Batty about bats
Post categories: Springwatch,Ìýbats
| 14:37 UK time, Wednesday, 3 June 2009
Bats were recently featured on Springwatch when the team here managed to sync up the thermal imaging cam with a device that recorded the sound of the bats echo locating, so it was audible to our ears..
Bats use echolocation - a series of short, high-pitched sounds in order to hunt and find their way around in the dark.
Sounds travel away from the bats bouncing off objects and surfaces in the animal's path creating an echo.
This echo then returns to the animal, giving it a sense about what is in its path whether it be a gnat, an owl or even a tree. This is exactly the same technique used by whales and dolphins to hunt fish.
The high speed, blur of colours and high speed maneuvering reminded me of tie fighters fighters defending the death star.
Now for the science part...
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(In this clip, the pipistrelle bat comes first, then at 1m41s in, we switch to the Daubenton's bat)
Bat echo location occurs at extremely high frequencies, inaudible to us humans so it was a treat to be able to see them flying around buzzing their prey in the pitch dark but also to hear them.
Our hearing ranges from approximately 20Hz (cycles per second) to 15,000 to 20,000Hz (15-20Khz) depending on our age, but bat calls are generally well above this.
The tiny pipistrelles appeared first at around 9pm flying high up under the leafy canopy. Look out for these in your garden at dusk tonight.
They echo locate at around 45Khz and as you'll hear in the audio clip, making a buzzing noise when they finally snaffle their prey at close range. They continually bounce sound waves off their target, getting closer and closer until finally making contact.
It sounds a little like a fly being electrocuted in one of those fly traps you find in a fish & chip shops!
They scoop the insect up with their feet and feed themselves on the wing, similar to our red kites at Gigrin Farm.
The Daubenton's bats are slightly bigger and operate at around 40-90khz and unlike the pipistrelles, fly directly over the water grabbing midges as they go and spinning in tight circles, akin to a dog chasing its tail at warp speed! They will even take prey directly from the water's surface.
Gull
Links:
Bat videos
Bat species guide
Pipistrelle bats on ³ÉÈË¿ìÊÖ Wildfacts
Daubenton bats on ³ÉÈË¿ìÊÖ Wildfacts
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