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Wood and hedgerow mammals

In the first of a three-part series on Dorset’s mammals, Colin Varndell looks at the smallest of our county’s furry creatures

My first memorable encounter with small hedgerow animals was on farmland near Loders in west Dorset. I was standing under a mature, overgrown hedge listening to the sounds of the night as I waited for a litter of fox cubs to appear further along the hedgebank at dusk.

Tawny owls prey on wood mice and other small rodents in woods and copses

Tawny owls prey on wood mice and other small rodents in woods and copses

The evening stillness was interrupted by tawny owls calling and the occasional wingbeats of bats as they hunted overhead along the hedgerow.

Wood mice coming to peanut butter which has been spread on this stick to attract them

Wood mice coming to peanut butter which has been spread on this stick to attract them

A piercing squeak suddenly broke the silence, followed by frenetic rustling sounds as some small creature scurried in the leaf litter. Two wood mice came scuttling along the bank, one chasing the other and both squeaking angrily. They were too engrossed in their dispute to notice me.

A field vole, feeding amongst golden saxifrage in spring

A field vole, feeding amongst golden saxifrage in spring

In the moonlight I could see that their tails were held erect in the aggressive posture; I was witnessing a territorial quarrel between rival male wood mice. The squabble did not last for long and the mice dispersed in opposite directions. The intruder having no doubt been successfully expelled, which is most often the case in such disputes.

 In summer, dormice are active up in the trees and hedges, rarely coming to the ground

In summer, dormice are active up in the trees and hedges, rarely coming to the ground

This chance meeting with wild mice triggered a curiosity to get to know more about the small mammals inhabiting the Dorset countryside.

This small mammal's ears give it away as a bank vole

This small mammal’s ears give it away as a bank vole

But observing such creatures in the wild is difficult, as many of them are only active after dark and even when they are on the move they are quick and secretive.

A common shrew, notice its fine snout, ideal for seeking out invertebrate food

A common shrew, notice its fine snout, ideal for seeking out invertebrate food

The sheer diminutive size of small mammals, makes them ideal menu options for a range of predators, including hawks, falcons, owls, foxes, various mustelids (weasels, stoats etc) and even reptiles. To counteract this, they have to be secretive in order to survive. At the same time, considering their short life spans, they also have to be prolific breeders.

 A pair of harvest mice greet each other in a hawthorn bush

A pair of harvest mice greet each other in a hawthorn bush

For example, a female wood mouse is capable of producing up to six litters a year, between spring and autumn, each containing between four to eight babies.

The adder is a serious predator of small mammals in Dorset

The adder is a serious predator of small mammals in Dorset

This phenomenal breeding potential is seldom achieved in the wild though, due to the high level of predation.

The brown rat has been on the increase in Dorset in recent years

The brown rat has been on the increase in Dorset in recent years

In spite of heavy predation, several small mammal species occur in huge numbers across the county, supporting the populations of the larger, more familiar, predators.

An adult hedgehog rummaging in leaf litter in autumn

An adult hedgehog rummaging in leaf litter in autumn

Monitoring the secret lives of small mammals is not easy, but by studying signs of their tracks, trails, nests, holes, food remains and droppings it is possible to build up data to help us to understand more about them. ◗

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