Twenty years ago, the chances of seeing an Otter in the Cotswold Water Park area were slim at best. Nationally, they had suffered a massive decline, particularly during the 1950’s and 60’s, and despite my keen interest in wildlife I didn’t see a wild one, anywhere, until about 10 years ago. That situation has now changed, Otters have made a comeback and I expect to see them two or three times a year in the CWP.
Encountering them is still far from straightforward; they are largely nocturnal and also roam over very large territories (they have been recorded making use of up to 40 kilometres of river!) However, on grey, damp days (in particular) they are increasingly seen during daylight hours. Early morning is probably best, but any time of day is possible. They inhabit both the gravel pits and our network of small rivers; quieter areas are likely to be best, as they tend to steer clear of humans. If you do see one, stand still – it might not detect you, especially if the wind isn’t blowing your scent towards it. 
My most recent encounter was on a small river; I was lucky enough to encounter a mother with 3 nearly full grown cubs and, by keeping still, I was able to watch them feeding for about 10 minutes. They were catching Signal Crayfish – an invasive American species which have almost wiped out our native White-clawed Crayfish. So they were doing their bit for conservation! Through the warmer months, in particular, Otter spraint (nice term for poo) is usually ‘Crayfish pink’, demonstrating their food preference. The spraint is usually found on favoured flat, bankside areas, where they climb out. If the bankside mud is soft, Otter footprints can be seen too. Fish also make up much of their diet, with the large territories ensuring that they don’t overfish an area.
When they aren’t feeding, they usually retreat to a holt – which will involve a bankside hole, often under tree roots. You won’t see them there; but with luck and good observational skills your chances of seeing them in the CWP are far better than they used to be.
Kim Milsom, Biodiversity Field Officer, Cotswold Lakes Trust