Saturday, 2 May 2009

Batbox bat detector

After work on Thursday we went up to the wood to cut some logs to length to make a raised bed at home to grow vegetables in, but also took the opportunity to take the Batbox bat detector we've borrowed from a friend and stay until dusk to look for bats.

First though, I need to tell you about the new stuff that's growing. Out in the wayleave the broom is now flowering, which must be a treat for the insects:
Inside the wood the chestnut is coming on well, though it still has a long way to go:
The oaks are also beginning to thicken their canopies:
We noticed something exciting about the oaks. We'd been told a year ago that when we thinned the oaks that the ones left would grow to fill the space over a period of time, and here's the start of it:it's not just in one place, it's right up the tree, on all the trees:
Also, in the gaps left on the ground due to the thinning and coppicing, there's grass springing up where before there was bare earth:
The bluebells in our wood have finally caught up with Sweep Wood, which gets a bit more light:
We also saw this strange bug. Some kind of caterpillar perhaps?Anyway, once we'd had a look around and loaded up the logs we were taking home, we sat down with a hot drink and waited for dusk. (I took this photo of the kelly kettle using a 6 second exposure, taking advantage of the new tripod and wireless remote control I bought for the camera)
Here's the bat detector:It works by converting the ultrasound frequencies of the bats into something we can hear. There's a dial you can tune to pick up different frequencies (20-120 kHz), allowing you to identify different bat species - though we're not expert enough to do this! Here's a little video of me testing it with some keys (jangling keys emit ultrasound!), and then recordings of a couple of bats:

Next post coming up - making the raised bed we took the logs back for.

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