by Meg Noble from Sheepdrove Farm
On the 30th August, hundreds of people will be gathering across 30 different countries at dusk for International Bat Night. It takes place on the last full weekend of August, and has been celebrated on this weekend since 1997.
We have many experts arriving at Sheepdrove for International Bat Night, the hope is that we can catch a glimpse of some rare and more elusive species, but we already know that we have healthy populations of some more common species.
There are over 1,100 species of bat worldwide, and we have 17 resident bat species in the UK. Some of which we know we have at Sheepdrove, but until the whole area has been analysed, we won’t know how many species we support here for sure.
In the woodlands and along the field margins there are common sightings of Common Pipistrelles and Soprano Pipistrelles. These tiny bats are very vocal, and are the easiest to pick up with a bat detector as they hunt insects. The Common Pipistrelle consumes over 3,000 small insects a night!
Easier to spot flying but much harder to pick up with a detector is the Brown Long Ear bat, easy to see why this bat has this name, because it has ‘Dumbo’ ears. This bat is an audio specialist, even detecting insect foot falls on leaves with its highly tuned ears.
There have also been recordings of Natterer’s bats in the woods here. These medium sized bats are slower fliers than the Pipistrelles and because of their broad wings, they are able to manoeuvre through foliage, plucking larger insects off as they fly. They even take spiders from webs. Because of the prey size, Natterer’s will usually stop to eat their prey, rather than consuming on the wing.
Sheepdrove also has Serotine bats, this is one of the UK’s largest bats, and it has a relaxed and leisurely flying technique. It favours small flies and moths, and is one of the first to emerge in the evening.
Where there is water and tree cover like many local rivers, streams, lakes and canals you might be lucky enough to come across a Daubenton’s Bat, a water specialist, which skims its insect prey off the water’s surface with specially adapted membranous tail and large feet.
There have been a few sightings of this bat at Sheepdrove’s lake and reedbed system, and it’s always a delight to see these bats hunting just fractions of an inch above the water’s surface.
All of our UK bats are insect eaters, and use echo location to catch their prey. Echo location works by creating an ultrasonic noise, which is emitted from the bat’s larynx (voice box), and then listening for an echo when the sound waves hit their target- in this case an insect. When the sound waves deflect, they are detected by the bat. The bat then knows where their prey is, and how big it is. By emitting almost constant calls, the bat can pinpoint the insect’s whereabouts with unerring accuracy.
It is unfair to say that bats are blind. They can see, but their ears are of much more importance to them for echo location, so their eyes have not developed very well.
The best time to spot a bat is at dusk as they emerge from their day time roosts to start the evening hunt. On a warm evening walk into a wood, find a clearing and stand and watch quietly. If you’re lucky, you’ll start to see darting black shapes moving in and out of the fading light.
Top photo by Jason Ball is probably a Serotine bat.