NHBS Guide: Where to hang and how to maintain your bat box

Natural roosting sites for bats are in decline due to changes in building standards and countryside management practices. Installing a bat box is a simple and affordable way of providing much needed roost space for a variety of species and now is the ideal time to install one, before bats fully emerge from hibernation. However, placing your bat boxes in the correct location and at the correct height is essential to encourage bats to occupy them. With this in mind, we have put together some answers to the most frequently asked questions about bat boxes – covering where and when to put up your boxes, cleaning and maintenance, and the legalities of checking whether they are occupied.

Which bat box should I purchase?

Bat boxes can be placed in trees, on walls and on or in the brickwork of buildings. To help you choose the most suitable bat box based on where you want to locate it, take a look at our three-part series designed to help you make the right choice:  

 

Top 10 Bat Boxes for Trees and Woodland

Top 10 Bat Boxes for Walls and Fences 

Top 10 Bat Boxes for New Builds and Developments

When is the best time to put up a bat box?

Bat boxes can be installed at any time of year, but they are more likely to be used during their first summer if they are put up before the bats emerge from hibernation in the spring. If you are installing bat boxes as part of an exclusion project from a building, it is best to erect the boxes four to six weeks before the exclusion. 

Schwegler 1FF Bat Boxes

Where should I hang my bat box?

All bat boxes should be positioned at a height of 3-6 metres (the higher the better) in an open, sunny position (6-8 hours of direct sunlight, or in a location where it receives the morning sun if this is not possible). Try to install the bat box where it will not be disturbed by bright lights at night such as porch or security lights. 

The most common location to hang a bat box is on a tree using a strong nail that is at least 85 mm in length. It is important to use aluminium nails, as these will not damage a chainsaw (or chainsaw user) should they be left in the tree when it is felled. For more details on how to hang your bat box to a tree, wall or fence, please read our blog on where to hang and how to maintain your nest box, which, although mainly focused on bird boxes, is equally relevant for bat boxes. 

How do I check whether the box is occupied?

Many bat boxes have an opening at the bottom and do not require any maintenance as the droppings will simply fall out of this space. If cleaning is required it is essential that you ensure that the box is not occupied before carrying out any maintenance. Once bats have inhabited a roost site they may only be disturbed by licensed bat workers. If you are unsure whether your bat box is occupied the best way to check for box occupancy is to observe the box at dusk (15 minutes after sunset for around 30 minutes) to watch for any bats leaving. Additionally, you can look under and nearby the box for guano (bat droppings). If there are bats present, wait until later in the season and then check again. It’s also a good opportunity to use a bat detector to identify the bats in your box – take a look at our guide on bat detecting for beginners.

Large Multi Chamber Bat Box

How do I maintain my bat box?

The best time to clean the majority of bat boxes (those suitable for summer roosts) is during the autumn or winter. Once you have ensured the bat box is not occupied you can open the box and clean out any droppings. Whilst you are cleaning the bat box it is a good idea to look for any damage, as this may mean it is unlikely to be used. The most likely damage will be broken seams around the roof, because the constant heating and cooling during the day can warp the wood slightly. To repair this, we would recommend using a roof sealant. 

Head over to the NHBS website to browse our full range of bat boxes. If you have any other questions or would like further advice, please get in touch with our team of Wildlife Equipment Specialists (email: equipment@nhbs.com or phone +44 (0)1803 865913).

 

Introducing the NHBS Moth Trap

The NHBS Moth Trap is an exciting new lightweight and highly portable Skinner moth trap designed and manufactured onsite at our Devon workshop. It is constructed from lightweight plastic panels covered with a light-coloured nylon material, and is assembled using Velcro. Once assembled the trap container has two panels which help prevent trapped moths escaping. The electrics are added by sliding the light holder into the wall supports.  When fully assembled the trap measures approximately 30cm wide x 30cm deep x 50cm tall, it is mains powered and will run a single 20W Blacklight bulb. A benefit of these bulbs is that they will not shatter in contact with rain, however, like with every moth trap we would advise against using it during adverse weather.

The NHBS Moth Trap is designed with portability in mind. It comes supplied with a lightweight carry bag that you can use to transport and store the trap when not in use. This bag measures approximately 30cm wide and 45cm tall when all trap components are included. The complete trap only weighs around 1.6kg; much lighter than the typical solid plastic assemblies of other Skinner traps.

Butterfly Conservation’s review of the trap

In August 2019 we sent our trap to Phil Sterling, one of Butterfly Conservation’s leading moth scientists and author of the ground-breaking “Field Guide to the Micro-Moths of Great Britain and Ireland”. Phil was kind enough to set out our trap over six different nights and offer his feedback on how it fared.

“The trap is very good, and comparably better in my view than equivalent 20W tube traps on the market currently though I haven’t run comparative studies as such. However, I do regularly run a similar sized black plastic trap with a similar 20W bulb, along with a Robinson 125W mercury vapour trap several metres away, as my standard night time trapping in my garden. Using the NHBS trap in an identical position, the NHBS trap has been surprisingly good, consistently catching more moths than I would expect each time, comparing it with the catches in the black plastic trap.

I like the NHBS Moth trap because it is covered with white nylon, which glows with UV light at night when the light is on. I think this helps attract the moths, and critically, by being fairly light inside the trap itself, the moths readily calm down and rest until morning. I also like the portability of the NHBS trap, and particularly that it doesn’t need a rain shield.

I would definitely recommend this trap.”

Phil Sterling’s haul from a night’s trapping in August

The NHBS Moth Trap is now available on the NHBS store here. We are grateful to Butterfly Conservation and Phil Sterling for their generosity in reviewing our trap.

To view our full range of entomological equipment please visit www.nhbs.com. If you have any questions on moth traps or would like some advice on the best trap for you then please contact us via email at customer.services@nhbs.com or phone on 01803 865913.

How to Choose a Pair of Binoculars

 

With the return of overwintering waders and ducks to the UK, it is a fantastic time to get out with a good pair of binoculars and enjoy the spectacle of thousands of water birds using our estuaries. A good pair of binoculars is an invaluable part of the naturalist’s field kit and they provide some of the most memorable wildlife encounters. There is an overwhelming array of sizes and specifications and it can be difficult to choose between them when purchasing a new pair. In this post we will provide a summary of some of the key features of a pair of binoculars, to help you find the best pair to accompany you on surveys, whilst travelling or when enjoying your local wildlife.

Once you have decided on your budget, there are a few key metrics that will help you decide which pair of binoculars will suit you best. With binoculars it really is worth paying as much as you can afford as the glass, lens coatings and specifications improve with every step up in price. All of the binoculars in the NHBS range are roof prism binoculars, they are all waterproof and come with a case and neck strap.

Magnification

Binocular models generally have two numbers in their description. The first of these relates to the magnification. (For example, 8 x 42 binoculars will have a magnification of 8x). In general, binoculars have a magnification between 8x and 12x. As you would expect, the higher the magnification, the larger objects will appear when looking through them. As magnification increases, the field of view can be reduced and you will need to ensure that you have steady hands or use some kind of support.

Lens Diameter

Larger diameter lenses provide brighter images at dawn and dusk. Photo credit: Paulo Valdivieso – www.flickr.com

The second number in the binocular model description (e.g. 8 x 42) refers to the diameter of the objective lens. Standard size binoculars tend to have objective lenses of 32mm to 42mm whilst lenses in compact binoculars usually measure 25mm. Larger lenses can dramatically improve low light performance and are particularly good for use at dusk or dawn. The trade off is that larger lenses are heavier. The most popular size of binoculars for birdwatching was traditionally 8 x 42, but with advances in manufacture and lens performance, 8 x 32 binoculars now offer fantastic specifications in a more compact body.

Glass Type

The type and quality of glass have a huge impact on image quality. Image by Bicanski via Public Domain Images

The type of glass used to manufacture the lenses can vastly affect the quality of the image. Two types of glass to look out for are extra-low dispersion (ED) and fluoride (FL) glass. These reduce chromatic aberrations giving clearer and sharper colours and reduced colour “fringing”.

 

Fringing is the blurring that can occur between light and dark parts of an image. If your budget allows for an upgrade to ED glass binoculars, you will notice a distinct improvement in clarity compared to binoculars without ED glass. Affordable pairs of ED binoculars include the Hawke Optics Endurance ED, the Nikon Monarch 5 and the Opticron Explorer ED.

Lens and Prism Coatings

The primary difference in performance and the brightness of images between different pairs of binoculars is often due to lens and prism coatings. Light is lost as it travels across every surface inside a pair of binoculars and the aim of a good pair of binoculars is to keep light transmission as high as possible between the objective and the ocular lens. Lens and prism coatings reduce the amount of light that is lost helping to produce a brighter and sharper image. Lenses that are multi-coated have multiple layers of lens coatings. High quality binoculars are fully multi-coated which means that they have multiple layers of coating on all lens surfaces. Roof prism binoculars have a particular problem with “phase shift” where the polarisation angle of the prism causes the light passing through to be split into two slightly out of phase beams. This results in an image which has lower resolution and may look slightly blurred. Prism coatings correct this problem by forcing the split light back into phase. Look out for binoculars with Phase Correction (PC) prism coatings.

Dunlin (Calidris alpina). Photo credit: Ron Knight – www.flickr.com
Key Comparison Metrics

Comparing some of the performance metrics of a pair of binoculars can help when deciding which pair would best suit your purposes. In particular field of view will be useful if you are looking at large landscapes (e.g. whale or sea watching) and close focus is very important if you are looking at insects.

Field of View – The field of view is how wide an image can be seen at a specified distance (usually 1000m). A wide field of view is useful for large landscapes and for fast moving animals. Models with a particularly wide field of view include all of the Kite Optics range, the Opticron Discovery, Traveller ED and Explorer ranges, the Bushnell Prime and Forge ranges and the Swarovski EL and SLC binoculars.

The Opticron Discovery range of binoculars has a fantastic field of view and great close focus.

Close Focus – The close focus is the minimum distance at which the binoculars are able to focus. People interested in viewing insects using their binoculars would be advised to choose a model with a small close focus distance. Models with particularly low close focus include the Opticron Discovery and Traveller ranges, the Swarovski EL and the Kite Caiman binoculars.

Weight – The weight of the binoculars is incredibly important, as it is likely that you will be carrying them around for long periods of time. Higher quality models of comparable specification will tend to be lighter than entry-level models, and those with larger objective lenses will weigh more than those with smaller ones. Binoculars that are particularly lightweight and excellent for travelling include the Opticron Traveller range, the Hawke Optics Nature-Trek and Endurance ranges, and the Nikon Monarch 5 range.

Eye Relief – This is the maximum distance from the eyepiece lens that the eye can be positioned at which the full width of the image is visible without vignetting (darkening of the image around the edges). Longer eye relief is useful for those who wear glasses.

If you have any queries regarding binoculars then our Customer Services team and trained Wildlife Equipment Specialists would be delighted to assist on 01803 865913 or via email at customer.services@nhbs.com.

Recommended Models

Entry Level

Hawke Optics Nature-Trek
One of our most popular models, lightweight with good optical performance

 

 

General Purpose

Opticron Discovery
Phase-coated prisms give optical performance that is a step above entry level, fantastic field of view and close focus

 

Hawke Optics Endurance ED
These affordable binoculars have ED glass to provide crystal clear images, representing great value for money.

 

Travelling

Opticron Traveller BGA Mg
The perfect binoculars for travelling, they have good field of view, great close focus and are amazingly lightweight and compact. For an even more exceptional optical performance try the Traveller ED range.

Mid range

Kite Lynx HD+
These binoculars have an astonishing field of view and exceptional close focus with ED glass for excellent colour reproduction and scratch resistant lens coatings.

 

Nikon Monarch 5
With ED glass for good colour reproduction and dielectric multilayer prism coatings, the Nikon Monarch 5 binoculars provide fantastic optical performance in a lightweight body.

 

Top of the Range

Swarovski EL
The EL binoculars range is hand made in Austria with field flattener lenses, fluoride glass and Swarobright coating to provide an unparalleled optical experience.

 

Banner image features Northern Lapwings (Vanellus vanellus). Photo credit: Tony Hisgett – www.flickr.com