The Elekon Batlogger M2 is a sophisticated bat detector, designed for use in active transect surveys and bat walks. The detector is ergonomically designed and compact in its build. Unlike the Batlogger M, the replaceable microphone is set back within the casing, reducing the chance of breakages if accidentally dropped.
It is an easy-to-use detector, able to record ultrasonic calls over a wide range of 10-192Hz, retaining details of the harmonic structure and amplitude of the original bat call.
This detector also includes features for real-time heterodyne monitoring scheduled recording and several preset recording modes for typical survey types, including ‘Explore’, ‘Transect’ and ‘Passive’. There is also an option to create your own presets, with all settings accessible directly on the Batlogger M2.
The recordings can be easily and quickly managed and analysed using the free BatExplorer Software for Windows. This software also includes computer-aided species identification.
How we tested
In August 2021, we tested the Batlogger M2 on Dartmoor in South Devon at dusk. We chose an area with both open moorland and woodland to monitor the dusk emergence of several bat species. Using the ‘Explore’ recording mode, the device was set to real-time heterodyne monitoring, with the trigger settings selected to 45Hz.
The recordings were stored on a 16GB MicroSD card, output via WAV and XML. The files can be easily transferred to your computer with the included cables (a USB-C to USB-C cable and a USB-C to USB-A adapter) however, we simply used an SD card reader to access and transfer our recordings.
Elekon’s ‘BatExplorer Lite’ software was used to visualise and analyse our recordings.
What we found
At only 222g, this device is lightweight, therefore it was not a hindrance when hiking to the site. It was easy to hold and operate in low light, which is important as it will often be used in conjunction with other equipment while undertaking surveys. However, the buttons do not light up or glow in the dark, therefore it is important to familiarise yourself with the setup beforehand.
Our survey used the ‘Explore’ recording mode however, we looked briefly at the other preset modes and felt they would be very useful if carrying out these types of surveys. In particular, the ‘Transect’ mode allows you to pre-program the detector with your own GPS survey route, which will then display directions to keep you on path.
Setting up our recording session was quick and easy. When triggered, the detector automatically recorded the calls in full-spectrum, therefore no further operation was required. Each recording logs the GPS location, temperature, humidity and brightness at the time of recording, so there is no need to bring separate equipment for these parameters. The device also has an integrated voice microphone to enable you to take time-stamped voice notes while surveying, which allows for more accurate note-taking than writing in the dark.
The screen display was bright and easy to view in the dark. The main screen shows the current recording time and frequency, as well as amplitude and harmonic structure of the previous bat call, the time since the last sequence and the species suggestion for that recording. The other recorded information can be accessed by pressing the left and right buttons to switch screen displays, allowing for an uncluttered screen and fewer distractions.
We tested the detector’s audio output with both earphones and through the built-in speakers (includes an adjustable volume). Both had clear audio with little background noise.
We recorded multiple calls including over 60 calls during one 30 minute survey. We were impressed with the quality of the recordings and the lack of ambient noise assisted in the identification of calls. It is worth noting that the M2 uses a SiSonic microphone, whereas the older Batlogger M uses an FG Knowles microphone, so experienced Batlogger M users may notice a slight difference in their recordings.
Automatic species identification was not always to species level, with some recordings having no suggested species. Those that were suggested, however, appeared mostly accurate when we analysed the recordings via the BatExplorer software.
Our opinion
The Batlogger M2 by Elekon is a very easy-to-use and accessible detector. The preset recording modes are useful for almost all circumstances and allow quick survey set up without the need to trawl through complicated settings – particularly helpful for newer ecologists. The only limitation we found was the lack of visual aids for the buttons in the dark, however, this can be easily overcome by familiarisation and repeated use.
It is clear from the design of the M2 that Elekon has acted on feedback from the Batlogger M and have created an intuitive detector with a robust build, perfect for any survey needs.
The Elekon Batlogger M2 can be found here. Our full range of active bat detectors can be found here.
If you have any questions about our range or would like some advice on the right product for you then please contact us via email at customer.services@nhbs.com or phone on 01803 865913.
Rabbits and hares are species in the family Leporidae, which contains over 60 species. They are mammals within the order Lagomorpha, together with the pikas. They are small to moderate-sized species, characterised by long hind legs, long ears and rapid movements. They are almost exclusively herbivorous, feeding mainly on grasses and herbs, although they do also eat leaves, fruits and seeds. Leporids are coprophagous, meaning they pass food through their digestive system twice. To do this, they first expel the food as soft green faeces, termed cecotropes, which they then reingest, eventually expelling it again as dark faecal pellets. This increases their ability to break down and digest plant material, extracting further nutrients.
They inhabit a wide range of habitats, from mountains and wetlands to forests and grasslands. Leporids play an essential role in many of these ecosystems, as seed dispersers, ecosystem engineers (a species that significantly modifies their environment) and as a primary prey item for a number of predator species, such as foxes, wildcats and some mustelids, including stoats and weasels. Their young are particularly vulnerable to these predators, as well as badgers, domestic cats and several birds of prey. Because of this vulnerability, many leporids have large litters, often nesting in burrows underground to protect their young from predation.
One threat to populations, particularly in European rabbits, is myxomatosis, a disease caused by the poxvirus Myxoma virus. Its two natural hosts, the tapeti and brush rabbits of South, Central and North America, experience only mild disease. However, myxomatosis is a severe and usually fatal disease in European rabbits. When the disease originally spread to the UK in the early 1950s, the mortality rate was 99%. In the 1970s this declined to between 47 and 69% but populations were severely affected. The disease, which causes localised swelling, skin lesions, blindness and respiratory distress, has also been deliberately introduced into the wild on multiple occasions. Used to try to eradicate or control rabbit pest populations, myxomatosis was intentionally introduced in Australia, New Zealand, South America and parts of Europe, including Britain.
Other threats to leporid populations include rabbit haemorrhagic disease (RHDV1 and RHDV2), hunting, habitat loss and agricultural intensification. Rabbit populations declined by 64% in the UK between 1996 and 2018 and numbers of brown, mountain and Irish hares are also thought to have declined in some areas. As ecosystem engineers, the loss or reduction of these species can have major consequences, particularly for rabbit-dependent habitats. In their absence, the consequent changes in vegetation structure due to a lack of grazing can have further impacts on other wildlife, such as invertebrates.
Rabbit (Oryctolagus cuniculus)
Distribution: Widespread across the UK, although they are absent from Rum, Isles of Scilly and some smaller islands. What to look for: Rabbits are the smallest leporids in the UK, with the characteristic long ears and long hind legs. They have a sandy, grey-brown colouration and a white tail. They have dark, amber coloured eyes. Other than their size, the most noticeable difference between rabbits and other leporids in the UK is the lack of a black tip on the ears. Did you know? The rabbit, also known as a coney, is not native to the UK. The exact date of their introduction is one of ongoing research. It was previously thought that rabbits were first introduced by the Normans in the 11th or 12th century as both a food and fur resource. But the recent re-examination and radiocarbon dating of a bone found at a Roman palace show that at least one rabbit was present much earlier, in the first century AD. Researchers have stated that there is no evidence of many rabbits in the area and another analysis suggests the rabbit was kept in confinement, therefore it has been suggested that it was most likely kept as an exotic pet.
Distribution: Widespread across the UK, although they are less common and more restricted in Northern Ireland and absent from parts of north-west Scotland. What to look for: This species is larger than the rabbit, with long, black-tipped ears and very long hind legs. Their colouration is redder than the rabbit and the mountain hare, and they have a black-topped tail that is white underneath. The brown hare has amber eyes and their fur can appear grizzled. Did you know? This species is also non-native and were introduced in the Iron Age. Radiocarbon dating of bones found in Hampshire and Hertfordshire, along with historical accounts, suggest that brown hare were not eaten until hundreds of years later during the Roman period, and were instead associated with deities.
Distribution: Mainly in the highlands of Scotland, although they are also found in other areas of Scotland, on some Scottish islands and in the Peak District. What to look for: This species has a grey-brown coat during the summer and a white coat in the winter, although the tips of their ears remain black in both forms and their tail remains white. They have brown eyes and long ears, although these are shorter than the brown hare’s.
Brown form: Andrew via FlickrWhite form: John Johnston via Flickr
Irish hare (Lepus timidus hibernicus)
Distribution: Widespread across Ireland What to look for: They are very visually similar to the mountain hare, except they do not develop a white coat during winter months and are noticeably smaller. During the summer, their coat is reddish-brown which dulls to grey-brown in winter, although their tail remains pure white. Did you know? The Irish hare is a subspecies of the mountain hare and is the only lagomorph species native to Ireland. Fossil carbon dating suggests that these hares have been present in Ireland for at least 30,000 years.
Distribution: Unknown What to look for: Domestic rabbits can have a huge variety of appearances, with at least 305 breeds of domestic rabbits around the world, although different numbers are accepted by different organisations. They can vary in size, colouration, body shape, coat type and ear length. Did you know? Many pet rabbits are abandoned each year, particularly in the period after Easter.
This festive season, why not consider giving a gift that will also support your local wildlife. Wildlife populations in the UK are facing serious threats and many species are in decline, however there are ways in which we can protect and help at-risk species by creating havens for wildlife in our own gardens. At NHBS we sell a range of products, from bird feeders to hedgehog houses, that can both bring joy to the recipient and benefit wildlife at the same time. We also sell a number of books that can help you create a wildlife friendly garden. We’ve put together a selection of some of our favourite items for you to browse below.
Hedgehog numbers have dramatically declined in recent years. Creating a hole in a garden wall or fence will allow your local hedgehogs to pass through from garden to garden safely.
Many bird species are struggling to find enough suitable natural nesting sites in the modern environment, but a bird box will provide a warm, sheltered substitute, with protection from most types of predators, helping to improve the chances of breeding success.
The Frogilo Frog and Toad House provides a safe retreat for frogs and toads in any garden and is handmade in frost-resistant ceramic with a decorative glazed roof.
The National Trust Apex Insect House is an ideal addition to any wildlife friendly garden. With a variety of shelter types, it offers a perfect habitat for important invertebrates such as lacewings, ladybirds, and even some butterflies.
Bee Bricks are made in Cornwall in England using the waste material from the Cornish China clay industry. They provide much needed nesting space for solitary bee species such as red mason bees and leafcutter bees, both of which are non-aggressive.
A large and beautifully coloured and glazed bird bath with a ‘ripple’ step design that is both visually attractive and functional by providing extra footing/grip for wild birds.
The Defender Feeder’s metal construction is tough, long lasting and offers excellent protection from squirrel damage. The feeder is available with two, four or six feeding ports, each with a perching ring that allows birds to feed in a natural, forward facing position.
Hedgehog numbers are rapidly declining across the UK and providing a refuge in your garden with the Wildlife World Hedgehog House will help to protect hedgehogs from predators and disturbance.
This is a guide for anyone wanting to garden in a more sustainable, natural way. Working with nature benefits not just the garden, but also the gardener, wildlife and the wider environment.
This shows you how you can provide a refuge for bumblebees to feed, breed and thrive. No matter how large or small your space is, Dave Goulson shows you how you can make a pollinator-friendly haven.
This offers a fresh and unique perspective on ponds, encouraging readers of any budget to reach for the spade and do something positive to benefit their shared neighbourhood nature.
If you want to attract more bees, birds, frogs and hedgehogs into your garden, look no further than this. Kate Bradbury offers tips on feeding your local wildlife and explains how you can create the perfect habitats for species you’d like to welcome into your garden.
Discover more great gift ideas on our website. Plus, check out our two blogs on how to attract wildlife to your garden.
The Bat Conservation Trust’s annual National Bat Conference, held online via Zoom from 29th–31st October, covered many aspects of bat conservation through a wide variety of activities and talks, including monitoring, surveying and development. We are extremely pleased to have sponsored this event and we were lucky enough to have been able to attend many of these sessions, including talks by Professor Tigga Kingston from Texas Tech University on the human dimensions of bat conservation, and Thomas Foxley, University of the West of England, who spoke about the role of landscape features in spatial activity patterns of greater horseshoe bats. We also attended a few of the amazing workshops that took place, such as Shirley Thompson’s gardening for bats.
Bat Conservation Trust update
Bat Conservation Trust also shared an update on their current and future work. Bats make up more than a quarter of all mammal species in the UK, but sadly, these species face many threats. Habitat loss and fragmentation, decreasing food resources, chemical use, disturbance to roosts and threats from cats have all led to a dramatic decline in bat populations over the last century. Diseases, wind farms, flypaper, artificial lighting and the presence and construction of roads also negatively impact.
Lesser horseshoe bat (Rhinolophus hipposideros) bats roosting by Jessicajil via Flickr
Currently, Bat Conservation Trust supports a number of local bat groups, working with volunteers, scientists, industry and government on a range of projects. They focus on discovering more about bats, taking action to protect them, inspiring people to care about bats and strengthening their work by improving relevant skills and knowledge. Their programmes include a National Bat Monitoring Programme, education and engagement, the National Bat Helpline, Landscapes for Bats, and science and research.
During this update, Bat Conservation Trust spoke of the many ways they will be increasing their efforts to help bat populations, for example by increasing the spread of their monitoring programs and organising a petition regarding key amendments to the Environment Bill, including legally binding targets for wildlife recovery. Through new acoustic and monitoring approaches, they also aim to improve their evidence base and Bat Conservation Trust are also working towards improving their engagement with policymakers, the public and the media. Their Bat in Churches project has also been expanded to include training on bat care basics, surveying a church, the best architectural practices for bats and cleaning workshops.
One key scheme they are developing is the Bat Roost Tree Tag Scheme where recognisable tags are placed on trees that contain bat roosts. The aim of this is to make sure all trees that have been surveyed and found to contain bat roosts are easily identifiable. When woodland managers and workers see a tag on a tree, they will know to seek advice before proceeding with work. This will also give a significantly increased level of protection for ancient trees, which are vitally important for a large number of species.
Future events and how to get involved
The National Bat Conference was a very interesting and educational event, and it was wonderful to see such a wide range of knowledge and skillsets being shared through the many talks, activities and workshops throughout the weekend. If you missed out this time or would like to attend further events, the Bat Conservation Trust has a number of future events planned, including Spring into Action, Midlands Bat Conference and the East of England Bat Conference. More information about these and other events can be found on the Bat Conservation Trust website.
There are a number of ways you can help to support Bat Conservation Trust, such as by becoming a member or donating. You can also contact your local bat group, fundraise for bats or volunteer for their various projects. However you choose to get involved, you can make a real difference to the future of bats in the UK.
Mustelids are species in the family Mustelidae of the order Carnivora. They are medium to small mammals comprising around 56-60 species worldwide, eight of which are found in the UK, including feral ferrets. While the conservation status of most is considered Least Concern in Great Britain, several of these species are considered Critically Endangered or Near-Threatened in individual UK countries. This is mainly due to historical and current persecution and habitat loss. Pollution, however, has also impacted mustelid species, such as the otter, which was particularly affected by pesticides, such as organochlorines. Thankfully, many of the most harmful pesticides have been banned in most European countries since 1979, allowing populations to begin to recover. Other conservation efforts, such as legislative protection, habitat restoration and relocations, are also helping to restore mustelid populations.
Mustelids, other than badgers, are characterised by their long, thin body shape, which allows them to enter burrows and tunnels used by their prey. These mainly include rabbits and small mammals, but also some birds, bird eggs, invertebrates and fish. Several species resemble one another, particularly the stoat and the weasel, but several key identification features can help you to correctly identify the species. Colouration, body size and distribution within the UK can be helpful, as well as other features such as tail size, shape and colour, snout shape and even their running gait. Binoculars or a scope can help you to identify these features from a distance.
Polecat (Mustela putorius)
Distribution: Found throughout Wales, parts of Scotland and central and southern England. Body length: 32–45cm Tail length: 12–19cm What to look for: This species has dark brown guard hairs, the top or outer layer of the coat, and buff-coloured underfur, giving them a two-tone appearance. They have a dark face with a white stripe across it, similar to a ferret. They can produce hybrid offspring with ferrets that can be difficult to identify, but the hybrids usually have a lighter appearance and more white on their faces.
Distribution: Mainly found in Scotland and Ireland, although fragmented populations are found in northern England and North Wales. Body length: 46–54cm Tail length: 18–27cm What to look for: The pine marten has a chestnut-brown colouration with a pale yellow patch on its chin and throat that resembles a bib and a long, bushy tail. The ‘bib’ is uniquely shaped on each pine marten, meaning individuals can be identified by the pattern.
Distribution: Widespread throughout the UK, although absent on the Isles of Scilly, most of the Channel Islands and some Scottish islands. Body length: 17–32.5cm Tail length: 6.5–12cm What to look for: This species is orangy-brown with a cream-coloured underside and throat. They have a very similar appearance to the weasel but there are some key differences: the stoat is larger, with a longer, black-tipped tail and a distinctive bounding gait compared to the run of the weasel.
Distribution: Widespread in England, Wales and Scotland but is absent from Ireland and most islands. Body length: 11.4–26cm Tail length: 1.2–8.7cm What to look for: The weasel is the smallest species of Carnivora in the UK, with a russet-brown coat that can appear more orange in certain lights, and a cream underside and throat. Their tails have no black tip and are much shorter compared to the stoat’s tail, and they run with a straight back, rather than the arched, bounding gait of the stoat.
Distribution: Widespread across the UK, thought to be absent from the far north of Scotland and some Scottish Islands. Body length: 31–45cm Tail length: 13–23cm What to look for: The mink has dark brown fur with a white chin and throat and a narrow snout. They can resemble otters but they can be distinguished by their smaller size and face, as well as their darker fur. Did you know? The American mink is an invasive species, introduced into the wild in the 1950s and 1960s as a result of fur farm escapees and deliberate releases. Accurate population estimates are difficult but many areas are attempting to control numbers as American mink are a serious threat to the endangered water vole (Arvicola amphibius).
Distribution: Rare but widespread throughout the country, although absent from areas in central and southern England, the Isles of Scilly, the Isle of Man and the Channel Islands. Body length: 60–80cm Tail length: 32–56cm What to look for: This species has brown fur with a grey tint, a paler chest and throat and a broad snout, which can be used to distinguish it from the mink. Did you know? In the UK, otter populations were in severe decline in the second half of the 20th century, due to hunting, pollution from pesticides and habitat loss. Conservation efforts have allowed populations to start to recover, with otters returning to every county in England.
Distribution: Widespread throughout England, Wales, Scotland and Northern Ireland. Absent from far north Scotland, Scottish Islands, the Isles of Scilly, the Isle of Man and the Channel Islands. Body length: 75–100cm Tail length: 15cm What to look for: This is a distinctive species, with a grey back, black underside and paws, a fluffy, short tail and an unmistakable black-and-white striped face.
Distribution: Feral populations throughout Britain, but thought to survive best on offshore islands, such as Shetland, Mull, Harris, Islay, Rathlin Island and North and South Uist. There is also a population in North Monaghan. Length: 48–56cm (including tail) What to look for: This species has multiple colour variations, including white, brown, black or mixed fur. Their nose is usually pink, although they can have darker blotches, and they have a thin white band across the face with darker eyes, giving it a bandit-like appearance. They can be hard to distinguish from the polecat, from which it is descended. Where there is an established population of both species, hybridisation can occur. Patches of white on the fur, particularly the paws, can indicate either a ferret or a hybrid.
Bats are elusive creatures; they are nocturnal, and so you are less likely to spot them compared to other UK wildlife, despite bats making up almost a quarter of our native mammal species within the UK. Some species have experienced severe declines, although current trends indicate that a few of these are now recovering. There is still much to learn about bats, however, and ongoing monitoring plays an important role in improving our knowledge of bat population trends.
Where to find them?
Bats are more likely to be found roosting in natural crevices, as opposed to building nests like birds or other small mammals. They can roost in trees, roofs, or outdoor cavities in buildings such as houses, as well as other natural or manmade structures, such as caves and bridges. As they hibernate during the winter, bats are the most active between April and November, and the best time of day to watch them is at dusk. They’re found in many habitats, particularly woodlands, farmland and urban areas (such as gardens).
Identifying Bats:
There are 17 species of bats that have breeding populations in the UK. They are commonly identified by their calls, as the rhythm, frequency range and repetition rate varies between species. A bat detector can be used to easily identify individual bat species in the field; you can browse our range here. In this article, however, we will be looking specifically at the physical characteristics that aid in the identification of 11 of our more common bat species.
Their size, colouration, nose shape, and the size and shape of their ears are helpful features to look at when identifying them by sight. More complicated identification features include the presence and size of the post calcarial lobe, a lobe of skin on the tail membrane, and the length of the forearm.
Pipistrelles
The most common species, and the ones you’re most likely to see, are pipistrelles. There are three species, the common pipistrelle (Pipistrellus pipistrellus), the soprano pipistrelle (P. pygmaeus), and the Nathusius’ (P. nathusii), with the first two being the most common and widespread of all UK bat species.
Common pipistrelle by J P via FlickrSoprano pipistrelle by I. Watson Loyd
ID notes: All three species look very similar, with dark brown fur, a paler underside, and a darker mask-like pattern around the face. Nathusius’s pipistrelles are rarer, and slightly more easy to tell apart due to their lighter underside, larger body size, and furrier tail.
Size: 3.5-4.5cm in length (Nathusius’: 4.6-5.5cm)
Wingspan: 20-23cm (Nathusius’: 22-25cm)
Great and Lesser Horseshoe Bats
Latin names:Rhinolophus ferrumequinum and R. hipposideros
Lesser horseshoe bat by Alexandre Roux via FlickrGreat horseshoe bat by Nils Bouillard via Unsplash
ID notes: Both these species have a fleshy nose shaped like a horseshoe. The lesser horseshoe is much smaller, with greyish-brown fur on its back and a white underside, while the greater horseshoe is larger and has more of a reddish-brown colouration on its back and a cream underside.
Size: Lesser: 3.5-45cm in length, Greater: 5.7-7cm in length
ID notes: The whiskered bat is quite difficult to distinguish as they are visually similar to Brandt’s bats. They have brown or dark grey fur with gold tips, and a lighter grey underside. They have a concave posterior edge to their tragus, the piece of skin of the inner ear in front of the ear canal, whereas Brandt’s bats have a convex posterior edge.
ID notes: This bat has brown fur, a paler underside that appears silvery-grey, and a pink face. This species is most likely seen around water as they forage for small flies above and on the water’s surface.
Size: 4.5-5.5cm
Wingspan: 24-27cm
Brown and Grey Long-eared Bats
Latin name: Plecotus auratus and P. austriacus
Brown long-eared bat by Javier Ábalos via FlickrGrey long-eared bat by Alexandre Roux via Flickr
ID notes: These bats, as their names suggest, have very long, large ears which can be almost the same length as their bodies. These species look very similar, with greyish-brown fur, although the grey long-eared bat has a darker face.
Size: Brown: 3.7-5.2 cm, Grey: 4.1-5.8cm
Wingspan: Brown: 20-30cm, Grey: 25-30cm
Natterer’s Bat
Latin name: Myotis nattereri
Natterer’s bat by I. Watson Loyd
ID notes: The Natterer’s bat has a bare, pink face and light brown and grey fur on its back, with a paler underside. Its ears are quite long, and it has bristles along its tail membrane.
Size: 4-5cm
Wingspan: 24.5-30cm
Bechstein’s Bat
Latin name: Myotis Bechsteinii
Bechstein’s bat by I. Watson Loyd
ID notes: The Bechstein’s bat has long ears which, unlike the barbastelle’s, do not meet at the forehead. Their fur is reddish-brown with a paler, grey underside, and a pink face.
Size: 4.3-5.3cm
Wingspan: 25-30cm
All bat species are European protected species, therefore they and their breeding and resting sites are fully protected by the law. It is important to note that a licence is required for capturing and handling bats, as well as for any activity that may disturb a bat roost, including photography.
Acoustic detection is a popular and widespread method of environmental assessment, and its use is increasing, driven by the development of increasingly accessible and sophisticated detection devices. The Handbook of Acoustic Bat Detection provides an in-depth understanding of the principles of acoustic detection, study planning, data handling, properties of bat calls, analysis of results, and the manual identification of species. It also includes information on quality assurance, the benefits and drawbacks of automatic species recognition, and the background physics of sound.
We are fortunate to have had the opportunity to ask the authors some questions.
The applications of data derived from acoustic bat detection are diverse and wide-ranging. What motivated you to write The Handbook of Acoustic Bat Detection and what impact do you hope the book has in this field?
In our daily work, we have seen a lot of improper use of acoustic data. Mainly driven by misconceptions regarding the interpretation of acoustic data and quite often due to missing basic knowledge on bioacoustics and signal analysis. With the easy availability of acoustic detectors and the relative simple usage, these problems became more common, especially in consulting activities. Many new “bat experts” appeared in the field basing their work on automatic detection and identification systems. We hope to help such users to gain a basic understanding of bioacoustics and give more experienced users new information to further improve their work. Thus overall we hope to improve the quality of projects based on acoustic data and increase the evidence level.
This book discusses some of the different methods for processing acoustic data, such as zero-crossing. What are the benefits of this method versus full-spectrum analysis?
The main benefit of zero-crossing is the much smaller amount of data produced and the possibility of listening to the recorded sounds directly. Full-spectrum detectors produce much larger amounts of data and do not allow direct listening to the bat calls. Yet, the benefits of zero-crossing are decreasing with cheaper data storage and higher processing power. Thus today one can nearly instantaneously listen to full-spectrum sound resampled to zero-crossing or heterodyne representation in real-time. In our opinion, the real-time data gives more insights into the calls on a much easier-to-understand level, yet we accept that experts can do powerful analysis with zero-crossing data as well.
You have all had many years of experience in this field; how has bat detection and acoustic analysis developed and changed since you first started?
We started working on bat acoustics in the field when only heterodyne or zero-crossing detectors were available. So in our early days, we walked through the field listening for bats. We were already interested in better and more reliable species ID back then. Then the time-expansion system was available as well as the Anabat system. We used time-expansion a lot, but both didn’t work well for our scientific research interests. So we developed with the batcorder a real-time detector that completely changed bat work in Germany within a few years. Back in the beginning, sound analysis of bat calls was something only a few were able to do. Now with fully automated systems, the whole process changed. Surveys can run for multiple months nearly everywhere – not only ground-based but also on wind turbines or off-shore. We collect billions of bat calls a year with these systems and thus are able to learn more about their calls and ecology. Yet this is not always the best, since a lack of bat knowledge often prevents optimal solutions for bat-related landscape changes.
Bat acoustic recording visualised through the Anabat Insight Software
In chapter 11, ‘Quality assurance of reports’, you provide criteria to improve the quality of specialist reports used in impact assessments, such as which information should be included and the procedures that should be followed. How do you think the previous lack of clear guidelines has impacted bat surveying and, consequently, conservation?
In Germany, quite often surveys were conducted and it was later not possible to understand the low or high results since important information was missing. Also for legal complaints in planning processes, it was quite often impossible to understand how the data was actually sampled. If surveys and methods are well documented, it is much easier to evaluate the planning process and even more to work out optimal sampling schemes for following surveys in the new planning processes.
Now that this book is complete, do you have any future projects you would like to tell us about?
There are many projects – especially since we now face a major green-green dilemma with climate conservation often acting against biodiversity conservation. This especially is visible in the renewable energy sector. So currently some of us are investigating chances to further identify the possibilities of improving bat conservation for planning wind parks and other sources of renewables.
Another project is the ongoing improvement of species identification based on bat calls. We are working on new solutions to give better results.
Here we review the Anabat Scout from Titley Scientific. The Scout is an easy to use active bat detector that offers excellent quality live audio and recording, plus many handy surveying features and durability that sets it apart from other detectors. It uses heterodyne, auto-heterodyne and frequency division audio that can be recorded in either full spectrum or zero crossing files.
Designed with professional surveyors as well as the more serious bat enthusiast in mind, the Scout is an ideal detector to take on bat emergence and transect surveys. This is thanks to great features such as a bat counter and GPS tracking transect mode.
How we tested
In early July 2021, we tested the Scout outside an old barn in South Devon to monitor the dusk emergence of several bat species. The building was known to host many common pipistrelles, brown long-eared, lesser horseshoes and some myotis species. We wanted to see how easy the detector was to use in the setting of a busy emergence and get a feel for its recording quality and its special features. The audio was set to auto-heterodyne to see how good this feature would be with multiple bats close by. Under the trigger settings is the option to adjust the sensitivity, which we set to high as there was unlikely to be too much undesired noise in this setting.
What we found
Firstly, it is worth noting just how lightweight (at 160 grams without batteries) and easy to hold the Scout is with its handy wrist lanyard and comfortable fit within your hand. These features are particularly important when undertaking long surveys and holding other equipment such as a clipboard for instance.
The OLED display screen is small, but bright, so key information such as peak frequency and time is easy to note in the dark. With just key information visible, the screen does not become too “busy” unlike some detectors, which in some circumstances is a real advantage as it avoids too much distraction. The buttons all glow in the dark, which we found very useful once it had become completely dark, as it kept navigation simple, without having to use a torch.
One of the Scout’s most handy features are the in/out bat counter buttons which enable you to easily tally the number of bats recorded coming out and back into a roost, without the need to look away to make notes and perhaps miss bats. The counter also time and date stamps and geotags each count (CSV file output), so saves you having to manually note this data.
The Scout has a transect mode which notes a GPS coordinate every second so maps out your route as you walk it. It also logs another GPS coordinate for every bat recording made which produces detailed transect maps.
We found that the adjustable volume control was very good and loud enough when needing to compensate for background noises such as a passing lorry.
Also noteworthy was the Scout’s ability to record voice notes. Once it has become fully dark or if you are surveying and need to keep your eyes fixed on bat watching, then the ease of just speaking into the device to add survey notes or further information is very helpful.
The Scout was very productive at picking up all the bats we encountered during the evening (although sometimes a brown long-eared emerged without calling and was missed). The auto-heterodyne tuning to the peak frequency was superb and saved much time. On a few occasions, we switched to manual heterodyne which enables you to adjust the frequency by moving the up and down arrows. This setting would be useful when first teaching beginners. The Scout’s range is also excellent, which was demonstrated when a high flying noctule was picked up probably over 30 – 40 meters away.
Two recordings taken on the Anabat Scout and visualised through the Anabat Insight Software.
The recordings were always clear through the built-in speaker, although there is also the option to attach a 3.5mm headphone jack. All recordings come with GPX track files attached. This gives accurate GPS data, that when viewed on the free software: Anabat Insight, a .KML (Keyhole Markup Language) file can be generated using Google Earth which will show your route with location tags for each bat recording.
All recordings were stored on an SD Card (recommended min: 32GB and max 512GB) and then output via WAV (Full spectrum) and Anabat sequence files (Zero Crossing).
Battery life lasted roughly 10 hours on 2 x AA (NiMh, Alkaline or Lithium) batteries with the remaining memory space and battery life displayed on screen, so we could keep a check during the evening.
Our Opinion
The Anabat Scout is certainly one of the easier to use, professional bat detectors available. It is highly accurate with its triggers and by being so lightweight and practical it makes for an ideal choice for both ecological surveyors and keen naturalists alike. The Scout has been designed with the needs of surveyors in mind and even those new to bat detecting, will find it simple to use and highly rewarding.
The main limitation found was that the Scout does not display full spectrograms like the Anabat Walkabout, therefore beginners particularly, may not find this detector so helpful for learning the differences in calls and identification in the field.
Overall, we feel the Scout offers very good value as an active detector that will fulfill the needs of most ecological surveyors. Its advantage of being incredibly easy to use and get to know, makes it fantastic for beginners, subcontractors and educational purposes also.
The Anabat Scout can be found here. Our full range of active bat detectors can be found here.
If you have any questions about our range or would like some advice on the right product for you then please contact us via email at customer.services@nhbs.com or phone on 01803 865913.
Eva Bishop, Communications Director for Beaver Trust, recently took the time to talk to us about the important work the charity is doing to help communities welcome beavers back to Britain.
In this thought-provoking conversation, we discuss some of Beaver Trust’s upcoming projects, how the Covid pandemic has affected them as a charity, and share different ways to get involved in beaver conservation within Britain.
1. Firstly, can you tell our readers a bit about the Beaver Trust and its main aims?
Our overall mission is to restore Britain’s rivers and wildlife with beavers. We were not in fact established as a single species charity, but as a small crew wanting to build climate resilience for people and wildlife – yet we see the potential for rapid and restorative action that beavers offer. If you take a look at a map of British waterways it depicts an expansive system of veins carrying the lifeblood of the country. Then imagine huge swathes of that being given greater space for nature, becoming living wetlands and water storage systems rather than drained, polluted, straightened ditches. Beavers are our ally here so we are working collaboratively with a range of organisations and of course landowners to support their return.
Beaver Trust’s core work involves convening real conversations in order to make good decisions on national beaver policy and a supporting management framework, finding engaging ways to achieve outreach and education on learning to co-exist with beavers again, and of course supporting many beaver projects on the ground. Our national aim must be to move beyond enclosed projects wherever possible so that beavers can once again become part of native wildlife fauna and work across whole catchments to reinstate biodiversity and healthy ecosystem function.
2. There is a lot of contention between some landowners and conservationists around the subject of beavers, particularly when it comes to reintroductions. Do you find that misinformation and prejudice are significant challenges in the case of this species?
Where misinformation and prejudice exist it’s always unhelpful. However, I think the existence of conflict can be overplayed with beavers and our experience has been one largely of cooperation and collaboration.
Beavers and their impacts aren’t always beneficial to the surrounding land use, we’re very clear about that. Where contention does arise it can often be overcome through better information and knowledge. Well practiced management techniques are being successfully used across Britain, with the right experience and resources there is no reason for these not to become second nature like tree protection against deer for example. Beavers are reestablishing already, but we have an opportunity to target areas for new wild releases that are less likely to cause conflict and instead achieve greater benefits for society and wildlife. That’s something we are collectively all working towards, to minimise conflict.
There is always room for misinformation – hence our core strand of work around communications and education – and there is still work to be done engaging a broad audience in key conversations around beavers (such as farming, angling, flood-banks and the appropriate use of lethal control), ensuring broad diversity in all conversations and that everyone is heard. There is a lot of good research available on the impacts and effects of beaver reintroduction across Europe, not to mention the research within Britain as well. Management is also well-established and now requires government resources to expand nationally alongside training and communications, so that we can offer a swift response to any anticipated, perceived or felt issue.
Prejudice is harder to tackle, as is human nature’s aversion to change, but we always aim to put forward a transparent view of beaver impacts including challenges and invite inclusive debate across our work. But as I said, Beaver Trust’s experience in England to date has been a pretty positive one with the landowning and farming community.
North American beaver on lodge by Ben Goldfarb
3. A core component of your work moving forward is set to focus on river buffer zones – allowing nature to recover and regenerate around river banks. Can you tell us more about this?
Yes, and it links directly to the previous question. If we want beavers to achieve all the good flood and drought mitigation, water filtering and biodiverse habitat restoration we anticipate, they will need space to operate. Their dams and canals can revert streams and smaller rivers into meandering wetlands, however, depending on the location this could quickly cause issues. In a sense, we need to make our rivers fit for beavers (and all other life that should exist there), without placing further burden on farmers trying to do the right thing and produce affordable food.
The key is space for nature. Stepping back from the margins and allowing the naturally high biodiversity that should exist there to thrive. Beaver Trust is therefore working in partnership with leading environmental NGOs on a programme for riparian buffer zones along whole catchments. We need a greater vision than a small strip of river bank, and are aiming for 10-20m+ zones, but it could even mean whole floodplains are set aside for natural processes.
Farmers will then be paid for nature’s recovery and we’d like to see farm clusters able to apply, allowing greater scope for whole catchment restoration and connected nature corridors. For the programme to succeed and feed into ELMs we need a simple payment mechanism and not just another layer to add to the farmer’s list of environmental expectations. We need a broad partnership, including Defra, to think systemically so that it becomes easier for land managers to make good environmental decisions without hidden costs to their operations.
If we allow rivers the space to find their natural course and re-establish meanders, scrub and woodland to naturally regenerate, beavers to bring back freshwater habitat and increase species abundance, then we will start to see real resilience along our river network ready to help us as climate pressures hit harder and stronger.
We hope to see a bold and ambitious government strategy for beavers, but given their catchment-scale impacts we should be thinking systemically with related policies. The great thing about river buffers is that it could take relatively little land out of production – but these edges are where all the great biodiversity happens. So it’s a win-win for conservation and farming if we make it easier and practical to sign up.
4. Are there any other big projects that the Trust is going to be working on in the near future?
Our main policy campaign this year will be river buffers, working in partnership with the National Trust, Rivers Trust and Woodland Trust. As part of this we are working on a follow-up documentary film to the award-winning ‘Beavers Without Borders’ (2020) that explores the challenges and opportunities for river buffers, interviewing experts on a variety of areas including farming, angling, public access and biodiversity. But we will also continue our core policy ambition convening broad stakeholder working groups on the English Beaver Strategy, which the government is set to consult on this summer.
In the restoration department we are supporting a groundbreaking community-led beaver project where a group of local landowners and residents are looking to reintroduce beavers as a flood mitigation strategy along the whole catchment.
Beaver Trust has also recently been awarded the call off contract for the beaver management framework in Scotland by NatureScot, so we’ll be gearing up for a busy season at the end of the year. Working alongside landowners experiencing conflicts particularly in prime agricultural areas and looking towards long-term mitigation strategies. This can range from ecological advice, tree protection, dam and burrowing mitigation, to translocation as a last resort. In collaboration with the animal care and veterinary team at Five Sisters Zoo, beavers are health screened and rehomed to licenced projects elsewhere in the country.
Our communications and outreach team is working hard across a number of projects, including The Lodge Cast podcast series, radio and other media. We also have several education initiatives under way but one particularly exciting partnership is for a new beaver enclosure and educational learning hub at a major tourist attraction in the South West. The key driver of this project is improving nature connection with children from socially and economically deprived backgrounds, and people with reduced mobility and sensory and cognitive disabilities. We have not yet secured funding for this project so cannot say further than that at present but it exemplifies Beaver Trust’s ambition to educate and connect people beyond wildlife enthusiasts with the joys that beaver wetlands offer.
Dam at WVF by James Wallace
5. The Covid pandemic has had a huge impact on individuals and organisations. How has the Beaver Trust been affected over the past year, and how have you dealt with these unforeseen challenges?
It’s been a genuinely interesting and challenging time to be part of a new charity: Lockdown arrived while Beaver Trust was really getting its roots down, there was no furlough option for us at the time as we were so new, plus we were a very small team and some of us had the challenge of home education to navigate (torturous for both teacher and pupil)!
But it has made us a really strong and resilient team, given our remote locations. I think one of the great strengths of Beaver Trust people is their wholehearted approach to work: Real conversations, emotional wellbeing and individual authenticity is encouraged and, for us, it works well. It also helped immensely to have a powerful passion for nature restoration and climate action shared within the team, enough to keep everyone motivated, and to have such incredible support for beavers from the public. They are already a much-loved animal and as such we’ve received reams of very humbling offers of voluntary support from all sorts of highly experienced individuals. We are grateful for every single one.
6. Thank you so much for your time in chatting to us. One final question: for anyone interested in getting involved in beaver conservation within Britain, how would you suggest that they go about this?
Beaver dam by Eva Bishop
It’s a great question and I’d start by saying it’s time to break the system: forget career silos, land and wildlife needs ALL of us – it is everyone’s countryside, rivers are everyone’s source of freshwater and wildlife should be part of everyone’s mental health and wellbeing whether through paid employment, voluntary time or new cultural norms. To use a small example, how do we make litter picking fun? Anyone can care for their local patch and help conserve it. I recently saw a wine bottle used in the construction of a beaver dam, something we can avoid by everyone taking part.
But I also think the conservation sector can be quite intimidating and packed with such expertise it’s hard to infiltrate, so I’d encourage people to follow their interest and speak up, even if you’re not sure you tick every box. Within beaver restoration, specific roles will emerge within charities and across communities as wild populations expand, specific training programmes will be available (for example beaver management through CIEEM), keep an eye out for new job opportunities with Beaver Trust, Wildlife Trusts, Woodland Trusts and others.
Another idea would be to join in with some citizen science on collecting information on beavers and river impacts. This doesn’t need to be specific to Beaver Trust either – there’s the Freshwater Habitats Trust, or the Mammal Society which has a mammal tracker app, all of which could help support wider conservation work.
If you’re already in employment, why not talk to your company about funding nature’s restoration and helping scale the impact of nature restoration charities. One of the biggest challenges to conservation is the funding and resources to expand operations.
On a purely fun level, Beaver Trust also hosts regular outreach activities like May’s poetry competition, last year’s photography competition, the monthly podcast, online quizzes and various other celebrations, so please get in touch and join in. Write us a blog and we might be able to publish it on our website. The more these communications are shared, the more people will understand what a beaver is and be accepting of its arrival. Conserving nature as a whole will benefit all the species that rely on it, including humans.
You can find out more about the Beaver Trust from their website and by following them on Facebook and Twitter.
To learn more about the Beaver Trust’s conservation projects, you can read the Introducing: Beaver Trust article included in the Spring 2021 issue of Conservation Land Management magazine. In this article, Eva Bishop discuss how the Beaver Trust came to be, what it is trying to achieve, and the exciting projects it has been involved in.
The lengthening evenings of late Spring or early Summer are an ideal time for an evening wildlife walk. Now the vegetation has become more lush and the air has become warmer, the insects form in thicker clouds and the bats are now on the wing.
The Sharpham estate is a 550-acre area which runs alongside the River Dart just outside Totnes. This historic landscape is home to the Sharpham Trust, an educational charity whose Wild for People project aims to rewild areas of the estate and enhance biodiversity in the region. To read more about the history of the Sharpham Estate and the launch of their Wild for People project, click here.
A few of us from NHBS walked up to the Sharpham estate where we met a group of Ambios’s conservation volunteers and trainees for an evening wildlife walk. We brought a selection of bat detectors with us and explained the differences between our most popular professional detectors. We distributed any active bat detectors among the volunteers and showed them how each type worked. We then left the farm just as dusk was settling with detectors armed and ready.
As we wandered the footpaths and fields of the estate, we watched several Noctule and Leisler’s bats commute high above the fields, along with some Common and Soprano pipistrelles zipping along the hedgeline foraging.
We then cut across a field to a dead tree where NHBS Wildlife Equipment Specialist Josh had previously set some insect bait traps. The traps were baited with a mix of banana and beer and had been set in the hopes of catching saproxylic beetles emerging from dead wood.
Josh has also been monitoring the beetle diversity of Sharpham through a series of pitfall traps placed across the estate, although prior to our walk they had unfortunately been closed due to heavy rain. Unfortunately no beetles were found in the traps this time, but we did spot a variety of species scurrying along the field and forest paths including Anchomenus dorsalis, Dromius agilis and Staphylinus dimidiaticornis, along with the very common Nebria brevicollis (gazelle beetle) and Pterostichus madidus (black clock beetle).
Once it was much darker, on our way back up to the farm, we also had the pleasure of listening to the alien-like call of a sitting Lesser Horseshoe bat that was perched just meters away from the group. It made for an exciting end to the walk and we hope to detect even more bat species through passive detector recordings.
The Elekon Batlogger M2 is a sophisticated bat detector, designed for use in active transect surveys and bat walks. The detector is ergonomically designed and compact in its build. Unlike the Batlogger M, the replaceable microphone is set back within the casing, reducing the chance of breakages if accidentally dropped.
How we tested
The screen display was bright and easy to view in the dark. The main screen shows the current recording time and frequency, as well as amplitude and harmonic structure of the previous bat call, the time since the last sequence and the species suggestion for that recording. The other recorded information can be accessed by pressing the left and right buttons to switch screen displays, allowing for an uncluttered screen and fewer distractions.
We recorded multiple calls including over 60 calls during one 30 minute survey. We were impressed with the quality of the recordings and the lack of ambient noise assisted in the identification of calls. It is worth noting that the M2 uses a SiSonic microphone, whereas the older Batlogger M uses an FG Knowles microphone, so experienced Batlogger M users may notice a slight difference in their recordings.
RHS The Little Book of Wild Gardening
Gardening for Bumblebees
Acoustic detection is a popular and widespread method of environmental assessment, and its use is increasing, driven by the development of increasingly accessible and sophisticated detection devices. 
Here we review the Anabat Scout from Titley Scientific. The Scout is an easy to use active bat detector that offers excellent quality live audio and recording, plus many handy surveying features and durability that sets it apart from other detectors. It uses heterodyne, auto-heterodyne and frequency division audio that can be recorded in either full spectrum or zero crossing files.
