Hoopoe – A blog by nhbs – Page 71 – The NHBS Conservation Hub

What’s new for 2016 – Torch news

The LED Lenser P17.2 and H7.2 are just two additions to our lighting range.

Ecologists use torches for a wide range of applications including newt surveys, for note taking and safety during nocturnal surveys and to look for roosting bats and other creatures within lofts and other confined spaces. Each application requires different things from the torch – high power for newt surveys, a red filter to preserve night vision, light weight and / or hands free operation to reduce fatigue, a long operating time, lower power settings to reduce disturbance and an LED bulb to reduce heat output. So far, we know of no single torch that combines all of these attributes in an affordable package but progress is being made. Here we introduce three new torches from the LED Lenser range that we have heard great things about and one new lamp and two new torches from Cluson.

The LED Lenser P7.2 is a hugely popular, general purpose handheld LED torch. Despite its compact size (it weighs just 175g!) it is very powerful, boasting 320 lumens when used at its highest setting. It has a robust but ergonomically designed weatherproof casing (IPX4 rating) and is great for prolonged use in the field. At the high setting (320 lumens, 260m beam) four good AAA batteries will last for two hours and at the lowest power setting (40 lumens, 100m beam) the batteries will last for 50 hours.

The LED Lenser P17.2 has a higher specification than the LED Lenser P7.2 with a powerful beam of 450 lumens that can reach 420m. It is constructed from tough, aircraft-grade aluminium with a dust and water resistant coating (IPX54 rating) and a smart, anti-slip black matte finish. The P17.2 has a fast focusing mechanism which enables the use of one hand to hold the torch and focus the beam simultaneously. Power, Low Power and Boost modes can be selected using a large dynamic switch that is designed for single handed use and for users wearing gloves. Perfect for carrying out newt surveys. Three D-cell alkaline batteries will power the P17.2 for 300 hours at the lowest setting (50 lumens, 140m beam) and for an impressive 30 hours on the highest setting (450 lumens, 420m beam).

We have also added the LED Lenser H7.2 Head Torch – a great little head torch with an extremely powerful 250 lumen maximum beam. Its lightweight (165g) and clever design make this torch extremely comfortable to wear and easy to use. Choose between eight light functions ranging from the most powerful 250 lumen, 160m beam setting to a comfortable 20 lumen setting for reading and note taking. Four good quality AAA batteries will power this head torch for seven hours on the maximum setting and for 60 hours on the lowest setting.

The Cluson CB3 LED Lamp combines the legendary features of the CB1 and CB2 High-Power Lamps with an LED lighting system. The 25W bulb uses half the power of the 50W Xenon bulb in the CB2 and produces an impressive 750m beam and four hours of continuous illumination (compared with just 1.5 hours for the CB2). For those of you that already own a CB2 the great thing is that you can buy the new lamp head on its own – more than doubling the performance of your old CB2 for a fraction of the cost of a new lamp.

The RE1T Red Eye and the Pro Scanner ML1000 Torches from Cluson use the same aircraft grade alloy body and rechargeable Lithium-ion batteries to produce two lightweight (190g) and robust torches that are perfect for surveys. The RE1T includes a red CREE LED giving a 300m beam of red light for two hours on the high power setting (10 hours on low power) and would be great for spotting badgers. The ML1000 also uses a CREE LED to produce a 300m beam of intense white light (1000 lumens), perfect for newt surveys although the battery life at full power is fairly short at 1¼ hours (three hours at low power). One set of Lithium-ion batteries and a charger are included, spare batteries can be bought separately.

How to choose a nest box camera

Bird Boxes — Installing a camera into a bird box is a great way to keep an eye on the nesting birds in your garden. Image by Simone Webber.

Deciding which nest box camera to choose involves a complicated tiptoe through competing technologies and equipment. Before you start watching birds you have to decide what sort of system is best for you and, crucially, how much money to spend.

The first question you need to consider is whether to choose a wired or wireless system.

Wired systems have a cable running from the nest box back to your house or classroom, which carries both power and the television signal. This results in excellent image quality but may not be ideal if you have children or pets in your garden, or if a cable running to your bird box will interfere with the gardening. You will also need to feed the cable into your house, either by drilling a hole in the wall or by feeding it through an open window.

Wireless systems do not require a cable to run between the bird box and the television but instead transmit images to a small receiver situated inside the house. However, a power supply will still be required for the camera (i.e. from a shed or outbuilding) and the signal can be compromised by other wireless devices in the area or by trees and other structures between the nest box and the house.

Next you will need to consider whether you require a complete kit or just the camera.

If you are new to this particular aspect of watching and listening to birds, a complete kit, such as the Nest Box Camera Starter Kit is a good and economical choice. This starter kit includes a bird box with a camera mounted in the roof, which provides colour footage during the day and black and white at night. A 30 metre cable plugs into your television and supplies the camera with power. Another option is the Gardenature Nest Box Camera System, which includes a bespoke red cedar nest box made to RSPB and BTO guidelines. A small sliding drawer at the top of the box houses the Sony CCD camera, which adjusts automatically depending on light levels. A 30 metre cable connects the camera to your television.

For the handyman or woman who wants to put a system together themselves, either in a bespoke or existing nest box, the Nest Box Camera with Night Vision is a good choice. The tiny camera will focus from a few centimetres to roughly 30 metres, with high definition for excellent daytime and night time images. The camera comes with a 30 metre cable and extension cables are available to purchase separately. The Wireless Nest Box Camera Kit is a great option if you want to fit a wireless camera to your own bird box.

What about watching on your computer?

All of the cameras and kits that we sell come with either a cable or wireless receiver that will connect directly to your television. If you want to view or save your footage onto your computer then an additional USB capture device is required. These are available both for Windows and Mac operating systems and come with all the software you require to get started.

Nature Classics Library: an interview with Jon from Little Toller Books

Jon Woolcott of Little Toller at the publisher’s office in Dorset

Little Toller Books was established in 2008 as an imprint of Dovecote Press with the aim to revive lost classics of nature writing and British rural history. The success of their Nature Classics Library, has allowed them the independence to follow their inspiration in terms of the projects they pursue and they are now a leading voice in nature publishing. We asked Jon Woolcott of Little Toller Books about the Nature Classics Library.

The books are beautifully designed – what was the original inspiration behind the Nature Classics Library?

Thank you, that’s nice to hear – we work really hard at the design of the books, it strikes us that a book should be a beautiful object, and reflect the quality of the writing. The founders and co-owners of Little Toller, Adrian and Gracie Cooper, moved to Dorset but when they wanted to explore more about the country around their new home they found many of the books they wanted to read were no longer available. That inspired them to republish the great classics of nature writing – books like The Making of the English Landscape by W G Hoskins and The South Country by Edward Thomas. So Little Toller Books was born. The list has grown from there.

With introductions by big name authors giving them great general appeal, are you hoping to bring these classics to a new audience?

Indeed – we’re not the first generation to rediscover these great books – and bringing authors like William Boyd, Robert Macfarlane and Carol Klein to them makes a big difference. We also use artists to complement the writing – the obvious example is Ravilious on our edition of The Natural History of Selborne by Gilbert White, but we use artists to illustrate our monograph series.

Eric Ravilious illustration fromThe Natural History of Selborne

How do you choose the books that end up on the list?

We’re a tiny team (there are just four of us at Little Toller) so we work together but ultimately Adrian chooses the books – it’s based on his taste and a sense of what readers are looking for, but always with the goal of exploring nature and our relationship with landscape.

If you could gain rights to publish any book from the history of nature writing, what would it be, and why?

We’ve always got a wish-list on the go! We’d love to publish Tarka the Otter of course (we already publish Williamson’s Salar the Salmon) but a really exciting project would be to publish an anthology of Darwin’s letters recounting his explorations into his local area, and his relationship with his family. As yet, this remains in the pipeline though!

Do you remember the first natural history book that you enjoyed?

At Little Toller we all have our favourites, books that made an enormous difference to the way we felt or thought about nature. Speaking just for me I would highlight a book we don’t (yet!) publish – Bevis by Richard Jefferies. It’s not really a natural history book – ostensibly it’s a children’s book in the Swallows and Amazons tradition but written earlier. Jefferies brilliantly articulates the feelings of a boy as he explores the landscape. Jefferies was an early exponent of what we now call nature writing and I remember being captivated by his style. Adrian would choose On the Origin of Species because it’s so important, but for pure enjoyment he would have to go for Gerald Durrell’s My Family and Other Animals (editorial note: available as part of The Corfu Trilogy).

What do you think characterises great nature writing?

Oh, that’s a difficult question – each writer brings something new – but it’s characterised by a deep understanding of the subject combined with wonderful writing. A sense of the personal reaction to the natural world is imperative – we don’t publish text books but instead those which bring the reader close to the subject.

Little Toller also publishes new writing, with Horatio Clare’s Orison for a Curlew just out. What are you looking for in potential new publications like this?

We look for originality, for subjects which readers will love, and for wonderful writing. It’s led us to publish Oliver Rackham, Iain Sinclair and Richard Skelton this year alone.

What does the future have in store for Little Toller and the Nature Classics Library – any secrets you can let us in on?

We’re always looking to expand what we do – for instance we have two short films on our website about two of our books made by the authors – Iain Sinclair’s Black Apples of Gower and Richard Skelton’s Beyond the Fell Wall – and Andrew Kotting made Iain’s film with him. We’re tiny so we can be really flexible in what we publish but we’re especially excited by In Pursuit of Spring by Edward Thomas – which will have Thomas’ photographs from 1913 taken along the journey, published for the very first time – coming in March next year. We’re also looking forward to Cheryl Tipp’s book on the sounds of the sea. Many of NHBS’s fans will know her – she’s the Wildlife Sounds Curator at the British Library. And we have new books in the pipeline from Tim Dee, Dexter Petley and Horatio Clare, as well as new Nature Classics from R M Lockley and others. We’re also continuing to put our monographs into paperback as we have just done with The Ash Tree. We’re very busy! But we’re enormously heartened by the reaction to our books.

Browse the full list of books in Little Toller’s Nature Classics Library at NHBS

What’s new for 2016 – Bat detector news

Five new bat detectors will become available in 2016 – two new models in the Song Meter family of bat detectors from Wildlife Acoustics, two new passive detectors from the Swiss manufacturer Elekon and the long anticipated Anabat Walkabout. Here we will give you a quick round-up of the key features of each new detector along with news of several detectors which will no longer be available. We will also introduce an exciting new BatCounter and camera trigger.

Wildlife Acoustics have brought out a new detector aimed squarely at the consultancy market – the SM4BAT. The SM4BAT is available in two versions – full spectrum (SM4BAT FS) and zero crossing (SM4BAT ZC). Both come in the same dark green plastic case (a bit like a Bushnell Natureview Trail Camera) which is weatherproof, slightly smaller and lighter than the SM2BAT+ and can be padlocked shut to prevent anyone tampering with the detector. Both use the SMM-U1 microphone which was designed originally for sale with the SM3BAT detector. They are also programmable and will record on a single channel for around 30 nights using four D-cell batteries.

Wildlife Acoustics have also announced that they are phasing out the EM3+ and the SMZC, which are being replaced by the Echo Meter Touch and the SM4BAT ZC respectively.

Batlogger C and Batlogger A — The Batlogger C (left) and Batlogger A (right) offer solutions for a variety of bat survey situations.

Elekon have released two new passive detectors within the last few months which are based around the very highly regarded Batlogger M handheld detector. The Batlogger C is probably the highest specification bat detector on the market – it has everything you would expect from a high end passive detector including programmable recording schedules, fully weatherproof enclosure, and high quality full spectrum recordings as well as many extras. These include optional sms and/or email messages reporting the status of the unit and the number of recordings made as well as the amount of power remaining. Furthermore, because the Batlogger C also has in-built GPS it can send you an alert if the unit is moved. A wide range of power options are available: a 50 hour rechargeable battery is included and there is space for a second. Mains power is also an option as is solar power which requires the addition of the Batlogger C solar panel. When used with two 50 hour batteries, just half a day of sun in every 10 days should be enough to keep the Batlogger C powered indefinitely.

Also from Elekon, the Batlogger A is a miniaturised passive detector. It is programmable and will record for up to 30 hours on eight AA batteries (e.g. three 10 hour nights). The Batlogger A is housed within a small weatherproof enclosure and includes a Knowles FG microphone on a 2m extension cable.

The Anabat Walkabout, a handheld detector for transects and roost emergence surveys is also expected for the 2016 season. This touch screen Android tablet based detector not only records any passing bats but also lets you view the sonogram in real time in both full spectrum and zero crossing formats. A GPS, lux-meter, thermometer and humidity sensor are all in-built so not only will each call be geo-tagged but you will also be able to collect the full range of environmental data for each transect without needing any additional tools. A fully charged unit will last for around 8 hours.

The BatCounter has the potential to be a very useful tool for both researchers and consultants. It uses a network of infrared beams to count, and log the direction of movement of bats moving through a detection area of 76 x 35cm (standard model) or 36 x 35cm (tree model). It has a GSM function that can send daily reports via text or email and will run for three days on eight AA batteries or for much longer periods using a 12V battery. You can also connect a Nikon or Canon DSLR camera and take pictures of the bats as they pass through the Batcounter.

Coming up in 2016: NHBS Bat Survey Training Course with Volker Runkel of EcoObs

UPDATE 7th MARCH 2016 – The Bat Survey Training Course has now been cancelled.

The use of passive monitoring to assess bat activity has important implications for how we work with the vast amounts of accumulated data, and automation now plays a crucial role in dealing with datasets which often contain thousands of recordings.

This bat survey training course has been designed to give you insights into the how-to of passive acoustic bat detection and call analysis, including its pitfalls. It will give you the skills to conduct passive acoustic bat surveys with confidence and to analyse your results in the most efficient and accurate way.

Topics covered will include: Why and where do we listen for bats, how to detect bats, signal analysis, bat call identification and working with large datasets. It will also include a short introduction to the Batcorder system.

The course will be held at the Preston Montford FSC Centre in Shropshire on 9th-10th April 2016.

It will involve a combination of classroom-based learning and fieldwork and will be led by Volker Runkel from the German company ecoObs, manufacturers of the Batcorder system.

Book your place on this course today

Naturalist, artist and author Steven Falk on his new field guide to bees

Naturalist and wildlife artist Steven Falk has had a diverse career with wildlife and conservation, including working as an entomologist with Nature Conservancy Council, and as natural history keeper for major museums. He is now Entomologist and Invertebrate Specialist at UK invertebrate conservation organisation Buglife. His new Field Guide to the Bees of Great Britain and Ireland will be published by British Wildlife Publishing next month.

Tell us about your role at Buglife.
At Buglife, I have quite a diverse role. I provide information and advice to colleagues, external enquirers and a plethora of external organisations. I’ve been particularly involved with overseeing the production of new red lists for assorted invertebrate groups, also providing feedback to the various national pollinator strategies, new agri-environment schemes, plus helping to develop projects for some of our most endangered invertebrate species. We also have a consultancy now, Buglife Services, which carries out and coordinates invertebrate surveys all over Britain. We’ve just done an exciting survey of the A30 and A38 in Devon and Cornwall. We need more understanding of road verge invertebrates, especially pollinators.

How did you come to write this landmark identification guide to all the bees of Britain and Ireland?
I was approached by Andrew Branson in 2012 and was initially quite reluctant, because you cannot use a traditional field guide approach for bees, as many cannot be identified to species level in the field (they require the taking of a specimen for critical examination under a microscope) and it is crucial that we keep the national dataset (run by BWARS) clean and reliable by being honest about where the limits of field identification lie. So I agreed to write it on the basis that it covered all 275 species, had reliable keys, and could appeal to both hardcore recorders and general naturalists. I knew this was feasible, because we had faced the same challenge with the seminal book British Hoverflies (Stubbs & Falk, 1983, 2002). So it is a field guide in the loose sense – it will help you to recognise much of what you see in the field, but also indicate at which point you need to take specimens and put them under a microscope. But you don’t need to collect bees or have a microscope to enjoy the book – we made sure of that.

There is growing concern about the conservation status of bees – how are our bees getting on, and how might the publication of this book help them?
Yes, we need to be concerned about bees. We have already lost 25 species and several more are teetering on the edge of extinction. Good bee habitat continues to be lost. Brownfield land came to the rescue last century, but most of that has now been developed or lost its flowery early successional stages, which is what so many bees need. The research being carried out on pesticides such as neonicotinioids is also pretty disturbing – check out the work by Prof. Dave Goulson at Sussex University. It seems to be affecting bee numbers in many parts of the country. The national pollinator strategies being published by UK member states are a call to arms – let’s get monitoring bees. But the emphasis is on developing citizen science to achieve some of this, because there is little funding. High quality amateur recording is part of this plan, and Britain’s strong tradition of this makes it a realistic proposition. But the last comprehensive coverage of British bees was Saunders, 1896, and it has been the lack of modern ID literature that has held bee recording back. Field Guide to the Bees of Great Britain and Ireland, and the supporting web feature (embedded in my Flickr site) will hopefully fix this!

Your career as a wildlife artist began early – you worked on the colour plates for Alan Stubb’s guide to British Hoverflies when you were just a teenager. How did this collaboration come about?
I pinned some bumblebees I had caught near my home in North London when I was 12. Half of them turned out to be bee-like hoverflies, and that started a fascination with hoverflies. The following summer holiday, I went out with a net almost every day, and seemed to find a new type of hoverfly daily. I was totally hooked on them, and I painted things that fascinated me, including those hoverflies. I exhibited some hoverfly artwork at the 1976 AES Exhibition in Hampstead, and met Alan Stubbs who told me he was writing a new guide to hoverflies. I said I wanted to do the artwork (I was only 14), and the rest is history. It took 3 years of evenings, and I think I was 17 when I finished it. I’m very proud of those plates, and you can see how my style develops (plate 8 was the first and plate 7 was the last – you can see a lampshade reflection in the early ones!).

Do we see any of your artwork in this book?
Sadly not, my eyesight is not great these days and I do very little drawing and painting now. But the British Wildlife Publishing ‘house artist’ is the great Richard Lewington, and he’s done a magnificent job. The bumblebee plates in particular, are just stunning, the best ever produced.

What sort of techniques do you use to produce your artwork – which is strikingly realistic and very detailed?
I painted birds a lot as a young child and was very aware of the bird artists of the time and their styles, people like Basil Ede, Charles Tunnicliffe and Robert Gillmor. I particularly liked the detail and photo-realism of Basil Ede’s work and became aware that he used gouache. So I started to use gouache and preferred it to watercolour. I’d often start with a black silhouette and build up the colour and texture on top of this, which is the opposite of watercolour painting. But others, like Denys Ovendon and Richard Lewington, show what can be done with watercolour, so it’s just a taste thing. For really intense or subtle colours, I’d need to use watercolours, because they produce a much larger colour pallete than gouache. Richard knows his watercolours – you need to if you want to tackle butterflies like blues, coppers and purple emperors. I’m possibly more proud of my black and white illustrations than my colour work. Here I was most influenced by the likes A. J. E. Terzi and Arthur Smith, house artists for the Natural History Museum. Their use of cross-hatching and stippling is so skillful, and I’ve tried to emulate this in my pen and ink artwork. Never use parallel lines in cross hatching!

Any future interesting projects coming up that you can tell us about – artistic, or conservation-based?
There are many more books I’d like to write, especially for wasps and assorted fly groups. It’s not just the subject, it’s the approach. I like getting into the mindset of the beginner and finding the right language and approach. We need to get more people recording invertebrates. I like the double-pronged approach of books plus web resources, and I have a popular and ever-expanding Flickr site that greatly facilitates the identification of many invertebrate groups. On the conservation front, I’m keen to continue promoting understanding of pollinators and to increase the effectiveness of agri-environment schemes. Invertebrate conservation is in my blood and I’ll be pursuing it to the very end in one form or another. I might even try illustrating again one day if I can find the right glasses!

Order your copy of the Field Guide to the Bees of Great Britain and Ireland
Visit Steven Falk’s website

Interview with botanist James Byng, author of The Gymnosperms Handbook

James Byng is the author of the new Gymnosperms Handbook and a founding member of Plant Gateway, the botany organisation that published this, and his previous book, The Flowering Plants Handbook (out of print – new edition pending). In this interview he tells us about his work with Plant Gateway, raising the profile and accessibility of plant research, his own work with the genus Syzygium, and a day in the life of a working botanist.

You are a founding member of the Plant Gateway team. What is the vision for this botany organisation?

Taxonomic research is an underfunded and underappreciated branch of science and so few plant taxonomists are employed today in universities, and most national botanical institutions are cutting staff. However, the need to document the world’s species diversity has never been greater with as many as a fifth of all known plant species estimated to be threatened with extinction.

We believe at Plant Gateway an important step in slowing the biodiversity crisis is making plants more relevant and more accessible to people. It sounds simple but plant research in general is never quite appreciated as much as research on animals or in other scientific disciplines. But plants are fundamental for our own existence and continued survival on this planet, and we still barely know anything about most of them. Plant Gateway was founded for passionate like-minded taxonomists to make sense of the complicated botanical literature by publishing practical literature, running affordable and engaging identification courses, and undertaking taxonomic research with the aim of bringing it to a wider audience and making significant strides in our knowledge.

Who are the Plant Gateway courses for and how can they get involved?

Whilst training to be a plant taxonomist I witnessed over the years that plant identification skills were rarely being taught at universities anymore despite there still being a huge demand. Even though several courses exist which teach these skills, many of the courses are very expensive and/or taught too much from the specialist’s point of view which scares people off. Our courses are designed for everybody and anybody whatever a participant’s botanical background – all you need is an interest and love for plants! On past courses we have had undergraduate and postgraduate students, university professors and lecturers, horticulturalists, ecologists, Friends of Botanical Gardens and gardeners. We run several 1-day identification courses all over the UK in May and June, and a week long course in Tenerife around Easter time in 2016. Places on these courses can be reserved on our website.

The Gymnosperms Handbook is the second publication from Plant Gateway. Who is this book aimed at?

The Gymnosperms Handbook is a concise introduction to identifying extant gymnosperms of the world. It is aimed at both specialists and non-specialists; ranging from experienced botanists, ecologists, horticulturalists, biologists and gardeners to students and those people who are learning about and interested in conifers, cypresses and other gymnosperms because they see them in their local parks and forests. So the handbook is aimed for everybody whatever their background.

Part of your own research is focused on the systematics of Syzygium (Myrtaceae). What led you to this particular genus?

In 2007 I was an undergraduate at the University of Aberdeen when I first encountered the genus Syzygium in Zambia while undertaking ecological fieldwork. Since then I have been intrigued by the genus as most botanists seem scared by the sheer number of (known and unknown) species and the difficulty in identifying them due to the seemingly poor diagnostic characters which separate species. The genus is famous for containing the commercial clove (Syzygium aromaticum) and is now the largest tree genus in the world with over 1,200 species. I am now leading a project, with collaborators in the USA, Australia, Africa and Asia, to unravel evolutionary relationships of Syzygium and to document all species in a global monograph.

What does a working day as a botanical researcher look like for you?

A typical working day for a plant taxonomist in the twenty first century varies from week to week. Most of my time is spent with dried plant collections, housed in herbaria, where I sort through specimens collected from past and present field expeditions and document and describe species diversity. I also spend time collecting new data and plants in the field, usually in the tropics, and undertaking lab work where I extract and amplify DNA to understand evolutionary histories. Lastly, but perhaps most importantly(!), I spend time in front of the computer writing up my findings in the form of scientific papers, reports and books. It can be a combination of enjoyment and stress but once I finish a piece of work it makes it all feel worthwhile.

What’s next in line for publication from Plant Gateway?

One of the next titles in our practical handbook series will be a revised second edition of The Flowering Plants Handbook which will include notes on all flowering plant genera, more images, and will follow the soon to be published Angiosperm Phylogeny Group (APG) IV classification system. Also, there will be a practical handbook on ferns and their allies co-authored with my Plant Gateway colleague, and leading fern specialist, Dr Maarten Christenhusz.

Find our more about the Gymnosperms Handbook

The NHBS guide to buying a hand lens

The possession of a hand lens is one of the defining characteristics of a naturalist.

We use them for everything from peering at beetle genitalia and examining floral characters, to examining the arrangement of teeth in small mammal jaw bones. There are a wide variety of hand lenses on the market so how do you decide which lens is best for you? This article contains all the information you need to make an informed choice about which hand lens is most appropriate.

Glass versus plastic lens?

The optical lens in a hand lens can be made from glass or plastic – the plastic lenses are generally more affordable and lighter but are of lower optical quality and more difficult to clean. Good plastic hand lenses, such as the Plastic Double Magnifier, are perfect for youth groups and schools.

How many optical elements?

Canon 400mm

An element is an individual piece of glass within a lens. When you look through a high quality camera lens you will typically be viewing what’s in front of the lens through four to six lens elements, as well as other elements used for focusing and zooming (see image below right).

Hand lenses are constructed with one (singlet), two (doublet) or three (triplet) lens elements. Each element is specially shaped to correct for a particular type of optical distortion so the more elements, the higher quality the image.

Magnification

A 10x magnification hand lens will be more than adequate for most purposes. Higher magnification lenses tend to be harder to use but are very useful for viewing extremely small objects. If you are unsure of which magnification you need, or think you may need several different lenses, you should have a look at the x10 and x20 Duel Singlet Loupe or even the x3, x4 and x5 Triple Loupe.

Lens diameter

Large diameter lenses provide a wider field of view which means that they are easier to use but they are slightly more expensive to produce.

How hand lenses are named

Hand lenses are named like binoculars, with both the lens diameter and the magnification included in the name. e.g. the Opticron Hand lens, 23mm, 10x magnification has a 23mm diameter lens and provides 10x magnification.

Using your hand lens

Finally, a quick note on hand lens technique. To use your hand lens correctly (this is particularly important when using high magnification lenses) hold the lens close to your eye and then either a) move the subject closer to your eye until it comes in to focus or b) move your head (and the hand lens) closer to the subject until it comes into focus. It’s easy with a little practice so don’t get put off if you find a new hand lens difficult at first. Expect to get close up to what you’re examining – it’s quite common to see naturalists crawling around on the ground to get close to a plant they’re identifying.

Keeping your hand lens safe

It can be very hard to find a much-loved hand lens dropped in long grass or woodland. To prevent this traumatic experience, we recommend a lanyard for your hand lens – this has two functions: a) if you have it round your neck you won’t drop it, and b) if you put it down somewhere the bright blue lanyard is easy to spot.

The table below provides a guide to the hand lenses sold by NHBS. More information and specifications of each can be found on the website.

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Introducing the new SM4BAT from Wildlife Acoustics

The new SM4BAT range of passive bat detectors from Wildlife Acoustics was announced at the 2015 Bat Conservation Trust AGM.

The Full Spectrum (FS) version will allow you to record bat calls in 16-bit resolution at a sample rate of up to 500kHz on a single channel. The Zero Crossing (ZC) version is also single channel and will record zero crossing files. Both are weatherproof, come with a three year warranty and will record for up to 30 (10 hour) nights when powered with four high quality d-cell batteries.

The SM4BAT FS and SM4BAT ZC are now available to order.

Recording Orthoptera using a bat detector

The Great Green Bush Cricket is the largest of the UK Bush Crickets. This beautiful image of a female cricket was taken by Charlie Jackson, from Flickr Creative Commons (CC by 2.0).

The order Orthoptera consists of the grasshoppers and crickets. Although most suited to warmer climates where they are incredibly diverse, in Britain we have 27 native species, as well as a number of non-native, naturalised species. From a very young age we are aware of these beautiful creatures as the sounds they produce fill our countryside with noise.

The characteristic Orthoptera song or “stridulation” is produced either by rubbing the wings together (observed in most of the grasshoppers) or by rubbing a hind leg against a wing (a method used by most crickets). The sound produced is an important part of the courtship ritual and is also used for other types of communication. As the sound created by different species varies significantly, studying these calls is an excellent way of surveying Orthoptera, and is helpful for finding individuals which can then be identified visually.

Stridulation produces a sound which covers a variety of frequencies – the sound made by grasshoppers is usually audible, but many species of cricket produce a higher ultrasonic frequency which cannot be heard by most humans. The use of a bat detector to listen to these higher frequency songs is an excellent way to listen to those species that we would not ordinarily be able to hear, such as the Speckled Bush Cricket. It also allows us to increase the range at which we can hear the audible ones. Bat detectors are also of use to older surveyors, whose ability to hear higher frequencies has naturally declined.

A simple heterodyne detector is perfect for listening to grasshoppers and crickets – one such as the Magenta Bat 4 or the Batbox IIID is ideal as it allows you to tune it to a specific frequency (as opposed to some of the more “intelligent” detectors which will alter it for you). The detector should be set to a frequency of 35-40kHz then all you need to do is sweep it around in different directions until you pick up your subject. It is best to stand in one place while surveying as the noise produced by your footsteps and clothes moving will produce background ultrasound noise which can confuse what you are hearing. The best days for surveying are warm and sunny; crickets are generally crepuscular (active during twilight) whilst grasshoppers are usually active throughout the day.

Unlike bat detecting, where the peak frequency is a key diagnostic feature for determining species, this information is less important for Opthoptera. Of more importance is the pattern and type of sound produced. The Environmental Records Centre of Cornwall and Scilly has a great guide to identifying Orthoptera including a useful information sheet on the use of bat detectors. They also have a collection of sound files of grasshoppers and crickets that you can use to recognise the typical calls produced by many of the species found in Britain.

Why not take along a leaflet or book to aid your identification: The FSC guide to British Grasshoppers and Allied Insects is a handy fold out guide with a useful key. For those looking for a more in depth guide, try the Photographic Guide to the Grasshoppers and Crickets of Britain and Ireland or the Pocket Guide to the Grasshoppers, Crickets and Allied Insects of Britain and Ireland.

Want to know more? Visit the website of the Grasshoppers and Related Insects Recording Scheme of Britain and Ireland where you will find lots of information and can submit your survey results. Or why not download the iRecord Grasshoppers app which is available for iPhone and Android devices.