Conservation UK - The Polecat Report

3rd February, 2009

A three year study on the whereabouts of wild polecats in Britain has concluded with the launch of the Polecat survey of Britain report. The survey brings good news that the polecat (Mustela putorius), a nationally important species(1) that was trapped to near-extinction by 1915, is continuing its twentieth century spread from its historical stronghold in Wales into ‘middle England’, moving east and south across the country.

Author Dr. Johnny Birks will be at the conference to provide the first copies of the report. He said “As a result of this survey we can now estimate that the population of polecats in Britain totals nearly 47,000 animals. That’s an increase of 22% since our last survey in 1997 and an annual increase of around 2.4% Most of this increase has been within eastern and Southern England.”

The survey was based on the public coming forward with information and visual evidence of sightings of polecats (alive or dead) which were then verified by experts. This produced a total of 1,273 records over a period of 36 months and was concentrated within 530 ten kilometre square areas. The key to the survey was distinguishing between true wild polecats and polecat-ferrets, animals originating from the domestic ferret or escapees from captivity. Comparing the two forms, true polecats were sighted more than three times as often as polecat-ferrets.

Regionally there were strong trends identified by the survey:
Wales and the West Midlands had the purest populations, where more than 95% of the sightings were true polecats
Beyond this western ‘purest’ polecat zone lie zones in which polecat-ferrets are encountered with increasing frequency towards the eastern fringes of the polecat’s range.
Derbyshire, Buckinghamshire, Berkshire, Wiltshire, Dorset, and Hampshire were the counties showing greatest expansion of the polecat population since the previous survey of 1993-1997.

An interesting observation from the statistics showed that a significantly greater proportion of true polecats than polecat-ferrets were recorded as road traffic casualties in Autumn when juveniles are dispersing into new territories. Dr Birks hypothesises that this may be an indication that polecat-ferrets are less successful at breeding and surviving in the wild.

The report concludes with ten calls to action for the future conservation of the polecat:
maintaining and enhancing habitat quality
reducing the secondary effects of rat poisons
reducing mortality in spring traps
reducing road traffic casualties
reducing interbreeding with feral ferrets
improving confidence and rigour in polecat recording
promoting tolerance and understanding of the polecat
distribution-mapping at ten year intervals
confirming the status of populations outside the main expansion range
monitoring abundance

Points two, five and ten are already being pursued by The Vincent Wildlife Trust. The Trust is commissioning further research into genetic interbreeding with feral ferrets and funding research into the secondary effects of rat poison contamination. In addition the Vincent Wildlife Trust leads an annual polecat and mink abundance monitoring system using local volunteers to record road traffic casualties during the months of September and October.