BCT Bat Conference 2013

This year’s National Bat Conference, organised and run by BCT, was at Warwick University last weekend. The conference is always held in September and I always come away with a mixture of enthusiasm and regret – it’s a great opportunity to chat to other bat workers, both volunteers and consultants, and listen to some fascinating talks which really inspire you… but it is held just as the main bat season is drawing to an end and there is little time left to go out and carry out the surveys which the conference inspires! I have certainly come away with a few ideas for next spring.

Serotine bat in the hand

Several of the talks this year could be grouped broadly into the ‘state of bats’ category. This included the opening talk by Julia Hanmer, the chief executive of BCT, who outlined the work which BCT have undertaken in the last year with a special focus on the work being done to help churches with bats find solutions which allow both to coexist. Lincolnshire Bat Group’s own work in Tattershall Church was held up as a particular example of how the bats could live happily alongside the congregation with input and guidance from experts and this topic was taken up and explored in more detail later in the programme by Laura Bambini who has been been working alongside church wardens and congregations to find out the ways in which bats do genuinely impact upon the running of a church, and what information and support can be provided to alleviate these concerns. This positive work was set sadly against a backdrop of the general anti-environmental ethos of the current government, with Owen Patterson’s name being rightly greeted with boo’s and hisses by a conservation-minded conference congregation. The fact that the Chief Constable who leads on Wildlife Crime is openly anti-bats was another shocking revelation and goes to show just how much prejudice we need to work against.

Pete Charleston heads up the BCT investigations unit and took the stand for the next talk. BCT and Pete in particular are doing great work to combat wildlife crime relating to bats, with regular increases in numbers of referrals and numbers of prosecutions. We are sadly let down at present however by the prosecutors themselves; a recent case where a developer knowingly destroyed six bat roosts and was fined just £35 per offence is grossly disproportionate to the crime committed and serves to send out entirely the wrong message to those who view the protection of our native wildlife as an impediment to their own economic gains – a mantra perpetuated by George Osborne in his recent attacks on protected species legislation.

Leaving politics aside, and on a much more positive note, Lisa Worledge and Helen Miller gave a talk later in the morning on the current research on Pseudogymnoascus destructans in Britain and Europe. This is the fungus responsible for the deaths of huge numbers of bats in hibernation roosts in the USA and there is a fear that the pathogen could cause similar destruction to our native species. The talk concluded that there was cause for cautious optimism that the bats in the UK had in fact co-evolved alongside this fungus and were therefore relatively unaffected by it. The basis for this is the identification of the fungus in environmental samples from across Europe and in the majority of hibernation sites surveyed in the south of England in a recent pilot study, as well as the positive identification of the fungus on a hibernating bat for the first time in the UK, yet without seeing the same devastating effects which are associated with the fungus in the US. The genetic diversity observed in the fungus across Europe suggests that the pathogen has been present and has developed into differing genetic strains across its range, whilst the homogeneity of the fungus genome in the USA suggests a much more recent introduction. The fact that this fungus appears to be novel in the USA would explain why the bats there are being so badly affected in the same way as a new flu strain can strike down half the country. The risk of the disease blighting our UK populations has been cause for concern for a number of years now, and cautious optimism is certainly a better outlook!

The importance of bats within an ecosystem, and the risk of losing such an important species, were highlighted in a talk by Ryszard Oleksy who has been undertaking work on the role of the Madagascar flying fox on forest regeneration in Madagascar. This is a large fruit-eating species, very different to our tiny insectivorous UK species, but the importance of the genera on an ecosystem scale is likely to be similar. The study found that 110 plant species are included within the diet, that seeds which have passed through the digestive system germinate well and that the distance which an individual bat can disperse seeds is significant. The species makes a very effective agent of forest regeneration, linking up isolated forest patches in a fragmented landscape and assisting in the dispersal of a number of endemic plant species.

One issue which is well known to most bat workers now is the risk which breathable roofing membranes (BRM’s) pose to bats roosting within buildings. Bats can easily become entangled in many of these membranes and there are reports of over 100 bats being killed by becoming trapped and dying of dehydration or exhaustion, and yet they are put into new roofs on an almost routine basis, including roofs where known roosts may be present. Stacey Waring gave an excellent talk on her research into this issue, combining a more abstract lab-based tests of the extent to which different membranes on the market become ‘fluffy’ and as such, of risk to bats; with tests of how the membranes performed with captive bats within a rescue centre. All of the membranes tested were found to pose a risk, compared with traditional bitchumen felt, although there is hope that the findings of this study may feed into the design process and more bat-friendly materials may become available in the future.

Geoff Billingham gave a talk on Wolvercote Tunnel in Oxford, outlining the results of a range of surveys and a concept of mitigation designed to ‘flush out’ bats from the tunnel in advance of an oncoming train to avoid them being killed. This relied upon lights being turned on in the centre of the tunnel a few moments before the arrival of a train, and then progressing out to the peripheries with the hope that bats would move ahead of the advancing light. The most concerning figure within this talk, to my mind, is the 5 dead or grounded bats identified in 21 visits to the tunnels. Trail cameras also identified an average of three visits per night from species such as foxes or cats, which would scavenge a bat carcass, making it unlikely that a dead bat would remain for a long time. This rate of killing is significant, considering that the tunnel is 130m long, the trains run at 30mph and they do not run much beyond 10:30pm. If this number of bats are killed in a single tunnel, the number which must perish across the country is highly significant and is likely to have a serious impact upon populations. It also puts into perspective the potential impact of new technologies such as wind turbines, when viewed in comparison with more established and accepted threats which may be of much greater significance.

Four talks over the weekend discussed the ways in which we can increase our knowledge of the distribution of bats within the UK.

Two focussed on islands – the first of these was studying the distribution of rare woodland bats, specifically Bechstein’s and barbastelle – on the Isle of Wight. Ian Davidson-Watts sampled in 42 different woodlands across the island and used mist nests and harp traps to catch bats and radio-tag them. Two thirds of the woodlands were found to have Bechstein’s present – this is one of the Myotis species and one of the rarest species in the UK – and a number of maternity roosts were subsequently identified. The surveys also identified potentially the largest barbastelle roost within the UK with over 115 individuals counted out. These findings make the Isle of Wight of potentially international significance for rare woodland bats at a landscape level.

Moving to the opposite end of England, Hugh Watson discussed static detector surveys on three islands off the Northumberland Coast to identify the species present. This is an under-recorded area and a total of five species were recorded on the islands with evidence of bats commuting to forage from the mainland.

Two further talks discussed mass-participation bat surveys where a large number of the general public were encouraged to get involved, to learn more about bats and to extend the coverage of bat records within a county.

The Norfolk Bat Survey set up a number of ‘Bat Monitoring Centres’ across the county so that everybody was within 15-20 miles of a station. The public could sign up for the survey and then pick up a static detector which would be put out at a number of locations within a 1km square and left to record the bats which went past. This has enabled bat records to be obtained for a large area of the county, and allowed interested individuals to find out which species fly through their gardens and their local landscape when darkness falls.

The Somerset Bat Group by contrast have designed their Big Bat Survey – a number of transects across landscapes within the county, including the Blackdown Hills and the Mendips, where a group of at least four people would be equipped with bat detectors and would walk the set routes to find out which species were present. Fifty and seventy members of the public took part in the respective surveys, and the results were again invaluable in increasing the knowledge of both the distribution of species within each area and their use of the various habitats present.

The last two talks focussed on technological advances in our approach to bat surveys. The first of these was a talk by John Atanbori of Lincoln University who is using computer vision techniques to automatically pick out bats from a video taken in low light levels and compute metrics such as wing beat frequency, with an aim to using this as a tool for species identification. The characteristics of bats in flight differ between species to a greater or lesser extent, as anybody who has watched the rapid wing-beats of a foraging pipistrelle alongside the broad-winged fluttering of a brown long-eared will know. The project is a work-in-progress but offers a fascinating new avenue of species identification if it can be developed.

The final talk was given by Ian Agranat of Wildlife Acoustics on their latest classifiers for UK bat calls. The aim of this software is to identify a bat call to species level (or genus level in the case of the myotis bats) without a bat worker needing to scan through every single call. The need for this technology is increasing as the price, availability and usefulness of static bat detectors is growing – these provide very cost effective monitoring of a site compared with human surveyors, but they do produce huge amounts of data which needs to be sifted through. The Wildlife Acoustics technology uses machine learning where a large number of identified calls are fed into the software and the algorithms identify differences which split the sound files up by their respective species. This is successful at an 80% accuracy which would significantly speed the process of analysis, whilst still at this stage requiring a certain level of operator confirmation and amendment. It is another exciting avenue of development and another ‘watch this space’.

Workshops were wide-ranging as usual and it is always a shame that you can only pick one or two. I opted for the tree roost field survey workshop with Henry Andrews taught me a number of new things as well as re-enforcing many others with examples and photographs which were invaluable, even after a summer spent up trees and inspecting potential roost sites. In case you haven’t come across his Bat Tree Habitat Key – you can view it for free on his webpage. The key to extending and refining this already invaluable piece of work is to gather more records – calling anybody working on bats and trees to contribute! On the Sunday I opted for Jon Whitehurst’s talk on an Introduction to Species Distribution Modelling – a last minute switch but one which has me itching to try out the techniques he outlined to model bats’ use of the landscape.

As I said at the outset, the only downside to the conference to my mind is that it is at the end of the season and so all of these great ideas and enthusiasm to get out there have to lie dormant through the winter until the spring when the bats come out of hibernation and the survey work can begin again.
Next year’s conference is due to be held at Warwick University again and you can find out more on the BCT’s website here and the BCT blog on the conference proceedings is to be found here. There are photographs from the conference on the BCT’s facebook page here, including the customary after-dinner Ceilidh!

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Harlaxton to Woolesthorpe – a 9 mile walk via woods, water and Vikings

For something a little bit different, I thought I would share a walk which is one of my favourites in the area. It starts from the village of Harlaxton to the west of Grantham and takes you out across farmland, through woods, around Denton Reservoir, follows the canal for a while as well as a taking in stretch of the ancient track – the Viking Way. Best of all, the mid-way point of the walk has a choice of two different pubs where you can stop for lunch!

The walk is 9.3 miles in total and can be shortened in a few places if you consult an OS map. This includes cutting up the Viking Way to avoid the village of Woolesthorpe (and both of its pubs!) and starting in Denton rather than Harlaxton.

The numbers on the instructions relate to the map. I have also put in italics a few points of interest along the way.

Harlaxton to Woolesthorpe Walk Map
Harlaxton to Woolesthorpe Walk Map

I hope you enjoy this walk and that all the instructions are clear – let me know if you try the route out and anything interesting you see along the way!

Point 1

Start the walk in Harlaxton village – there is a layby where you can park opposite the medieval monument and phone box which are just beside the village shop. To reach the starting point from the A607, turn left into the main village (if you are coming from Grantham) and follow the road round until you find this location.

To begin the walk, head back up towards the A607 on the High Street.

As you pass the shop, you can see a field on the left-hand side which is an old orchard often grazed by a diminutive pony. There are often interesting wildflowers such as greater celendine to be seen along this edge in the summer months, as well as spring flowers such as forget-me-not earlier in the year.

Point 2

When you reach the A607, turn left and walk west for a few minutes until you reach the see a wide layby on the opposite side of the road. At the nearest end of this, you will see a metal gate and a footpath sign pointing you north along a track signed Peashill Lane. Take this track, being careful to close the gate properly behind you, continue past a farmstead and follow a rough track down a gentle slope.

There are a number of old ash trees lining this track as well as interesting wildflowers with the purple flowers of common vetch and black knapweed on the verge mingling with more arable weeds such as pineapple mayweed and field poppies on the edge of the crops.

When the footpath forks to the left or the right, take the right to do a slight kink but continue down towards the canal in the same direction as previously.

Point 3

On reaching the canal, turn left through a gate and head diagonally across to the opposite corner of the field where you will find a gate allowing you onto a wooden footbridge over a ditch.

This field is a great spot to see fieldfares and redwings which migrate into the country in the winter time and can be seen from around October onwards. They forage in the open countryside and will quickly strip the remaining red and purple berries from hawthorn and blackthorn.

Point 4

Having passed over the ditch, continue straight ahead to the right of the hedgerow before you until you pass over a stream and up a set of steps to reach Denton Reservoir.

Denton Reservoir is one of the best spots for waterfowl in the area – many species such as mallards, great crested grebes, coots and moorhens can be seen all year round but are joined by large numbers of tufted ducks and pochard during the winter. You might also spot cormorants and herons on this waterbody.

The reservoir is favoured by anglers and you might be lucky enough to spot species including pike and perch if you keep an eye on the water as you walk around.

At night, this is a great spot for bats with Daubenton’s and soprano pipistrelle foraging across the water. They can be best seen during a visit around half an hour after sunset on any warm evening between May and September. The much larger noctule bat flies high over the hedgerows and field edges which run around the perimeter of the reservoir, hunting insects on high rather than taking those which arise from the water.

Walk to the right around the edge of the reservoir, taking care as there are no rails or fences, until you reach a path which drops down to your right in a gentle slope to bring you to a little brook which leaves the reservoir here.

Point 5

Take this path down and then follow the brook away from the reservoir until you reach a point where the path turns left or right. Take the path to the left. Quite quickly, when the woods end on your right hand side, turn right along the boundary between the trees and the field.

Walk along the woodland edge for the length of a field, then pass into the next. Here, cross the field diagonally along a well trodden path until you reach a small carpark area and a bridge which passes over Grantham Canal.

Point 6

Cross over this bridge and then turn left to follow the tow-path of Grantham Canal as it winds through the landscape.

Grantham Canal
Grantham Canal

The canal is an excellent way to ‘reveal’ the landscape it passes through. It was built to be as flat as possible, to minimise the need for locks, cuttings or embankments. With this in mind, the meandering route and wide loops which the canal takes reveal quite subtle undulations in the landscape, as well as more prominent landforms. As you leave the bridge, you will notice a wide loop which the canal takes around a field and, looking back, you notice the way that this farmland rises up.

You will pass under 3 more bridges as you proceed. The first is the road bridge for Casthorpe Road which links Denton and Sedgebrook. The second is an old canal bridge similar to the first which you can take left to follow the Viking Way up Brewers Grave – this route will take you all the way to Oakham to the left or Hull to the right. The third is a small footbridge which takes a footpath up to the road between Denton and Woolesthorpe.

The hedgerows which flank the towpath to the right provide a feast of blackberries and sloes in the autumn. There are also hawthorn berries which are also edible although not entirely pleasant in my experience!

If you look to the water, you can often spot shoals of juvenile fish including roach and dace as well as their larger parents further out into the channel.

Dragonflies and damselflies are to be found in abundance along here in the summer right through to September. The dragonflies are usually much more substantial, and hold their wings out flat when at rest, as though they were soaking up the sun. Damselflies, often an iridescent blue, hold their wings together, as though they were making themselves as unobtrusive as possible.

Walk along the canal until you pass the locks and reach another bridge, just before the pub.

Point 7

Cross the bridge just before the Rutland Arms (or the Dirty Duck depending on your preference).

The pub does good standard pub food and offers a range of ales and other drinks for refreshment – a stop on one of their canal-side picnic benches is often a welcome rest at this point. This pub can get very busy, especially on nice days, so bear in mind that there is also another pub at Point 8.

Then follow the track away from the canal up to the road where you will turn left towards the main village of Woolesthorpe. There is a pavement along this section. Cross and continue in the same direction when you reach a crossroads and turn left when you reach Worthington Lane.

Point 8

Walk up Worthington Lane until you come to a second pub called The Chequers.

The Chequers offers a slightly more refined fare than the Rutland Arms – think ciabatta rather than sandwich! They also do a good range of drinks and there is a large beer garden at the back which is always a pleasant place to sit for an hour or two.

If you walk past the frontage of the pub, you will see a very optimistic cricket pitch ahead of you – walk down the right-hand side of this until you reach a stile. Cross the stile and head up the hill, keeping the woodland on your left hand side.

This is a steep section but offers fantastic views back across Woolesthorpe and out across the Vale of Belvoir. You can see just how flat the land is all the way out to the Trent to the east. Straight ahead, you can see Belvoir Castle on the top of the hill.

View from the top of Woolesthorpe Hill
View from the top of Woolesthorpe Hill

Point 9

When you reach a stile on your left hand side, go through it and follow the footpath past an area of recently cleared woodland. When you reach the road, turn right and follow it to a bend. This section does not have a pavement and cars can travel quite fast along it so walking on the wide grass verge is recommended! Luckily the walk only takes a minute or two.

Point 10

When you reach an s-bend in the road, you will see a house on your right and ornamental gates which lead into the Belvoir Estate. On your left is a track which takes you down to the canal – this is where the bridge we encountered along the canal would bring you to. Instead, we want to take the track to the right which takes you away from the canal and through an area of young woodland. This is the Viking Way.

The track winds along between arable fields, bordered by hedgerows with sweet chestnut trees as standards all along. If you like chestnuts, it is well worth bringing a bag along to fill if you are planning a walk along here in late September or early October.

The ease of walking along here does vary, depending largely on whether the various 4×4’s or trail bikes have been obeying the signs and keeping off. The restrictions on them vary but they are often permitted to use the route at certain times of the year when the disturbance and damage they cause can be enough to make it tough going for much of the rest of the year.

Point 11

The track will soon reach a railway bridge and a row of houses will appear just afterwards on the right hand side. Cross over the bridge and turn immediately left to drop down the bank and follow the path of the old railway to the left.

You will pass a damp pine plantation to the left where woodpeckers can often be heard drumming on the trees or cackling their cry. On the right hand side soon after, you will pass a lake where you might be lucky enough to spot a heron stalking the shallows.

On the approach to a second bridge, where we leave this section, you will see a lot of young ash trees lining the sides of the old railway line and forming a light canopy over the track. Ash is a relatively quick growing species and often colonises abandoned locations such as this. Walking along this section, take a moment to consider how different the landscape would be if ash were to go the way of English Elm as a result of Ash Dieback disease.

View across the fields to Denton Church
View across the fields to Denton Church

Point 12

When you reach another bridge, take the track which brings you up to the right of it, just before the bridge itself, and come back out onto the road. Turn right and follow the road down and into the village of Denton. Again, we are on a stretch of road with no pavement and potentially fast cars so do be careful for a few hundred metres until you reach the pavements which carry you safely through the village.

As you enter the village, just beside the Denton sign, there is a patch of butterbur on the left hand side. The great wide leaves and tall flower spikes look rather prehistoric and are very noticeable in May when they are in flower. This is a species often associated with wet habitats and the stream which passes just beside these plants explains their position here.

As you pass through the village, you will see the village hall on the right hand side. This is one of the buildings from the WWI encampment at Belton Estate during the war when a machine gun training ground was located there.

The road will bend left, then shortly right to head uphill towards the A607. Walk along until you see a footpath sign indicating you to turn off to the left.

Point 13

Follow the footpath down a narrow jitty between two hedgerows and out into a field. Walk ahead and slightly right to cross a stream at the bottom of the field where there is a bridge to the right of dense willow. There are often cows in this field so be sure to keep dogs on leads.

As you enter the field, take a look to the left where you can see an impressive old oak in a private field behind the houses as well as a beech on the field boundary.

After crossing the stream, head back uphill to a stile which opens onto a track.

Point 14

Turn right along the track for about 20m, then leave it again over a stile to your left. Follow the path diagonally across the field to reach a gap in the hedgerow at the far corner.

If you look to your left as you walk, you can see the canal which you just walked and another nice view out across the Vale of Belvoir.

View from the A607 - the ladybird balloon is a familar sight on nice summer's evening across the Vale of Belvoir
View from the A607 – the ladybird balloon is a familar sight on nice summer’s evening across the Vale of Belvoir

Go through the gap, (carefully!) cross the A607 and go straight over the stile into the field opposite. Then take the track diagonally to your left to cut off the corner of the field and reach a gate which will bring you back into the village of Harlaxton. Walk through the two gates and then continue along the road which the footpath becomes.

Point 15

When you meet another road at a T-junction, instead cross over and go through a gate into the field. Cross this field along the footpath and go through two more gates to bring you out into the churchyard of Harlaxton Church.

Walk across the front of the 13th Centuary church (look out for the gargoyles as you go) towards a large copper beech.

This is recorded in the Woodland Trust register of coronation trees which were planted to mark the coronation of the queen in 1963.

To the left of the beech is a small carpark and, just to the left of this, a track which leads you down the side and brings you back out opposite the monument at the start of your walk.