Friday, 11 June 2010

Cwm Rheidol Sopano Pipistrelle count, last night's report, and other interesting things!

Good day everyone, hope you're all rested after last night's outing, thanks to everyone who came and made it a great evening. I hope you all enjoyed yourselves and learnt loads.

The head count was only 254, which is a bit disappointing to tell the truth - not up to our usual numbers. It was a bit windy but not enough to keep bats from coming out if they were there. The other notable thing is that they emerged from the front elevation of the building and not the side as they have done for the last few years. It could be that the cold winter has upset thing somewhat. I just hope there are a few more next time - we've got three more counts to come, 21st June and 5th and 19th July.

According to BCT, our pip site, with a peak count of 949 (2003), is the 6th largest soprano pip colony in Wales, out of 35 counted for the NBMP since 1997 and is the 19th largest in the UK out of 330 counted. The over all trend for pip across the UK however is down since 2003 unfortunately - the weather perhaps, it's getting the blame for so much lately?

Pips, as you may know, are divided into two species, the sopranos which echo locate at 55 kHz and the common at 45kHz. So how can you tell them apart you may ask. Well here's how you do it according to BCT.

Pips make their most distinctive sounds when flying in open space, so when trying to work out which is which keep this in mind. Always use headphone and when the pip is heard, quickly tune the dial between 37 and 60 kHz, Do not look at the dial whilst you are doing this. As the dial is rotated, listen until you hear the loudest sound, which is described as 'slap'. At this point you are close to the optimum or peak frequency. Then continue rotating the dial close to this frequency and listen until the sound is at its DEEPEST note (not the loudest part of the sound). When you are tuned to the deepest note, look at the tuning dial and record the frequency. If you are trying to identify bats from a roost repeat this process several times to get a spread of readings. If you are conduction a field survey remember to keep counting the number of passes too. All very simple, easy when you know how! Above 52 kHz record as a soprano pip (55kHz), between 42 - 48 kHz record as a common pip (45kHz). To complicate things, anything below 40 kHz consider as a Nathusius's pip or if the deepest note is heard at 49, 50 or 51kHz, record as pip spp.

Now you know so we'll have test next time but don't expect me to know will you!

Good luck tonight with the Brown Long Eared Count. We'll do it all again next week. We've also been asked to repeat the BLE's twice more in July, if we get time so there will be plenty of opportunity for everyone to come along there too.
Happy Batting

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