The NHBS Harp Trap

The NHBS Harp Trap 

Earlier this year we were delighted to launch another exciting product manufactured here at our base in Devon. After a concerted period of design and manufacturing effort by our expert Workshop Team, followed by testing and review by ecological professionals, our NHBS Harp Trap was ready for production. The launch of our product into the wildlife equipment market signals the arrival of the only commercially produced harp trap in Europe. 

What is a Harp Trap? 

A harp trap provides an alternative bat survey method to mist netting or the use of bat detectors. They are particularly useful in situations where bats in flight can be channeled through a natural funnel such as above a water course, a cave or mine entrance or a clear area within a forest. 

Harp traps consist of a frame which is either freestanding or suspended, and supports two to four rows of nylon strings. The bats will fly into the nylon strands and then fall unharmed down into a collecting bag below. The catch bag is made from green cotton canvas that is water resistant and breathable and includes heavy duty clear plastic baffles to prevent the bats from escaping. Unlike mist nets, harp traps do not entangle the bats an it has been reported that they can be more effective for surveying bats, potentially capturing higher numbers of individuals. 

The NHBS Harp Trap

The new NHBS Harp Trap is a three-bank trap, meaning it has three rows of nylon line. Our trap has a catch area of approximately 4mand catch bag which is around 60cm deep.  It folds down neatly into a bespoke carry bag and weighs approximately 15kg-full specifications and dimensions are below. The trap takes two people around 10 minutes to assemble and stands on four sturdy, extendable legs and which can be arranged at the height that you need the trap to be. There is also the option to anchor the harp trap with guy ropes in windy conditions. The trap can also be adapted to be suspended if this is required. 

Our trap has a few innovative features designed to make assembly and disassembly easier. Firstly the strings are wrapped  around a winding mechanism which greatly reduces the stress and time-consuming act of sorting through tangled lines in the dark.

 

There is also an extension under the catch bag, which prevents the bats from flying underneath the trap and this doubles as protection for the component parts as it wraps around the disassembled trap when it is stored in its bag. 

Dimensions:

Catch area: 4m2 approximately
Catch area L x W: 180 x 225cm
Length: 180cm
Catch bag depth: 60cm
Catch bag width: 44cm
Weight: 15kg

Folded dimensions (in carry bag)
Height: 46cm
Length: 200cm
Width: 22cm

Operational dimensions
With legs fully retracted:
Height 314cm
Width (at base): 62cm
Length (at base): 230cm

With legs fully extended:
Height: 372cm
Width (at base): 100cm
Length (at base): 252cm

Testing 

As our harp trap evolved, prototypes were trialed and reviewed by ecology professionals; Professor Fiona Mathews of Sussex University and Neil Middleton of Batability. Their expertise and excellent feedback helped us develop our the harp trap to the point that it was now ready to go live. 

The team at NHBS have done an excellent job in coming up with a new and refreshing approach to harp trapping, which shows many innovative and useful design features.  When testing the equipment we were able to demonstrate that it was quicker/easier to assemble than competitor’s products.  We are happy to recommend this harp trap, and will be ordering one ourselves, to be used during our training courses and for bat-related research.   
Neil Middleton, BatAbility Courses & Tuition

The Law 

Harp traps can only be sold to those who are licensed to use them. If you hold such a licence, we will ask to see a copy of your NE, NRW or SNH licence when you contact us about your purchase. If you are purchasing from overseas, we will request details about your institution and research. 

NHBS Manufacturing

NHBS manufactures marine, freshwater and terrestrial survey tools, all carefully designed to meet the demands of researchers, consultants, public authorities and educators in the environment sector. Made by our team of expert engineers, fabricators and seamstresses, our products have become renowned for their quality, durability and affordability.

Find out more about our manufacturing.

Key accessories for using alongside your harp trap

The Petzl Tikka Headtorch has a 200 lumen beam and a maximum range of  60m. It has five lighting modes with both red and white light. It is powered by 3x AAA batteries (included) and available in four colours.

Price: £28.99 £32.00

 

The Kite LED Loupe Triplet Hand Lens 10 x 21 provides crystal clear images which are enhanced with its ring of LED lights. This product may prove invaluable when trying to identify some of the tiny distinguishing features of certain bat species. 

Price: £41.99 

The A4 Portrait Waterproof Clipboard allows you to write in the field without having to worry about the rain. A waterproof plastic covering system helps to keep your paper dry and can be closed over the clipboard with the strong velcro fastener. 

Price: £22.99

Books 

The Bats of Britain and Europe 

Paperback | Sept 2018 

Price: £23.99 £29.99

The Bat Workers’ Manual 

Paperback | July 2012 

Price: £29.99 

 

Field Guide to Bats of the Amazon 

Paperback |Feb 2018 

Price: £24.99 £29.99

 

Please note that prices are correct at the time of publishing and are subject to change at any time. 

NHBS Guide to Bat Survey Equipment

Common Pipistrelle by Meneer Zjeroen on Flickr

With Spring around the corner and the bat survey season fast approaching, it is a great time to make sure you have everything ready for the busy months ahead. Over the winter we have been busy reviewing our current products, cataloging new products and even designing our own products. Here, we have picked out some exciting new products as well as some old favourites to take a look at.

The NHBS Harp Trap – Coming Soon!

Over the last few months, the NHBS manufacturing team have been working hard on developing the NHBS Harp Trap. We are currently in the process of testing and trialing our harp trap ready for its release in the coming months. Designed and built on-site at our workshop in Totnes, our three-bank harp trap will feature some innovative designs such as a winding line carrier and anti-tangling system that makes assembly and disassembly, easy and efficient. Made mostly from aluminium, the trap is surprisingly lightweight at just 15kg, whilst remaining sturdy and durable during use. The harp trap is 190cm long and has a catch area of about 4m². The catch bag is approximately 60cm deep and its entrance is about 39cm wide. When collapsed, the catch bag wraps around the disassembled frame and is held tightly with Velcro straps so that it can be neatly stored and carried in its bag. Initial feedback on its design and function has been very positive and we are excited to develop our design based upon suggestions from professional bat workers. Our standard trap will be a three bank, but if you would like a bespoke two or four bank trap, please contact us so that we can discuss your requirements.

BTHK Tree-Roost Net

Based on the design by Henry Andrews from the Bat Tree Habitat Key (BTHK) project, the BTHK Tree-Roost net is uniquely designed for trapping bats as they emerge from tree roost sites. The net is set up against a roost site prior to dusk so that it will catch any bats that emerge, keeping them safely in the bag ready for identification, measuring and ringing. The diamond shape of the net head can pivot and collapse inwards to ensure that the net fits flush against any tree, making it safer for bats and easier for surveyors. The net bag is made from fine woven nylon mesh that is soft and will not damage the delicate wings or feet of bats. The net bag can be easily removed for cleaning and features a clear plastic rim that fits around the collar and prevents bats from climbing up and out of the net when it is in place. The length of the handle is 4 meters (breaks down into 3 sections for ease of transport) and the depth of the bag is 1 metre. You may also be interested in the book Bat Roosts in Trees which is a guide to finding tree roosts.

Anabat Scout – Coming Soon!

The Anabat Scout is the latest bat detector by Titley Scientific. Due for release this March, the Scout is designed with UK and European bat biologists in mind and is tailored for active bat surveying. It can record both full spectrum and zero crossing files and stores them on a SD card with every file geo-tagged. The Scout has heterodyne, auto-heterodyne and frequency division audio that can be played through earphones or its own built-in speaker. The in/out bat counter is ideal for emergence surveys and will automatically timestamp and geo-tag every count. The small OLED screen displays crucial information without being too bright or distracting and the Anabat Scout will be compatible with Anabat’s free Anabat Insight software for viewing and analysing your data. Easy to use and versatile, this new detector is set to become popular with bat ecologists who are looking for an active survey detector.

Elekon Batlogger M

The Elekon Batlogger M is great for active surveying and full spectrum recording. The weatherproof FG Knowles microphone has a range of 10–150kHz and can record in 16-bit full spectrum. The Batlogger M also logs the GPS coordinates (via an integrated GPS receiver), and environmental temperature at the time of recording. Different recording settings (scheduled, permanent, or triggered), and different trigger thresholds (for call identification) can be set up and the device comes with its own powerful but user-friendly call analysis software package

Echo Meter Touch 2 Pro

The Echo Meter Touch 2 lets you record, listen to, and identify bat calls in real-time on your iOS or Android device. All you need is your Android or Apple device (see the nhbs.com website for compatible models), your Echo Meter Touch 2 Pro, and the Echo Meter Touch App which is a free download from the iTunes Store or Google Play Store. When plugged in, the Echo Meter Touch 2 enables you to listen to bats in real time, view live sonograms in full colour, record onto your device and identify calls to species level in seconds. If your device has GPS functionality, the Echo Meter Touch will also log the recording location and path of the recording session. There are two versions available in both an iOS version and Android version. Both versions allow you to listen to calls in real time expansion and heterodyne and you can playback in real time expansion, heterodyne or time expansion modes. The trigger sensitivity and sample rate are adjustable and three gain settings allowing users to optimise their detector to their target bat species and ambient conditions.

SM4BAT FS

The SM4BAT FS is a full spectrum detector for passive surveying use. Robust and weatherproof, it will record 16-bit full spectrum calls and can store up to 512GB of data. A versatile scheduling function allows you to set when you want to record and the battery can last up to 450 hours. The SM4BAT FS is easy to fit to a tree or post and is compatible with a variety of accessories such as GPS unit and microphone extension cables. The SMM-U2 ultrasonic microphone is available with the SM4BAT FS and is a highly sensitive microphone that produces high quality, low noise bat recordings over long distances. Easy to set up and producing detailed call recordings for analysis, the SM4BAT FS is ideal for unattended use in the field.

Anabat Swift

The Anabat Swift from Titley Scientific is based on the excellent design of the Anabat Express, but has the advantage of recording in full-spectrum, as well as zero crossing. Users can choose between sample rates of 320 or 500kHz and data is saved onto an SD card. Two SD card slots are available, allowing you to save more bat calls without changing cards. The Swift also has a built-in GPS receiver that automatically sets the clock, calculates sunset and sunrise times and records the location of the device. It will also record automatically from sunrise to sunset every night (based on GPS coordinates) as one of the automatic recording settings.

BatLure

The BatLure can be used as a lure to improve catch rates of bats for survey or research, to attract bats to new artificial roosts such as bat boxes or constructed hibernacula, with bat detectors at training events or prior to bat walks and for calibration of bat detectors. The Batlure can playback sounds with frequencies of up to 100kHz and is capable of playing both real time and time expanded recordings of bat vocalisations. It is very compact and robust and has a tripod attachment mount, making it easy to set-up in your desired location. It plays sounds from an SD card which is supplied complete with several pre-loaded recordings. Users can also add their own recordings onto the card.

Ecotone Ultra Thin Series M mist net for bats

The Ecotone Ultra Thin Series M is ideal for catching bats and is available in 2 mesh sizes. Both are made from nylon (0.8mm monofilament) and have 4 shelves. Available in lengths from 3m to 21m, you can pick the mesh size and length that best suits your survey and situation.

 

Explorer Premium Digital Endoscope Camera

The Explorer Premium Digital Endoscope is lightweight and easy to operate. It can record still images or video on to a microSD / microSDHC card (not included). The screen can be detached whilst the camera is in operation and viewed up to 10m away. The camera head has a diameter of 9mm and the cable is 91cm long, giving easy access to nest boxes, burrows, nests, crevices etc. Lighting levels can be adjusted to minimise disturbance to animals.

Accessories

Below are some accessories that may come in use when surveying bats:

Petzl Actik Headtorch
£39.95

Stainless Steel Hand-Held Counter
£7.50

Animal Handling Gloves
£5.69 5.99

dialMax Vernier Dial Caliper
£29.99

ETI Hygro-Thermo Pocket Sized Hygrometer
£21.95 26.99

Small Mammal Holding Bag
£3.60

Telescopic Inspection Mirror
£14.99 16.99

High Flier Mist Net Support System (for Bats)
 from £695.00

Further Reading

Below are some books that may come in use when surveying bats:

Bat Roosts in Trees£39.99
British Bat Calls £18.99
Bat Surveys for Professional Ecologists£29.99
The Bat Worker’s Manual£17.99

A note on licensing

Please note that in the UK, all bats and their resting or breeding places are protected by law. Any bat survey work must be undertaken by a licensed bat ecologist and when purchasing certain products, we ask you to confirm your lisence or give an appropriate reference. For more information, please visit https://www.gov.uk/government/collections/bat-licences.