In the article Bees & Trees in our last edition of the Castle Herald, we posted a picture of students floating a footprint trap in the castle moat. It was built by students from the Ecology and Land Stewardship group and was dubbed a ‘Mink Raft’. The idea was to check for the presence and then subsequently survey the population of invasive American Mink (Neogale vision) in the waterways across the Estate. This floating monitoring system encourages curious mink to climb on it to explore and as they do, they leave evidence of their presence in the form of footprints in a layer of sand and clay spread across the raft.
The students built the raft from scratch and displayed some highly competent woodworking skills. We should also say a massive “Thank you!” to the folks at Men's Shed for supplying the tools and wood. Their hard work paid off, because in March Simon Coppard announced that the trap had yielded what he believes to be mink footprints. As you can see from these photos, clear footprints can be seen and according to Simon they are definitely not water vole, otter, or rat, and they look closest to mink. An exciting discovery! The elusive mink, or minks are yet to be photographed, but in terms to come, Simon is keen to launch the raft again with another group of students, perhaps in a different location, to further the study and with luck, one day get a snap of our secretive visitor.
It is believed American Mink escaped from fur farms in the UK during the 1950s and 1960s and their descendants have been on the run ever since. Mink may look cute and cuddly, but they are very active predators that will feed on anything they can get their paws on, including nesting birds and endangered water voles. It is hoped that the survey raft’s footprint trap will also show the presence of otters and water voles across the Estate so we can start to compile a picture of their numbers.
The Castle Estate provides students with a living laboratory for studying the rich variety of microsystems it contains, and a wealth of biodiversity, which makes it perfectly suited for hands-on investigations such as these. We can’t wait to see what discoveries are made by our next cohort of students!