Pips and Daubs
Bats are by far the most numerous canal mammals. Several species, including Daubenton’s and pipistrelle, roost in canal structures along the River Wey and forage for insects over the water, the towpath and along the adjoining corridor.
The pipistrelle is the most common British species of bat. It is also the smallest. It's flight is high and appears jerky as it dodges to catch insects in flight. A single pipistrelle can consume up to 3,000 insects in one night.
This bat is a medium-sized species that is often seen flying steadily within a few centimetres of the water’s surface. These bats take insects from close to the water’s surface hence their common name, the 'water bat'. They make summer roosts in trees and bridges along the towpath.
How bats catch and find their food
At night when the bats are foraging, their ears are more important than their eyes. As they fly they make shouting sounds. The returning echoes give information about anything ahead of them, including the size and shape of insects and which way they are going.
This process is called echolocation. Most of these sounds are too high-pitched for humans to hear, but they can be heard with a bat detector.
What does a bat do at night?
What a bat does at night is still not fully understood. Lots of our well-known species leave the day roost at dusk and return at dawn. They come back fatter and tired, having consumed possibly thousands of insects, and flown as far as twenty kilometres during the night.
Weather conditions obviously affect a bat’s dinner possibilities. If it's cold, wet or very windy, insects are not likely to venture out. If there are no insects, there is little point in a bat going out, as it will be using energy that it will not be able to replace.
If you walk along the River Wey towpath in the early mornings, you are likely to see lots of damselfly wings on the ground. This is one indication of what bats have been doing at night...
To find out more, visit the Surrey Bat Group's website