Invasive American minkEaster Sunday was a rare day out and about, all on official work duty – the government does allow non-essential work if it is something that cannot be done from home. And dealing with mink rafts is not something that can be done from home!

It was the last hot day of the recent glorious spell, and had long been planned as a day when I would take mink traps to two sites close to the Ouse Washes. One site where we caught three mink a couple of years ago was due another visit to see if any had returned. The second site was a new location where the residents had observed mink in the waterways and found out about my mink trapping network so called me over to try to deal with them.

But before all that, I had a trap alarm to deal with at the other end of the county, in the village of Duxford. The river Cam flows through a private garden here, where the gardener had spotted a mink back in February. We installed a mink raft and trap there as soon as possible, on the 6th Feb, but it had laid quiet ever since.

Having caught a mink on the Bourn Brook the day before, I had hopes that their behaviour had changed with the season and we might have caught another, but on checking it turned out to be a young rat that had gone into the trap. At least this showed us that the trap was working, and if the mink had stayed around we would have caught it by now. It was quite obvious when it was on the scene, but no-one had seen the mink or any evidence since the trap went in, so we assume it has moved on. Despite the lack of mink, it was nice to get out of the same location for a change and in the beautiful garden I saw my first speckled wood butterflies of the year.

After lunch I headed out to the Ouse Washes to set up the new traps. This area is one of the most important wildlife sites in the UK, with internationally important numbers of wintering and breeding birds, and at this time of year is important for migrating birds as well.

The Ouse Washes is a man-made flood water storage feature, designed to help drain the fens for farming. It is about 20 miles long by a mile wide, and can fill up with several metres depth of water in the winter, preventing the surrounding land from flooding. The resulting soft damp ground in spring is ideal for wading birds, ducks and other wetland birds. Site one was a small ‘borrow pit’ where some of the clay to build the flood banks was dug from. As such, it is a site that is not affected by flooding, so is a good spot for a mink raft.

The Ouse Washes were visible from the top of the floodbank nearby, and I could not resist taking a look at what was there. Over 1000 black-tailed godwits were the undoubted highlight. This is a rare breeding wader in the UK, with less than 50 pairs, but still common in Iceland. These birds were undoubtedly gathering for a feed before making the rest of their journey, timing it to when spring arrives in Iceland. They are fairly drab in winter, but most of these birds were in their spring finery, brick-red plumage. A superb sight and sound, as some of them tested out their breeding calls as well.

Grass Snake swimming Onwards to Sutton Gault, where the mink had been seen recently. This was a private garden on a drain connected to the tidal river. Again, a fairly steady water level made it a perfect site, and the owner was keen to deal with the mink as he has a collection of prize Koi carp in his garden. This was another great spot to look at the Ouse Washes wildlife, and the highlight here was probably the grass snake swimming along the main drainage channel. They are supreme aquatic hunters, particularly keen on amphibians, and this one was searching through the marginal vegetation in a definite hunting mode, no doubt hungry after four or five months hibernation!

Dr Vince Lea
Head of Wildlife Monitoring 

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