Common voles are revealed by their runways above the earth which lead from the burrow entrances and connect these. The whole surface is often covered in mouse holes. 1.5 mm wide, and by water voles approx. The burrow should then be closed again so that it does not let in the light. The water vole activates the trap by pulling at the bait.
Trapping allows direct controlling of success.
A practised catcher is able to work more effectively with this method than for example by fumigating, since the time needed for live-trapping is less as a whole. Carbon dioxide can be obtained for example in gas bottles from drink suppliers. By way of a short plastic pipe, the gas is directed into the burrow system for approx. 5 minutes at 0.5 to 1 bar. At 0.5 bar, approx.