Bat walk - May 2011

On the evening of Friday 20^th May 2011, Society members joined the Bedfordshire Bat group (BBG) on a guided batwalk in Priory Park, Bedford.

 The Bat-Group provided us with bat detectors that respond to a range of frequencies between about 10 and 120 KHz, converting them to audible frequencies.

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Starting at 9pm, we visited a newly re-roofed building that had previously housed a roost of 180 Pipistrelles, but were disappointed to find that , as yet they have not re-colonised the roof. There were plentiful speckled bat droppings on the wall below the opening, but no bats in residence. 

This was where we had our first encounter with a Noctule  (Nyctalus noctula) zooming overhead and registering at about 20-30KHz – a strong loud signal.  The Noctule was feeding above the trees swooping,  dipping and diving, we watched it against the darkening sky. We then walked back to the path beside the main lake and here were entertained by Pipistrelles [Pipistrellus pipistrellus, Common Pipistrelle (42-47 kHz) and Pipistrellus pygmaeus, Soprano Pipistrelle (52-60 kHz)] feeding just below the canopy and just above head height. The bat detectors were sounding in all directions. They had a more  ‘fluttery’ flight pattern buzzing towards us in one direction then turning rapidly to make another traverse of the insect rich air. 

Turning off this path we went towards the Finger Lakes, by this time torches were needed to prevent tripping over the tree roots in the dark. At the lakes we saw Daubenton  bats (Myotis daubentonii) sweeping low over the surface of the water from which they scoop insects. Their call registers between 35 and 85 KHz. We could see them as well as hear them because the park warden made periodic sweeps over the lake with a flashlight catching the bats in their low, steady flight paths. At this point there were Daubentons,  Pipistrelles and Noctules in evidence, each feeding at its own preferred elevation; a good example of niches being occupied. The noises from the bat detectors helped us to know which bats were around by the frequency and pattern of clicks, ‘slaps’ and ‘chip-chops’.

By now it was 10.30 p.m. and we made our way back to the visitor centre where we thanked the guides for the very interesting evening, returned the bat detectors and made our way home.

Thank you to  Bob, Danny, Jude of the BBG and Viv of SB and BBG.

If you would like to visit this very bat rich site then if you follow road signs you will end up the wrong side of the lake so the address Barkers Lane is vital to get you to the correct place.

The postcode is MK41 9SH, and the grid reference is TL072493

 "sat nav” using the post code will lead you to the correct location

Images from Wikicommons