) following the December frosts so I'm now back to making holes in the pond ice to ensure the pond life in there doesn't run out of oxygen.

I find my enamel mug good for this job as it gets quite hot. I'm not sure how useful this will be but one can only try...