Wednesday, 24 February 2010

In search of otters

The possibility of otters along the Ock has intrigued me for a while - apparently mink used to be common, but something must explain why it is now a stronghold of water voles and young moorhens (another favourite of mink) and otters have been reported along the Thames at Iffley meadows and at Radley Lakes in north Abingdon. Also, BBOWT have reported that an otter spraint has been found at one of their reserves through which Sandford Brook - a tributary of the Ock flows. 
So I've been checking out various possible places where otters may leave spraints, which they use for marking territory and beneath the bridge, where the Ock flows under the A34 I found this:

It is defiantly, not dog (I've seen and stood in enough of that to know what that is), but it could be an otter spraint or mink scat.  There are two tests to tell them apart:

1. Smell: An otter spraint can smell of jasmine or lavender , a mink scats just smells awful.
2. Contents: An otter spraint will contain fish bones and scales, whilst a mink scat contains mammal fur.

I didn't recall in horror when I smelt it, so it probably wasn't mink, so I took it home and a dissected it on the kitchen table - the contents of it are obviously fish:

Whilst dissecting, it produced an even stronger grassy smell, definitely otter.

The territory of an otter can vary - depending upon the size of the population and the abundance of food - from 1 to 20 miles, so this could be the same otter that was reported by BBOWT - if it is, then it may risk crossing the Marcham road, a busy road to the west of Abingdon.

The return of otters to English water ways has to be one of the conservation success stories of recent years. It was almost extinct in central England with only a significant population in the west  and fragmented populations elsewhere.  It was not until the banning of certain pesticides along with the 1979 otter hunting ban has the population recovered and this record of a spraint can be added to the increasing numbers recorded elsewhere in Oxfordshire.


  1. You're a braver man than I!
    Seriously though, if your investigations are correct that would be fantastic news.

  2. I'm convinced it's otter, so as you say fantastic news as it shows not only otters are making a comeback, but the river itself is clean enough to support them.
    Dissecting was the easy bit, just dissolve it water and pick out bits with tweezers. The brave bit was telling my wife of the mess on the carpet where I dropped some....

  3. Well done Richard, for spotting and dissecting the spraints.
    A dead otter (road kill) was found last year at Clifton Hampden, about 5 miles away.

  4. Hi David,
    Thanks for your comment, even if it contains somewhat sad news. But it shows that we seem to have a healthy population of otters in the locality.
    It also appears otters now have the same threat as badgers - the motor car.

  5. Definitely otter, just from looking. Mink scat is darker and twistier, like ferret poo.

  6. Very useful and so peaceful blog for us. Such a good work and so good write up.