Published: 03 October 2013

Researcher’s film proves otters are back in Surrey after 50 years

A PhD researcher in computing has filmed an otter family on the River Wey using hidden cameras, providing photographic evidence of otters in the area for the first time in 50 years.

In the 1970s otters were close to extinction, but they are slowly recovering in Britain given the ban on pesticides and the improvement in water quality and related fish stocks.

Aaron Mason has filmed the otters during his research project, called ‘Wildsense’, working closely with the Zoological Society of London (ZSL) and Surrey Wildlife Trust.

Jim Jones of the Surrey Wildlife Trust said, “The cameras have captured members of an otter family, one adult and two juveniles about 14 times in the summer. This is the first time we have had photographic evidence of otters and the first evidence for breeding otters in Surrey for 50 years so it’s very exciting.”

Aaron said: “It took several weeks to finally get proof from the cameras. We went for weeks with no activity but then we repositioned our cameras.

“I was getting instant automatic email updates from the internet-connected camera but all the photos were triggered by other activity such as wind movement or falling leaves so I was getting quite concerned.

“Then we moved the camera position and about a week later I woke up one morning to check the emails as usual and was delighted to get the images proving otters were back at last.

“It’s about time they came back where they truly belong.”

Surrey Wildlife Trust has been working hard to encourage otters back in to Surrey. They have been liaising with the Environment Agency (EA) on the Otters and Rivers Project since 1997, improving conditions for otters by providing animals with places to rest up and build homes or ‘holts’ and encouraging them to breed.

Professor Paul Krause, of the University’s Department of Computing, who is supervising Aaron’s project, explained: “Aaron's automatic cameras are able to augment the evidence from otter “spraints” (droppings) with good quality photographs and videos.

“From analysis of the time and location of the photographs, the Surrey Wildlife Trust are now able to collate information about the movements of the otters without intruding on the behaviour of the otters.”

He added that there are plans to widen the scope of the research which is already being applied to monitoring tiger movements in India as part of the ‘Tiger Nation’ project.

Aaron calls it a ‘citizen science project,’ as people are contributing to science with their findings.

Aaron said: “It’s really exciting to be involved with Surrey Wildlife Trust for such an important project. I am very pleased that Wildsense is proving effective and making an impact. These are just the early stages of the project which has potential for tracking animals on a much larger scale.”

Surrey Wildlife Trust has created an Otter Spotter’s Guide as members of the public often mistake minks for otters. The guide states: otters are milk chocolate brown with a long, tapering sleek tail, minks are plain chocolate brown with a round, fluffy tail. Otter droppings have a hay like smell, mink droppings give off a rancid fish oil scent.

The Trust also has a new initiative called RiverSearch through which volunteers can learn to survey for otters and water voles and help the volunteer recovery effort for these species. If you’d like to get involved contact

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