Why do we need to control mink?

American mink (Neovison vison) are very effective introduced predators and consequently many prey species have not evolved effective defence strategies. They have a significant impact on native wildlife including a wide range of birds, rabbits, fish, and game, as well as water voles.

Mink were first introduced into Britain for fur farming in the 1920s, establishing themselves in the wild throughout the UK as a result of escapes and deliberate releases. They were first recorded breeding in the wild in 1956 and are now present in almost every county in Britain. It is now an offence to release or allow the escape of mink into the wild.

They are mostly nocturnal or active at dusk, but may be seen at any time of the day. Their presence can often go undetected and the first indication that they are about may be that stretches of rivers or lakes lose their moorhens, coots and water voles.

Mink Rafts

Mink rafts were developed by the Game Conservancy as a tool to monitor for the presence of mink, as they leave footprints on a clay pad when they visit.  The raft then forms an excellent base on which to set a cage trap.  Mink rafts are the main detection and control method used by the project although traps may also be set on the bank.

Raft placement

Each raft needs to be positioned with care giving consideration to flood defence, so as to avoid causing a blockage in, or otherwise impeding, a watercourse. The exact position of each raft is a compromise between flood defence considerations, health & safety for checking, convenience of access, public visibility, and likely spots for detecting mink.

Rafts are placed away from in-stream structures, except for groynes where they may be placed downstream of such a structure. A raft may be placed close to or under a bridge only if there is sufficient space below the underside of the bridge under flood conditions for the raft to float freely. Rafts must not be placed close to and upstream of flood defence structures or weirs. Rafts must not be positioned where they could themselves cause an obstruction.

Raft Inspection

In monitoring mode, the clay cartridge is installed without a trap and the raft is checked every 1 to 3 weeks. To assist access to the clay cartridge and to reduce the risk to the checker, the raft may be pulled to the shore and partially onto the bank. The clay cartridge is removed and inspected for footprints or other field signs. Once these have been recorded, the clay surface is smoothed over and the clay cartridge replaced in its hole under the tunnel. An effective method of smoothing is to remove any debris then dribble a little water over the surface and gently run the fingers back and forth over the clay until indentations have disappeared. To prolong the life of the clay, every few months the clay can be turned over by digging a finger into one corner of the cartridge, carefully easing and lifting the clay out in one piece, then flipping it over and relaying it place before smoothing over.

For some reason otters can vandalize the clay cartridge, we are not sure why they do this but it can become annoying after a