After a long winter of hibernation, bats begin to emerge in early March and by April they will be out most nights, taking advantage of the warmer evenings to feed, writes our Conservation Officer, Will Scott-Mends. All bat species in the UK are insectivorous and mostly feed on flying invertebrates. In order to locate and catch their prey, as well as navigate in the dark, bats use a technique called echolocation. While flying, a bat will produce a series of ultrasonic clicks which will be reflected off any objects in their path. The bat will then listen for the reflection of these signals and use them to build up a picture of the world around it, allowing them to navigate in complete darkness.
We have 17 species of bat that permanently reside in the UK, meaning they make up almost a quarter of all our mammal species! Sadly many of these species have undergone significant decline in the last few decades with populations of some species declining by as much as 70%. This is predominantly due to habitat loss but many other factors such as artificial lighting, disease and diminished food supply play a role as well. Fortunately, thanks to the efforts of conservationists and bat groups nationwide, bat populations seem to be stabilising but there is always more work to be done.
International Dark Sky Week also falls in April from 16th to 22nd. It is a celebration of the night sky organised by the International Dark-Sky Association (IDA) during which people are encouraged to turn off outside lights and limit light usage at night to combat light pollution. It may not sound like much, but light pollution can have a major effect on nocturnal wildlife, particularly bats. Studies have shown that excess artificial light at night can have a serious impact on bat behaviour, preventing them from reaching feeding grounds, causing mis-timed emergence and even making them more vulnerable to predation.
Barnes Common Ltd will once again be running monthly batwalks around the Leg O’Mutton Reservoir which is an excellent site for bats. Last year’s walks were very popular with many interesting sightings, so please book early to avoid disappointment. Don’t worry if you miss out – there will be further walks every month until October and tickets will be available on Eventbrite from the beginning of each month.
These are our planned dates (TBC):
April 27th – 7:45pm
May 25th – 8:30pm
June 29th – 8:45pm
July 27th- 8:30pm
August 24th – 7:30pm
September 28th – 6:15pm
October 26th – 5:15pm