Results from The James Williams 2 day otter survey in Somerset.
With the increasing interest in otters and with it, those writing pieces about otters, the Somerset Otter Group survey data can be found repeated in articles elsewhere, either to try to answer the clamour to know ‘how many?’, or, to add credence to the writers knowledge. Beware such articles simplifying, interpreting and quoting this data.
Below is a good summary of the data for this year from the Somerset Otter Group, it is a part of the picture of otters the group has built up over many years.
The survey and the methods of scoring have been honed over many years by James Williams. This has produced comparable data through the years to monitor the Otter population in Somerset and to hopefully flag up problems as early as possible. One of the sets of data is adjudicated ranges, a ‘guestimate’ abstracted from the fresh otter signs recorded across Somerset on a single night. This is the number most often taken, misinterpreted and misunderstood. This year’s low score will need a lot of work to interpret further.
Somerset Otter Group 2016 Survey
Adjudication by Jo Pearse.
This year’s 2 day spring survey saw 119 surveyors cover the main water bodies across Somerset. As in previous years 7 surveyors from Devon ensured Exmoor National Park was covered.
This year extra coverage was possible on the Brue catchment by the help of volunteers from the Somerset Wildlife Trust Reserves, the RSPB at Ham Wall and on the Parrett with support from the RSPB at Greylake, West Sedgemoor Reserves and the Wildfowl and Wetland Trust on the Steart Peninsular.
Some sites were affected by the Friday rain and one coastal site was flooded by the last of the high spring tides. However, elsewhere water levels were normal, to widespread relief, allowing the spriant collection for Cardiff University’s genetic study on the Tone and Brue catchment.
Surveyors from the Tone and Brue catchment collected fresh spraint from both days in the hours following dawn.
Paul Hillary was lucky enough to have a sighting, but unfortunately the otter swam off before depositing a spraint.
Patricia Stainton offered her home on the upper Brue and Bob Bailey opened his house and fridge as a collection point for the rest of the Brue catchment spraints.
The final collection point for all spraints was at Stoford Manor. Elizabeth Williams’ provided a room for Saranne Cessford to set up an office and meticulously record all the spraint collected. She arrived soon after 7am, after her own survey, and by 5pm the samples were handed over to the genetic student, Nia Thomas, who left for Cardiff University with all the spraints. It is a three year study, so it will be some time before the results become available.
We surveyed 139 patches, a total of 532 sites of which 304 were positive. 25 blanks, the highest ever, the average being 12 over the last 7 years . 57% of sites had some signs and of all the sites, 15% had fresh work on the second day. This is the lowest percentage of positive sites for fifteen years.
An initial examination of results for this year reveals 56 otter ranges were located. Although lower than usual there is reassurance by the breeding information that came from the event. Across the county, either noted during the survey or from recent camera footage, 7 separate records of cubs were sent in.
The ranges can be broken down across the catchments as: North Somerset Streams 6, Somerset Exe 5, Tone 11, South Coast 3, Parrett 13, Brue 11, North Axe 2 and Frome 5.
The Somerset Otter Group as usual was able to provide an excellent record of other species. Surveyors found signs or sightings at the following number of sites: bittern – 2, cormorant – 1, crane – 1, dippers – 18, little egrets – 3, grey herons – 2, grey wagtails – 5, hen harrier – 1, hobby – 1, kingfisher – 13, mandarin ducks – 2, mink – 3, moorhen – 1, red fox – 1, redstart – 1, roe deer – 1, sand martin – 1 and water voles – 3.
The date for next year’s event is 22nd and 23rd April 2017
|Somerset Catchments||Patches||Sites||Positives||Hits||Near Miss||Blanks||Otters|
|2016. 2 DAY EVENT RESULTS|
|% sites Pos||57%||74%||66%||55%||81%||61%||59%||18%||8%||65%||0%|
|Sites with hits||71||3||4||12||3||21||15||3||0||10||0|
|% sites with hits||13%||6%||7%||10%||27%||17%||17%||7%||0%||34%||0%|
|% positives with hits||23%||8%||10%||18%||33%||28%||29%||37%||0%||52%||0%|