Dave Mount
>Daniel has it right, they're used for spearing through the ice, a small but signficant activity up here in the frozen country. Generally done from a darkhouse, small hut or outhouse-sized shack that covers a rectangular hole in the ice. Being dark inside, one can see pretty well down into the water. The decoys are jigged to attract fish, generally northern pike or muskies. The decoys are built so they travel in a circle when jigged up and down off a short stick. When a pike comes in to check it out, they are speared with a 3 or 5 tined, barbed spear. The spears are vaguely like pitchforks except they are barbed and the whole instrument is coplanar (all tines in the one plane with the shaft. They are also weighted to help them travel with authority down through the water, actually as much dropped onto the fish as thrown. This is not a "catch and release" sport.

Spearing decoys are generally homemade and are highly collectible, a kind of folk art similar to duck decoys.

There you go, more than you wanted to know. I gave you a linky below in case you still thirst for more. Page shows a view down an ice hole with a decoy and pike in view.

Best,

Dave