Herts and Middlesex Wildlife Trust have just completed a water vole survey of Hertfordshire waterways. They looked in the Colne and Ver but sadly found no voles. Their interesting and beautifully produced booklet, Water Vole Habitat Management, explains exactly why.
Too steep, too shady
Water voles eat plants - a vole’s diet can consist of 200 different, low growing plant species. They thrive where the river banks are gently sloping and not shaded by trees and there are many plant varieties. The last water voles seen locally were in the river bank opposite the Green Dragon. The water level should also be fairly stable. Water voles can drown if the water level rises quickly as they nest in burrows in the banks. Reinforced banks as are found in places on the Colne prevent water voles from burrowing. Their burrows have entrances above and below water so that they can evade land and water predators.
Mink and rats
Mink kill water voles and have been seen, though not recently, near the river in London Colney. Mink look a bit like polecat ferrets and have dense glossy deep brown to black coats. If you see one, tell the Wildlife Trust, they are based at Grebe House on the edge of Verulamium Park. Rats also kill young water voles and
probably carry diseases that can affect voles too. For whatever reasons, an increase in rats in an area brings with it a decrease in water voles.
Have you seen one?
Water voles are also often mistaken for rats. Both are found by rivers, they are a similar size and colour but look carefully. Rats have long scaly tails, a pointed muzzle and large ears. Water voles have rounded, blunt faces, their ears are small and hidden in their fur and their tails are shorter and hairy. However, you can be sure that if you see a brief glimpse of a brown furry body followed by a loud plop as it dives into the water, that was a water vole. Rats are more likely to waddle off, fairly unconcerned unless you have a dog with you and won’t take to the water unless cornered.