Up until 2002, GWCT advice on mink trapping was sound but conventional. It aimed to maximise success, but was based on accumulated experience not on any kind of systematic approach.
The GWCT Mink Raft was conceived in 2001 and first tested in 2002. It quickly became clear that the raft had immediate value in guiding mink trapping, and that ultimately it would help to generate sound advice on wider trapping strategy.
The mink raft actively solicits field signs by providing a structure that is highly likely to be visited by mink, as well as a substrate that reliably accumulates evidence of those visits between checks, which can be one to two weeks apart. The use of these rafts is the most effective means available to detect the presence of mink. Once a mink is detected, the raft(s) on which it left its tracks also becomes the best place to set a trap. The commonest result is that the mink is caught next day. Operating rules were developed empirically and tested through a succession of three mink removal projects of increasing difficulty. The last in this series was the River Monnow Project in Herefordshire, in which we demonstrated that we can turn back the clock by eliminating mink and re-introducing water voles, creating a tenable situation that can be maintained with modest resources.
Today mink rafts are used in many mink control projects around Britain and Europe, and even in South America. Although technologically very simple, they made a breakthrough in effective control of an unwanted invasive predator.
Because of financial constraints, these projects have all been development or demonstration projects rather than (expensive) experimental science. Their purpose is to show how successful mink control can be, given a small professional workforce, and also its limitations. Since 2003 we have offered workshops on mink control using the GWCT Mink Raft. Besides teaching the methods we have developed, a key purpose of such workshops is to guide expectations as to the cost and likely success of mink control. We take the opportunity to give advice on humane dispatch, and to discuss ethics.
At the same time, mink rafts became a useful tool in university-based research because for the first time it was possible to design experiments that compared ‘mink’ with ‘no mink’. Previously it had been possible only to compare ‘mink control’ with no mink control’, without knowing how effective