BRUE VALLEY 2014 BIG BAT SURVEY

Transcription

1 BRUE VALLEY 2014 BIG BAT SURVEY 1

2 Summary Nine transects were surveyed in the 2014 Brue Valley Big Bat Survey and nine species of bats were recorded and two other genera. It is quite likely that a total of 13 species were present. Even though only nine transects were surveyed compared with 16 in 2013 the total number of bat passes was only fewer by 134 passes, a reduction of 4.5%. The greatest number of bat passes were from Soprano Pipistrelle comprising 49.8% of all bat passes recorded. The Common Pipistrelle bat was up in 2014 at 30.9% of passes and with a greatly expanded range. The percentage of passes ascribed to the group of Myotis species was down from 17.5% to 13.7%. Both the Greater Horseshoe Bat and Lesser Horseshoe Bat were recorded and roosts are known in this area. The number of Serotine Bat passes was comparable but there were only three Noctule Bat passes compared with 97 in It is worth noting, however, that 79 of those 97 in 2013 passes were recorded at one point in Transect 15, a transect that was not surveyed in Three new species were recorded in 2014 and all are rare. A Barbastelle Bat was heard on Catcott Heath far away from expected roosts and favoured foraging habitat. Leislers Bats were recorded at North Wooton, Meare and Tealham Moor. The third new record was Nathusius Pipistrelle at both Yeaps Bridge and Ham Wall. Further investigation is warranted. Acknowledgements Somerset Bat Group (SBG) ran the second Brue Valley Big Bat Survey for the Brue Valley Living Landscapes and Avalon Marshes Landscape Partnership. The survey depended on the enthusiasm and expertise of local volunteers devoting their time to walking transects, mapping and describing the results and spending hours analysing the sound recordings. This has given an opportunity to build on the findings of the 2013 survey and provide more data of a kind that could not be recorded in any other way. The transects were the same as in 2013 and were designed by Cath Shellswell, Dave Cottle and the late Lou Pickersgill. Those that were surveyed in 2014 were walked in the reverse direction to try and correct any variation in bat activity linked to the animals time of emergence or the distance from their roosts. The administration and organisation of the survey was largely by Cath Shellswell and Adel Avery of SBG with Liz Francis of Somerset Wildlife Trust (SWT). The essential task of manning HQ on the night was undertaken by Kevin Anderson of SWT. The sound analysis was carried out by the Edward Wells and Cath Shellswell and the maps and tables in this report by Laura Quinlan and Cath Shellswell. Special thanks to; The recorders: Paul Kennedy, Pete Banfield, Dave Cottle, Helen Wells, Cath Shellswell, Sarah Ayling, Hannah Montag, Tony Serjeant and Liz Biron. All the volunteers that took part in the surveys: Mark Anderson, Peter Anderson, Sarah Ayling, Colin Banfield, Pete Banfield, Liz Biron, Jenny Clare, Stephen Clare, Dave Cottle, Julie Day, Celia Dillow, Rob Dillow, Kevin Doble, Carole Howe, Paul Kennedy, Chris Lampshire, Tamara Lumb, Hannah Montag, Brian Pounde, Chris Pounde, Reg Redmore, Tony Serjeant, Cath Shellswell, Paul Smith, Rose Teixeira, Edward Wells, Helen Wells, Billie Wilson, Beth Woodburn, Andrea Yates and Martin Yates. All the land holders that allowed the survey to take place around their holdings. All of the people that gave comments on the text of this report. Cover photograph: Leislers Bat (Nyctalus leislerii) Paul Kennedy Report Authors: Edward Wells and Cath Shellswell of Somerset Bat Group and Laura Quinlan. 2

3 1. INTRODUCTION The Somerset Big Bat Surveys were first conceived for the Mendip Hills Living Landscape Team of Somerset Wildlife Trust (SWT) and ran from 2007 and A second survey for the Blackdown Hills AONB Partnership has been run between 2011 and 2014 with plans to continue for a further two years providing funding for supporting the organisation of the survey can be secured. The Big Bat Surveys have received national attention and acclaim following presentations at various conferences. The popularity of these surveys with the public does not seem to diminish with anything from 30 to over 70 people involved on the survey nights. The number for the Blackdown Hills survey has been constant at about 70 people for each of its four years to date. However, for various reasons, the number of people signing up to the 2014 Brue Valley Survey was unexpectedly low and this meant that only 9 out of a possible 17 transects were surveyed. If the surveys continue, support should return to its former level of 60 or more volunteers with greater advertisement and better coordination. The Brue Valley was chosen as the focus following the Mendip Hills survey had run its 6 year course as it is an SWT Living Landscape area and also because it is very different from both the Mendip Hills and the Blackdown Hills. Those are regions of un-intensively managed pasture and woodland with relatively little standing water. The moors and levels of the Brue Valley are lowlying very wet pasture dominated landscapes, at and even below sea level. Except for the conservation managed swathe of the Avalon Marshes there is little woodland. The fields are stocked with cattle and much of the grassland has been agriculturally improved and is much lusher and less species rich than on the shallow limestone of the Mendips or the leached uplands of the Blackdown Hills. In 2013 it became clear that whereas in the Blackdown Hills, Common Pipistrelles (Pipistrellus pipistrellus) were very much more recorded than any other species in the Brue Valley the dominant species was the Soprano Pipistrelle (P. pygmaeus), a bat believed to be more often associated with open water. It was anticipated that the 2014 surveys might add more credence to that finding. As in previous surveys the main purpose was to obtain data by using a repeatable methodology and specifically to obtain flight records that could inform and improve our understanding of how bats use the landscape. Most flight records are by their nature anecdotal and often hard to verify or interpret. By recording the bat passes both on a form and on a recording device it was possible to collect evidence of activity that was capable of being analysed objectively. Some roosts on or near transects are known and it may be possible to relate some of the activity to those populations but there are a great many more bats whose day roosts are not known at all and the data collected in this survey may help us to know where we should be looking. There are 17 species of bat known to breed in Britain and 16 of them are known to be breeding in Somerset. Some of the data from other surveys has been used successfully to support and direct agrienvironment schemes enhancing conservation and providing a source of funding for land owners. In the new agri-environment scheme, Countryside Stewardship, launched in January 2015 Horseshoe Bats (Rhinolophus sp.) are target species for management options and increase the likelihood of land managers with these bats to enter the scheme if they are willing to do management options beneficial for these species. This would have a knock-on effect for other bat species associated with wet landscapes such as Daubenton s Bat (Myotis daubentonii) and Soprano Pipistrelle. Those who own and manage the land traversed can learn and profit from the findings of such surveys. Bats are highly mobile, opportunistic feeders and the presence of bats is in itself an indication of the insect abundance and diversity of an area. The National Bat Monitoring Programme is now regarded as part of National Statistics along with data gathered on farmland birds, and although the Big Bat Surveys are not combined with this data, it does emphasise the importance of bats regarding their place in the ecosystem and as an ecosystem service. By repeating such surveys it may be possible to identify changes for year to year and that in itself may give early warning of a less favourable condition of the land from a wildlife perspective. The other reason for such a survey is to give non-expert local people a chance to help do something positive but very different for their local wildlife and to give them an experience of the wild world which is not usually available to them. The huge popularity of the Big Bat Surveys and of the bat walks that SBG has run for some years with Natural England at Shapwick Heath are an indication of how special the experience is for people. There is a magic in glimpsing the world of the creatures of the night and even hardened bat workers can still feel a thrill at hearing a species they did not expect. It was always envisaged that each survey would be run for 6 years, subject to the necessary funding and man hours being available. However, SWT feel that they can no longer support the Brue Valley survey as they do not feel that bats are a priority in the Brue Valley. The Somerset Bat Group does not agree with this opinion in light of the importance of bats as an ecosystem service as well as the changed in management that can be brought about by understanding bat distribution in the south-west of England, particularly Horseshoe Bats. The Group is actively seeking alternative funders to help bridge the small amount needed to 3

4 pay for coordination of the event. Two years of data for nine transects and one year for a further seven is simply not enough to give any robust assessment of bat activity and landscape use in this nationally important area. 2. METHOD The 2014 Brue Big Bat Survey is a landscape survey to collect comparable data across an area of the Somerset Levels: (a) 17 predetermined routes (figure 1) were mapped and planned for surveying prior to the 2013 survey. They are designed to be walked simultaneously and comprise a series of 6 walking sections and 6 stationary points. Each team of volunteers listens to bats using heterodyne, time expansion or frequency division bat detectors and lists what they heard in each section (b) At the same time one person in each group undertakes a continuous recording on a wave recorder using a frequency division Batbox Duet Bat Detector. The recordings are assigned to separate tracks for each section and then analysed to count the number of bat passes in each section and, so far as possible, assign those passes to species. 2.1 Survey Nine transects were surveyed in All were completed. The Duet recordings for one transect could not be analysed but a simultaneous recording using an EM3 detector was analysed and the resulting data is shown below. Each walk consisted of six stops of 5 minutes and six walked sections lasting an average of about 10 minutes. The stops were chosen strategically where there were potentially significant landscape features and the walks were mainly along established footpaths for the comfort and safety of the volunteers. All landowners along each transect were asked for permission to access their land. The volunteers were provided with maps of the transect they were undertaking, a risk assessment and asked to walk the route in daylight for safety prior to the survey. Further information that was provided to volunteers is available from the Somerset Wildlife Trust. Before starting the surveys, the volunteers met for a brief health and safety talk and then travelled to the beginning of each transect. Four to six individuals with a mixture of bat experience from beginner to very experienced were assigned to each group. One person in each group recorded the route continuously using a Batbox Duet and a wave recorder. The surveys started at 20:45 and finished at approximately 22:15. A chosen volunteer in each group travelled back to the Lifelong Learning Centre at the Avalon marshes Centre to hand-in the recordings and survey forms. 2.2 Sound Analysis Each transects recordings were analysed using BatSound software. The number of bat passes made by each species or group was counted to provide a measure of bat activity along each walk section and stop section. A bat pass is a continuous stream of echolocation calls indicating a bat flying past. A sequence of calls interrupted by a feeding buzz (a rapid accelerating set of calls indicating the capture or attempted capture of prey) was treated as two passes. The number of bat passes is therefore best understood as an index of bat activity rather than the absolute number of bats in the area. Except for the bats of the genus Myotis, each species has a spectrogram which is usually distinctive. 2.3 Limitations of the Survey There are several factors that may affect the results and comparison between the routes: Differences in the range of individual bat detectors individual detectors of the same type can vary in range depending on factors such as local environmental conditions and battery strength. Changes in environmental conditions such as weather can be compensated by carrying out the surveys at the same time on the same night, and new batteries can be used. Observer error misidentifying bat passes and counting the number of bat passes The standard procedure for counting bat passes was followed; however there is scope for error if more than one bat of the same species / genus is passing the bat detector at one time. There is also the potential to misidentify species, particularly if the call is faint. Equipment failure No calls were recorded from the Duet recorder on route 7 Westhay Moor and we show below both the passes registered on the written notes and recordings from an EM3 recorder. There were also cases of passes heard by the surveyors that were not recorded due to the need to replace batteries and in that situation we have relied on the written notes. There is a lower level of confidence in 4

5 the identification of the species missed in this way but given the experience of the recorders concerned we considered it appropriate to accept their identification even though it could not be subjected to objective verification by sound analysis. There is a greater danger of inaccuracies in identifying species from bat passes from heterodyne recordings, and individual bat passes are more difficult to distinguish if more than one bat is flying past the bat detector at the same time resulting in counting errors. The sensitivity of different bat detectors varies and the EM3 recordings may not be directly comparable. Faint recordings - occasionally the echolocation on the recording was too faint to identify the bat species. Faint recordings also make it difficult to extract a peak frequency for the echolocation calls of pipistrelle species. Where the genus of bat was uncertain the recording is marked in the report as bat species and where there is sufficient confidence to assign a recording to the genus Pipistrellus but not to a species the recording is marked as pipistrelle species. Figure 1: Map of the bat transects undertaken as part of the Brue Big Bat Survey 3. RESULTS AND SOUND ANALYSIS 3.1 Overall summary In total, nine species of bats were recorded and two other genera. The calls of the echolocation of the two Long-eared Bat species (Plecotus sp.) are indistinguishable and the similarity in the call structure of the six Myotis species meant that those calls were not differentiated. It is quite likely that a total of 13 species were present. Even though only nine transects were surveyed compared with 16 in 2013 the total number of bat passes was only fewer by 134 passes, a reduction of 4.5%. The temperatures in 2014 may have been slightly higher but were within the same range as the temperatures in Both nights were clear of cloud, dry and calm. It is difficult to see why there should have been more bat activity in 2014 and more data are needed to find out whether this is a feature of the direction in which the transects were walked or a variation caused by the nature of a series of chance encounters. The greatest number of bat passes were again from Soprano Pipistrelle (peak frequency at 55 khz) comprising 49.8% of all bat passes recorded. This appears to confirm the belief that the Brue Levels and Moors are a stronghold for this species which is particularly associated with water bodies and channels. The 5

6 Common Pipistrelle bat, the commonest species throughout Western Europe, was up in 2014 at 30.9% of passes and with a greatly expanded range. The percentage of passes ascribed to the group of Myotis species was down from 17.4% to 13.7% but it is unlikely that that change is significant. If it were to be continued over the next two years there may be reason for concern. It is probable that the majority of Myotis recordings were of Daubenton s Bat, another species closely associated with water but Natterers Bat (Myotis nattererii) is regularly found in bat boxes at Catcott Heath and a Whiskered Bat (Myotis mystacinus) has been caught at Shapwick Heath using a harp trap. Both the Greater Horseshoe Bat (Rhinolophus ferrumequinum) and Lesser Horseshoe Bat (R. hipposideros) were recorded and roosts are known in this area. The number of Serotine Bat passes (Eptesicus serotinus) was comparable but there were only 3 Noctule Bat (Nyctalus noctula) passes compared with 97 in It is worth noting, however, that 79 of those 97 in 2013 passes were recorded at one point in Transect 15, a transect that was not surveyed in Three new species were recorded in 2014 and all are rare. A Barbastelle Bat (Barbastelle barbastellus) was heard on Catcott Heath. Leislers Bats (Nyctalus leislerii) were recorded at North Wooton, Meare and Tealham Moor. This species has only recently been confirmed as a Somerset species and its appearance in widely separated parts of the valley is very encouraging. The third new record was Nathusius Pipistrelle (Pipistrellus nathusii) at both Yeaps Bridge and Ham Wall. This is a migratory species and it is possible that these were bats in transit but Nathusius Pipistrelles are believed to breed in North Somerset and are recorded throughout the summer near Axbridge. Their presence on the Levels is significant and would merit further investigation. Table 1 shows the number of bat passes and proportion of total calls for all the species recorded and the following maps show the presence of species recorded across the survey area. The results only show presence of bats identified from the recordings and cannot indicate the absence of a particular species as the survey does not cover the entirety of each square kilometre, and, consequently, there is the possibility that species may have been missed. Table 1: Number and proportion of bat passes recorded for each species / group. Species / Species Group 2013 Bat Passes 2013 Total (%) 2014 Bat Passes 2014 Total (%) Greater Horseshoe Lesser Horseshoe Common 45 Pipistrelle Soprano 55 Pipistrelle Pipistrelle sp Serotine Noctule Leisler's Myotis sp Long-eared bat sp Barbastelle Nathusuis' Pipistrelle Unidentified bat species TOTAL Bat passes recorded along each transect route The recordings from each transect were analysed separately and divided into the walk and stop sections shown in the following tables and maps. It is, of course, impossible to draw any conclusions from one set of data and the following observations must be treated with caution and can at best merely highlight possible areas of comparison for following surveys. 6

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13 3.2.1 Transect 1: Gold Corner Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 This route was not surveyed in This route was not surveyed in Transect 2: Burtle Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Lesser Horseshoe 1 1 Common Pipistrelle Soprano Pipistrelle Pipistrelle sp 1 1 Myotis sp Serotine Noctule 1 1 Unidentified bat passes This route was not surveyed in

14 3.2.1 Transect 3: Tealham Moor Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Common Pipistrelle Soprano Pipistrelle Myotis sp 1 1 Serotine Long-eared bat Unidentified bat passes * Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Leisler's 1 1 Unidentified bat passes 1 1 * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. Whilst the total number of passes recorded was comparable to that of 2013, in 2014 the number of Common Pipistrelle passes increased by nearly three times. It is difficult to theorise why, particularly as the calls were spread more evenly across the transect. In 2013 there were 4 stages without a single pass and in 2014 only one. The higher number of Myotis passes is something to watch out for in future surveys to try to work out whether there is an increase or simply natural fluctuations in activity. The recordings of Leislers Bats at two different stages are encouraging. 14

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16 3.2.1 Transect 4: Cattcot Heath Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Greater Horseshoe 1 1 Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Long-eared bat 2 2 Unidentified bat passes * Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Barbastelle 1 1 Long-eared bat Unidentified bat passes * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. It is noticeable that most of the intense activity is in the last part of the survey (Walk 3 to Walk 1 inclusive). Does that mean that the bats are coming some distance to feed here and in the normal direction in 2013 the surveyors had moved on before the bats arrived? Another two years data might confirm that. In 2013 it was slightly surprising that Common Pipistrelle passes exceeded those of Soprano Pipistrelles but the normal order for the wetlands was re-established in What was not expected was that Myotis passes exceed both Pipistrelles. The reason was an outstanding result at Stop 2. Was that a good number of bats or a few being very active? This transect is one of the better ones for Serotines. The Barbastelle pass is a new species for the survey and we do not know where it comes from as the species tends to like foraging in woodland with a good understory of shrubs. Although the nature reserve area does provide the habitat the Barbastelle would have needed to have travelled to the reserve unless it roosts in the woodland. Further investigation is warranted. 16

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18 3.2.1 Transect 5: Shapwick Heath Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Greater Horseshoe 1 1 Lesser Horseshoe 3 3 Common Pipistrelle Soprano Pipistrelle Pipistrelle sp Myotis sp Unidentified bat passes * Greater Horseshoe 3 3 Lesser Horseshoe Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Unidentified bat passes * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. The number of Soprano Pipistrelle passes was only a third of the 2013 total but there was still plenty of activity. Serotine was recorded for the first time. The presence of Greater Horseshoe Bats at Stop 1 was unexpected as the known roost is near to Walk 6 but they are large bats capably of going a long way from the roost. Lesser Horseshoe Bats were recorded at three widely separated stages suggesting that they are spreading out over the area. It is known that some of the Lesser Horseshoe Bats that used to share their roost with Greater Horseshoe Bats have moved to a roost on the Eastern side of the road and they may have changed where they feed at the same time. 18

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20 3.2.1 Transect 6: Westhay Village Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Common Pipistrelle Soprano Pipistrelle Pipistrelle sp 4 4 Myotis sp Serotine Unidentified bat passes This route was not surveyed in

21 3.2.1 Transect 7: Westhay Moor Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Common Pipistrelle Soprano Pipistrelle Pipistrelle sp Myotis sp Serotine Unidentified bat passes * Lesser Horseshoe Common Pipistrelle Soprano Pipistrelle Pipistrelle sp Myotis sp Serotine Noctule 1 1 * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. The recording failed on this transect and we show the results recorded subjectively on an EM3 bat detector by Tamara Lumb. We are grateful to her for making those recordings available to us. What is clear is that there was a huge amount of bat activity in the last section from Walk 3 to Walk 1. Both the EM3 recordings and the form showing subjective data from heterodyne detectors show remarkably little Pipistrelle activity at Stop 4 to Stop 3. This is unlikely to be a lack of food in view of the 18 Myotis passes at Walk 4. There is no direct evidence that these species seek to exclude each other when feeding. The contrast in Myotis passes between 2013 (6 passes) and 2014 (91 passes) is considerable and we need more years to show which figure is more typical. The same can be said of total passes which were up from 146 to 818. May this be partly an effect of using two different bat detectors with different levels of sensitivity? 21

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23 3.2.1 Transect 8: Meare Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine 5 5 Noctule 3 3 Unidentified bat passes * Lesser Horseshoe Common Pipistrelle Soprano Pipistrelle Pipistrelle sp 1 1 Myotis sp Serotine Noctule 1 1 Leisler's 1 1 Unidentified bat passes 3 3 * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. Without any issues of the use of different equipment, the number of passes recorded on this transect was substantially higher in 2014 compared with Soprano Pipistrelle passes went up from 19 to a respectable 92 and Common Pipistrelle passes from 24 to 69. The number of Myotis passes fell dramatically. This pattern for both Transect 7 and Transect 8 might suggest that there is some mutual exclusion with Pipistrelles reluctant to feed with Myotis bats or vice versa. There is, of course, too little data to say. The presence of Leislers Bat is important as this species is sparsely recorded across England. 23

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25 3.2.1 Transect 9: Ham Wall and Walton Heath Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Greater Horseshoe 1 1 Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine 1 1 Noctule Unidentified bat passes * Common Pipistrelle Soprano Pipistrelle Myotis sp Nathusius pipistrelle Unidentified bat passes * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. There was an increase of passes by all three of the commonest groups, Common Pipistrelle, Soprano Pipistrelle and Myotis. The activity was also spread throughout the route particularly for Soprano Pipistrelles. In 2013 the Soprano Pipistrelle activity was concentrated in the second half of the transect. Possibly the roost is closer to Stop 6. There was no Greater Horseshoe Bat this year but 6 passes from Nathusius Pipistrelles is a major discovery. All those passes were towards the end of the walk suggesting that it may have taken the bats some time to get there. It will be interesting to see if they appear starting at Walk 1 in a normal year. 25

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27 3.2.1 Transect 10: Yeaps Bridge Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Common Pipistrelle Soprano Pipistrelle Pipistrelle sp Myotis sp Serotine Noctule 1 1 Unidentified bat passes * Lesser Horseshoe 1 1 Common Pipistrelle Soprano Pipistrelle Pipistrelle sp Myotis sp Serotine Nathusius pipistrelle 2 2 Unidentified bat passes * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. There was a Nathusius Pipistrelle here as well and no less important a record. Bat activity was much greater across most species than in 2013 even though climatic conditions were very similar. There were nearly twice as many Common Pipistrelle passes and a 70% increase in those of Soprano Pipistrelles. The increase in Serotine passes is encouraging given a patchy distribution of passes of this species across the survey as a whole. 27

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29 3.2.1 Transect 11: East Backwear Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Greater Horseshoe 1 1 Lesser Horseshoe 2 2 Common Pipistrelle Soprano Pipistrelle Pipistrelle sp Myotis sp Serotine Noctule 1 1 Unidentified bat passes This route was not surveyed in Transect 12: Fenny Castle Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Noctule 1 1 Unidentified bat passes This route was not surveyed in

30 3.2.1 Transect 13: Long and Short Drove Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Pipistrelle sp Myotis sp 5 5 Unidentified bat passes This route was not surveyed in Transect 14: West North Wooton Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Lesser Horseshoe Soprano Pipistrelle Pipistrelle sp 2 2 Myotis sp Serotine Noctule * Common Pipistrelle Soprano Pipistrelle Pipistrelle sp 6 6 Myotis sp Serotine Noctule 1 1 Leisler's 1 1 * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. Another walk on which Leislers Bat was recorded. Have they arrived in the Brue Valley since last year or did we fail to spot them in 2013? It is a species that was unrecorded for many years in Somerset although there were a number of records of possible Leislers over the last 7 years, some on the low-lying parts of the Parrett valley. Myotis bat passes were still the dominant feature as in 2013 but the total numbers were much lower. There do not appear to be many Pipistrelles here and it is quite likely that there is a Myotis roost somewhere near Stop 2 and Walk 2. 30

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32 3.2.1 Transect 15: Hulk Moor Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Lesser Horseshoe 1 1 Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Noctule Unidentified bat passes This route was not surveyed in Transect 16: South Moor Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 This route was not surveyed in This route was not surveyed in

33 3.2.1 Transect 17: Church Moor Year Bat species Transect section Walk 1 Stop 1 Walk 2 Stop 2 Walk 3 Stop 3 Walk 4 Stop 4 Walk 5 Stop 5 Walk 6 Stop 6 Total 2013 Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Unidentified bat passes * Common Pipistrelle Soprano Pipistrelle Myotis sp Serotine Unidentified bat passes 1 1 * The 2014 survey was completed in reverse starting at Stop 6 and finishing at Walk 1. There is a slight reduction in Soprano Pipistrelle activity but a very large increase in that of Common Pipistrelles. The passes from the latter species out-numbered its cousin by more than two times. Why should this be so? A part of the transect is along the river bank but otherwise this is one of the drier areas surveyed so a larger number of Common Pipistrelle passes is not unexpected. That does not explain why the two years are so different. The increase in Myotis passes is attributable to the activity at Stop 5. 33

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