Photo: Mink with water vole prey, North Lincolnshire; credit Graham Catley / WRT
It's a year since we last reported on the mink situation, and we're happy to say there's been huge progress both on the Ivel and in the East of England generally.
As a reminder, the invasive non-native American Mink Neovison vison is a vicious predator which has caused the loss of a wide range of river wildlife in Great Britain, particularly Water Voles which were once a common sight on the Ivel, but no more.
For a long time, mink eradication was thought to be impossible, but a project started in Norfolk just five years ago using some new tech has changed everything to the extent that eradication of mink from the whole of Great Britain has become a distinct possibility in the next ten years.
The Waterlife Recovery Trust (WRT) is leading this incredibly successful effort, and we strongly recommend you subscribe to their newsletters; The latest one, No. 7, has just been published, and all of them are a fascinating read.
The Environment Act 2021 includes a legally binding target on species abundance for 2030, Water Voles are one of the target species, and Natural England (NE) is the government agency tasked with implementing it in England.
It's the same old story all over again, the fundamental problem with our river is over-abstraction, but instead of trying to do something about the unpalatable truth, all anyone wants to do is 'habitat renewal' which generally involves multiple desktop studies going on for years and years, and eventually, diggers, neither of which will get perennial water back in our river. And so it is with NE who favour water vole habitat renewal and reintroduction which anyone with any knowledge of mink behaviour will say are just expensive mink feeding schemes unless the mink are removed first.
Faced with incontrovertible evidence that the WRT approach really works, NE did finally grant some support in the middle of 2023. This has enabled WRT to purchase a bunch of new traps and hire several area coordinators on18 month contracts to expand the active area of Norfolk, Suffolk and Cambridgeshire, out to Essex, Hertfordshire, Bedfordshire, Northamptonshire and south Lincolnshire.
RevIvel is the 'first responder' for eight smart traps on the Ivel above Henlow and Cat Ditch. Two of them are coordinated by the Herts & Middlesex Wildlife Trust, the rest, in Bedfordshire, directly by WRT. In the last eleven months we have sent off 23 mink for scientific analysis, and there's been equivalent success by our colleagues in the rest of the Ivel catchment. Judging by the Norfolk experience, where no mink have been caught in any of the 500 traps there for more than a year, there's a good chance there will be no mink left on the Upper Ivel by 2026, or at least so few mink they are not a viable breeding population.
Meanwhile, NE have still not committed to a national campaign. Outside the core area WRT have been supporting miscellaneous wildlife trusts and groups who have found the funds to acquire a few smart traps of their own, but it is all a bit fragmented, which isn't ideal; NE really must get their act together if they are to achieve the task given them by Parliament.
There's general agreement that water vole numbers had diminished by at least 95% across the country, and that they had been completely extinguished in some areas. Given this situation, two hugely important, linked questions follow: If mink are removed, will water voles recover and, if so, will they return naturally, or will they need artificial help in the form of human-controlled re-introduction?
To the extent that water voles have become so common in some areas cleared of mink that keeping them out of the mink traps has become a problem, the first question is answered (captured water voles are of course released unharmed). As for the second question, once the mink have gone, WRT have found water vole populations sometimes appear to materialise out of thin air, even in places where none have been recorded in years or decades, but it's still too early to say whether this will happen everywhere.
The logical conclusion to this is that first you need to get rid of the mink, then watch what happens for a while. If, after a few years there's no sign of a reappearing water vole population in a particular area then reintroduction should be considered. There is therefore some scope for the beloved desktop studies, but one thing is quite certain, once the mink are removed, water voles are perfectly capable of looking after themselves and need no help from do-gooders with diggers.
