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| Go on then tell me it wasn't http://www.lbcarchive.co.uk/forum/viewtopic.php?f=7&t=6265 |
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| Author: | Bob Barker [ Wed Sep 12, 2007 1:45 am ] |
| Post subject: | Go on then tell me it wasn't |
Went for a stroll with my bat detecter round Corus fishing pond tonight (grid ref TA 903 122) It started off a warm, bright, still evening but without much insect activity - only got bit twice - but then a stiff breeze kicked in which brought the clouds - couldn't stay too long though - the pubs insist on shutting at eleven. Lots of hits but most were fleeting and seemed distant. Seven close calls were within 45 - 55 khz range but one wasn't -almost sure it was a Noctule - but I couldn't swear to it - I can recognise a pipistrelle but not much else Field markings are it was dark coloured and it didn't half shift. Regards Bob PS Am I the only one interested: or don't we bother recording the common species I'm only asking cos I saw a rabbit today and I was thinking of logging it in PPS When did Long tailed field mice become Wood mice and why are they living in my kitchen - three floors up a block of flats |
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| Author: | Nick Tribe [ Sun Sep 16, 2007 4:01 pm ] |
| Post subject: | |
Hi Bob Can't help you with the rabbit and mouse queries and I'm not sure what I can bring to your bat query, but here goes anyway! What did the bat sound like? Keeping it straightforward - pips make a 'smack' or 'slap' noise, myotids (Daubentons, Natterer's, Whiskered and Brandt's) make 'tick' noises (usualy at a much faster rate than pips) and noctules make a 'chip-chop' noise (longer calls delivered at a much slower rate than either pips or myotids. What frequency was the sound loudest at? Common pips are loudest and deepest in tone at 45kHz or so, 55kHz for soprano pip. Myotids have a very wide frequency sweep that starts above 80kHz (over 100kHz sometimes) and goes down below 30kHz. They don't really have a loudest frequency, their calls sound pretty much the same all through their range. Noctules are loud and peak in volume and are deepest in tone about 21/22kHz although they will often create harmonics that are found in the 40s. Where was the bat flying? Pips and myotids typically feed between water level and 2-3 meters above, noctules are large bats and typically fly straight(-ish) at tree-top height with dips down as they pursue prey. 'Dark coloured and it doesn't half shift' covers all British bats and I dare say most in the world. Useful advice on using bat detectors and bat call examples at http://www.bats.org.uk/nbmp_tutorials/detectortips.htm Nick |
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| Author: | Bob Barker [ Sun Sep 16, 2007 8:02 pm ] |
| Post subject: | Thanks Nick |
Thanks, with the information you've given me I going to tick off a noctule. It definately was a slowish tick-tock sound but I had the detector in frequency division mode and by the time I'd switched the bat had flown out of range and I couldn't pick it up again, so I don't know what frequency it was at Unfortunately my eyes aren't good enough to see a deal in semi-darkness so that's about all I see, as you say - not a lot of use Thanks Bob |
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