A nocturnal walk along the Wensum Way

Our next walk saw us visiting the lovely All Saints Church in Swanton Morley on Saturday 20^th of June 2015. Built in the 1300s, All Saints is a grade I listed building, located close to the Wensum Way. It has had a long history with bats, with a maternity colony of Natterer’s bats using the building, and has been involved with recent research looking into ways to implement techniques, that will provide a solution for churches affected by large bat colonies, without causing undue harm to the resident bats.

At 21.00, we welcomed 7 people plus 2 volunteers, Laura and Jamie. As the sun began to set, we headed down to the Wensum Way, a Norfolk County Council Trail, aptly called the ‘River Walk’ by the locals. Taking us into a beautiful Norfolk landscape consisting of open pastureland, hedgerows, and fragmented woodland, it looked like promising territory for our walk.

Around 10 minutes into the walk, we heard our first bat, a Noctule. Looking up we saw 2 Noctules flying above our heads (Noctule prefers to fly in straight lines high up above the tree line, over open habitat), followed shortly by a few others. Seeing these many Noctules, indicated to us that their roost was probably nearby. Noctules tend to roost in trees, particularly ones that have old woodpecker holes. We then heard our first pipistrelle, a Soprano Pipistrelle, one of our smallest bats weighing between 4- 7g.

Learning how to use a bat detector © Norfolk Wild Nights, Sonia Reveley

Progressing towards the River Wensum, we looked back towards the church and we were rewarded with a view of the sunset lighting up the sky with flashes of red, yellows, and gold. This view was in stark contrast with the sight we saw when we arrived at the side of the river, a darkening horizon and mist rolling into the fields. It was here that we heard and saw our first Daubenton’s bat, a Myotis species that prefers water habitats and is aptly nicknamed ‘the water bat’. Having satisfied ourselves with listening to Daubenton’s and Soprano Pipistrelles by the riverside, we started our journey back to the church and heard our first Natterer’s, most likely part of the colony exiting from the church. In addition, we also heard some Common Pipistrelles as they flew along the hedgerows.

On arriving back to the church faced with the possibility of getting caught up in the impending rainstorm, we quickly checked the moth trap that we set up earlier. We found a Straw Dot, Small Magpie, Heart and Dart and 2 Dark Arches. Afterwards when packing up the equipment we also found an Elephant Hawkmoth and a Figure of Eighty moth.

Moth trapping © Norfolk Wild Nights, Sonia Reveley

The Small Magpie is a micro moth, part of a group of smaller moths regularly caught in moth traps. This moth is common and widespread and has distinctive black/grey markings and yellow body parts. It flies around in June and July, so now is the best time to find them in your trap. It is found in gardens, woodland, fens, heathland, grassland, and scrub. The larva feeds on nettles and occasionally woundwort.

The Figure of Eighty is a quite a distinctive moth. It has a white ‘80’ mark on its forewing, which gives it its name. It flies around from May to July and is found in woodland, parks, heathland, grassland, and gardens. The larva feeds on aspen and poplars.

Thank you all for coming along. Your support for the project has been much appreciated.

Another walk will start at All Saints in Narborough, on Saturday 11th  of July, 9pm

We are running another walk on the 4th of July, this time from All Saints, Besthorpe.  We hope to see some of you there. 

Norfolk Wild Nights first 2015 walk

On a mild overcast evening of Saturday 13^th of June we ran our first 2015 Norfolk Wild Nights (NWN) event. Having rained on and off pretty much all day, we were worried that the walk was going to be a wash out. Fortunately, for us the rain stopped and though it was overcast, it was still mild enough for us to run the walk.

 For this gentle amble, we used St Marys Church in Earlham, near the University of East Anglia (UEA) as our hub to start from. 14 people joined us for the walk, from members of the church, to Norwich residents and students from UEA.

Beginning with an introduction on the types of bat species that can be found in the UK, we then described two different bat detectors. Bat detectors are an essential kit when looking out for bats. Calls made by bats when hunting and navigating are too high pitched to fall within our normal hearing range, so we can’t hear them. A bat detector transforms these echolocation calls by lowering the frequency of the sound to something we can hear.

First detector presented was the Batbox Duet, a heterodyne detector, which is tuneable. It allows us to select different frequencies and listen to various bat calls. With practice over time, your ears will pick up the different tones, clicks, and slaps, aiding your identification. Unfortunately with this detector, you can only tune in to one frequency at a time and therefore might miss other bat species that may be flying around. However, the duet can be combined with a MP3 recorder and will then act as a frequency division detector, which will record all sound across the full frequency spectrum.

Second detector introduced was the Anabat, a frequency division detector, which captures the full frequency range and records sound continuously onto a SD card, so bat calls made by different species are unlikely to be missed. The sound files stored on the memory card can be analysed later using sound analysis software called Analook.

Introductions over we then equipped everyone with a bat detector, a head torch and a bat field study council guide (FSC). First we checked out the grounds of St Marys Church and were lucky enough to hear a few Pipistrelles flying around the churchyard. We then headed across Earlham Park taking a gentle stroll alongside the River Yare, stopping at various spots by the riverside, where we heard and saw Daubenton’s and Soprano Pipistrelles. We continued to cross the park heading towards the Sainsbury Art Centre, where our moth traps had been set up ready for our inspection. Along the way, we continued to see and hear Common Pipistrelles, Soprano Pipistrelles, and Daubenton’s, including a Noctule at the bridge close to the Sainsbury Centre.

A sonogram of a Noctule bat recorded on a SM2 and analysed on Sonobat. The deepest and clearest calls of the Noctule are best heard on the peak frequency of 20kHz (frequency range 20 – 45kHz). 

On reaching the Sainsbury Art Centre, surrounded by bats flying overhead in the clearing in the canopy, we found a few moths in our moth traps from the Common Pug to the Snout, which we were able to pot up and bring out so that everyone could get a closer look.

We then headed back to St Marys Church, where thanks to the churchwarden we were able to gain access to the inside and have a quick look at the interior.

Altogether, a successful night with 4 species heard during the evening and a good turn out. Thank you very much to everyone who came along.

More information about bat detectors can be found on the Bat Conservation Trust website. http://www.bats.org.uk/pages/bat_detectors.html