Yobs

This. I'm sad to say, was so predictable because every year the local yobs think it funny to throw things on the ice, things that don't belong to them.

At least it isn't one of our bikes, he said nimbyishly.

P.S. I failed to rescue it because what you can't see is how broken the ice is between the bank and the foreground of the picture - it would have sunk without trace.