NWT Otter Survey

Otters © Elliot Neep

During 2016, Northumberland Wildlife Trust launched a county-wide survey for otter populations with the support of dedicated volunteers.

This was the first otter survey carried out in 13 years, thanks to a substantial legacy from Berwick resident and member for over 15 years, Vera Wainwright with a specific request that the gift was applied to an otter project in Northumberland.

Otters are generally difficult to see and surveying with normal survey techniques is quite challenging. Therefore, NWT signed up a team of volunteer surveyors for a number of sites across the county to look for signs and collect spraint (otter droppings) from these locations.

The Trust has led the way in otter conservation projects across the country and carried out an almost continuous annual countywide survey for signs of the species between 1990 and 2003, using large numbers of dedicated volunteers. This provided a virtually complete set of presence and absence data for the county and has been used as the yardstick for otter conservation efforts in the region ever since. It was, in the end, the success of these conservation efforts, with over 80% of sites showing signs of otter presence, and a lack of funding that brought these county-wide otter surveys to a close in 2003.

Volunteer surveyors were allocated survey sites along stretches of the county’s rivers and allowed to visit their sites at their own will, between certain set dates (allowing a settled period of weather for the optimum recovery of otter signs). Evidence was collected and recorded and, where necessary, returned to the project officer for verification; any gaps in the survey map were completed by the project officer to attain full coverage of remote sites.

The results from the surveys are very exciting and above what were expected, given the precariousness the region’s weather. Consistent proof of otter presence was recorded and, across the county, results indicated a slight increase in presence since the last full county survey in 2003. Specifically 164 sites (91%) from the 180 sites surveyed showed signs of otter presence, an increase of 3%. It is a good indicator of a strong population presence.

The River Tyne had only three negative sites from 80 survey sites, making the catchment 97.6% positive for the presence of otter - an exceptional result. Mink presence was also recorded throughout the survey and resulted in a 24% level of site presence, an increase of 10% on the previous survey results, where only 14% of sites surveyed mink evidence present.

The team made a conscious effort during this survey to try and determine some population dynamics through sampling DNA from spraints collected on the River Tyne. Unfortunately DNA science is not that definitive in certain collection methods, and especially, in relation to otter spraints - it is still not an exact science and although attempts were made to identify markers, no conclusions could be drawn from the samples collected on this occasion. The reason for this was the extreme wet weather over the winter of 2015/16 and the fact that spraints have to be collected very, very ‘fresh’, all conspired to reduce the effectiveness of the effort.

From these results there can be little doubt as to the long term benefits of otter conservation; as part of the rehabilitation of the regions watercourses and improving water quality, this can be seen by the healthy presence of the animal recorded during this survey of Northumberland.

The full report can found here.

If you would like more information about the project, contact Kevin O'Hara on (0191) 284 6884 or email mail@northwt.org.uk.

If you do spot otters in the Trust's catchment area please do let us know.