NHBS Guide to Dormouse Survey Equipment

Dormice are a distinctive family of rodents, found widely across Eurasia and Africa. The Hazel Dormouse (Muscardinus avellanarius) is a native British species which resides primarily in deciduous woodland. They are protected by EU law because of their rapidly declining numbers – studies suggest they have suffered a 72% population reduction in the last 22 years. Dormice are an important bioindicator as they are particularly sensitive to habitat and population fragmentation, so their presence is an indication of habitat integrity.

To enforce legal protection and ensure the success of conservation projects, current data about the distribution of Hazel Dormice is very important. A variety of survey equipment and methods can be used by licenced dormouse handlers and wildlife enthusiasts.

Nest Boxes

Perhaps the simplest survey technique to determine dormouse presence is searching for the nest box residents. Dormouse nest boxes are largely similar to standard bird boxes, but with the entrance hole facing the tree. Nest boxes can be important conservation tools as they can boost the local dormouse population density and aid re-introduction schemes.

The Standard Dormouse Nest Box is built from FSC softwood and has a removable lid with a wire closure for monitoring. This box can also come with a perspex inner screen allowing  surveyors to check the boxes inhabitants, without the risk of escape or  injury.

The more resilient Heavy Duty Dormouse Box is made from thicker  ¾” FSC marine plywood and is ideal for long-term monitoring projects. 

Dormouse Tubes

Dormouse nest tubes are a cheap, easy and popular method of determining the presence of dormice within a habitat. They can be an effective alternative to using wooden nest boxes.

The tubes consist of a wooden tray and a nesting tube. Dormice make their nests in the tubes and it is these that are used as indicators of their presence in the habitat. Nest tubes can be set up and checked without a licence until the first evidence of dormouse activity is found. After that, only a licensed handler can check them. For attaching to a tree, Hook and Loop Strapping is a more environmentally friendly alternative to plastic cable ties, as they are reusable, reducing plastic waste.

Dormouse Footprint Tunnels

The latest dormouse surveying technique uses footprint tunnels. This technique was created by Suffolk Wildlife Trust with PTES funding and has since been recommended in the CIEEM magazine In Practice in September 2018.

It is a non-invasive survey technique, which does not require a licence as the chance of disturbing dormice is very low. The 40cm tube, houses a wooden platform which contains the charcoal ink and paper on which footprints are left. Compared with nest tube surveys, footprint tunnels can reduce the survey period required and provide an indication of the presence or likely absence of dormice at a site.

Dormouse Nut Hunting

Dormice leave very characteristic marks when they eat Hazel nuts. They gnaw a round hole in the shell leaving a smooth edge with very few teeth marks, unlike mice or voles. Systematic nut searches under Hazel trees are still regarded as one of the best survey techniques, only hand lenses and a keen eye are required.

Accessories and books

Below are some accessories and books that are commonly used for dormouse surveys and monitoring:

Small Mammal Holding Bag
£3.60
Pesola Light-Line Spring Scales
From £35.00

Pesola PTS3000 Electronic Scale

£126

Heavy Duty Extra-Large Polythene Sample Bags
£0.70 per bag

Animal Handling Gloves
£5.69 5.99

LED Telescopic Inspection Mirror
£11.99 

How to Find and Identify Mammals
£11.99

Britain’s Mammals: A field guide to the mammals of Britain and Ireland
£12.99

Continue reading “NHBS Guide to Dormouse Survey Equipment”

Dormouse Nest Tubes – fast, secure placement

How have we improved our dormouse nest tubes?

dormouse tubeWe have just released a new and improved model of the dormouse nest tube. What’s different? Well, we have tried to tackle two of the most frequently encountered problems with setting up dormouse nest tubes. (1) It can be tricky to attach them securely to a branch and (2) once ‘securely attached’ they are prone to slipping. To reduce these issues we have added retaining loops to the base of the nest tube to stop slippage and to enable faster placement.

We also supply 71cm cable ties for fast set-up. If you prefer using garden wire to secure your nest tubes then this method will also be easier using the new loops.

Dormouse survey – best practice

hazel dormouseFor the non- (or new) professionals out there a few quick pointers on best practice for a survey using dormouse nest tubes.

  1. Surveys should not be limited to habitat perceived as ‘optimal’ but should be undertaken in any areas of affected woody habitat (including adjacent areas if the impact of development is likely to extend beyond the site footprint).
  2. Normally at least 50 nest tubes should be placed at roughly 15-20m intervals and these should be left in place (and checked monthly) for the majority of the active season.
  3. In order to have any chance of obtaining a license to carry out work affecting dormouse habitat you must first conduct a survey with a probability of 20 or above of finding dormice if they are present (although please remember that an absence of evidence is not evidence of absence). To calculate the probability score for your survey you add together the scores (Table 1) for the months during which the survey was conducted (for surveys conducted using 50 dormouse nest tubes and following the advice given in points 1 and 2 above).

dormouse survey results

 

 

 

 

 

Taken at face value this means that all dormouse surveys should begin by June at the latest; however, it is possible to start a survey later than this under certain conditions. For example, you can increase survey effort by increasing the number of dormouse nest tubes deployed (if you use 100 tubes you can double the scores in Table 1). Note though that surveys conducted using a large number of tubes for a short period are not good practice and nor are surveys where tubes are crowded together at intervals of less than 15-20m (although 10m intervals may be acceptable in very small sites).

For further details we recommend you consult the latest guidance from Natural England in England or your national licensing authority (e.g. Countryside Council for Wales, Scottish Natural Heritage, etc.).

Dormouse resources:

The Mammal Society

Dormice: A Tale of Two Species jacket imageDormice: A Tale of Two Species
Pat Morris

 

 

 

Living with Dormice jacket imageLiving with Dormice
Sue Eden

 

 

Dormouse survey products:

dormouse nest tubeDormouse nest tubes

 

 

Standard Dormouse BoxDormouse box

 

 

 

 

 

Book of the Week: Dormice

Continuing our selection of the very best titles available through NHBS:

Dormice: A Tale of Two Species

by Pat Morris

What?

Second edition of Morris’s  informative treatment of the natural history, and current conservation and ecological status, of Britain’s two native species of dormouse.

Why?

The dormouse had been particularly under-represented in biological and conservation researchDormice jacket image before Pat Morris, in 1983, began experimenting with designing a more suitable trap than had previously been available. His success led to meetings with other interested researchers and a project began to fully observe the hazel dormouse in its natural habitat.

The success of this project led to Morris and his colleagues being approached to consider the other native species, the edible dormouse – and the two species are treated separately in this volume, being of such different temperament and life-style.

This book, updated with new information for the second edition, is the product of the discoveries made over the years since these studies began, and its detail and comprehensive approach make it invaluable to anyone interested in the state of Britain’s natural history, and dormice in particular. It is written with both the researcher, the ecologist, and the general reader in mind and could do much to encourage amateur interest in these elusive creatures.

Who?

Dr Pat Morris was Senior Lecturer in Zoology at Royal Holloway, University of London until 2002. He has studied various mammals for over 50 years and has published over 80 scientific papers, and is author of The New Hedgehog Book. He has spent 20 years researching both species of native British dormouse.

Available Now from NHBS

Celebrating 60 years and Counting of the Longworth Mammal Trap

The Longworth mammal trap was invented in 1949 and is celebrating over 60 years of service. As the most widely used and respected small mammal trap in use in Europe, it is familiar to many of us. But how well do you actually know it? Read on for some facts on the Longworth trap you may or may not know!

The Longworth mammal trap was invented in 1949 and is celebrating over 60 years of service.  As the most widely used and respected small mammal trap in use in Europe, it is familiar to many of us.  But how well do you actually know it?  Read on for some facts on the Longworth trap you may or may not know!

Why is it called the Longworth trap?

Longworth TrapUnfortunately it’s not because Mr Longworth invented it.  The Longworth trap was invented by Chitty & Kempson (1949).   At the time they were working at the Department for Zoological Field Studies at the University of Oxford.  They arranged commercial production through another Oxford-based organisation, the Longworth Scientific Instrument Co. Ltd, and the trap took the same name.  The Longworth Scientific Instrument Co. was founded in 1943 by another group of Oxford academics.  Personnel from the Department of Anaesthetics formed the company to manufacture technical medical equipment such as the Macintosh Laryngoscope.  As the Longworth trap required similar manufacturing processes, it made sense for the Longworth Co. to manufacture Chitty & Kempson’s trap.  Due to its strong geographical links, you may also have heard the Longworth trap called the Oxford trap, although a prerequisite for this is a long memory, even longer beard and elbow patches!

Are Longworth traps good for sampling shrews?

Longworth trap with shrew holeTraditionally there has been a belief that pitfalls rather than small mammal traps such as the Longworth should be used for catching small shrews (e.g. Williams & Braun, 1983).  However, recent evidence may suggest that this is not always the case (e.g. Anthony et al., 2005).  Every trap design will introduce some type of bias, so the key is to ensure as fair a test as possible.  Comparing two datasets obtained using different trap designs will obviously introduce error.  If you are particularly concerned about small shrews then consider using Longworth traps in tandem with pitfall traps (using drift fences with the pitfalls will generally increase success).  Remember that vegetation type and even trap age may possibly influence trap success.  The fact that Longworth traps are incredibly durable with many still in use after 30 years of service makes them ideal for repeat long term surveys.  And remember, you won’t catch any small shrews with the Longworth trap with optional shrew escape hole!

How do I bait the trap?

The bait smell will initially attract the mammal to the trap so try to handle the bait as little as possible, especially if you’ve got smLongworth trapelly (perfumed or otherwise!) hands.  Shrews and other insectivorous mammals will need invertebrates; try blowfly pupae available from fishing tackle shops.  Otherwise seeds, raisins, barley, oats or even chocolate will do.  By using fruit or vegetables (apples and carrot can work well), you can also provide an essential source of water for the trapped mammal.  The type of bait used is probably of little importance in trap success (Sealander & James, 1958), and by using the same bait in all traps the effect of bait type will be nullified.

Acclimatising mammals to the trap is particularly important, especially when sampling more timid species.  The Longworth is ideal for this as it can be set not to trigger when an animal enters.  Bait the trap in the ‘non-trigger’ setting and leave for several days for this acclimatisation to occur.  But remember, by doing this you may attract other individuals from surrounding areas and inflate population density estimates.

Also remember to provide some bedding in the trap; hay or shredded paper work best.  If using leaves (or indeed anything else), make sure they are dry as damp nest material can chill the animal.  Change the bedding after every capture to ensure a dry clean trap for the next unlucky victim.

Where should I place the trap?

Place the trap in a sheltered secluded location, ideally in thick vegetation, but make sure you can find it again.  A bright marker on the trap can aid location of it but can also make it more conspicuous to the public.  Place the leading edge of the trap flush with the ground to encourage animals to enter.  Ensure the nesting box is at a slight angle to encourage urine to drain away.  When placing the trap, look out for signs of mammal activity (droppings, runs through vegetation, chewed food, etc).  These are unlikely to be in the middle of clearings as small mammals tend to prefer margins, hedges, etc.  Usually multiple traps will be deployed.  By deploying in a grid formation you will get a better idea of population density, whilst straight line deployment is useful for covering a cross section of habitats or following linear features (hedgerows, boundaries, etc).

Is there a cheaper alternative?

Mammal Trip-TrapLongworth traps are expensive and the initial cost of buying the traps can be high.  However, it is worth remembering than Longworth traps will last decades if looked after properly so the cost of the trap over its lifetime is actually quite cheap.  Nevertheless, a cheap alternative is the Mammal Trip-Trap.  This is a simpler trap to the Longworth and designed for occasional use.  It is made from robust plastic rather than the Longworth’s aluminium, but also features a trapping tunnel and nest box.  However, as woodmice have on occasion been known to chew through the aluminium on a Longworth trap, the plastic trip-trap may be severely damaged unless checked very frequently.

Longworth trapWhichever trap you use, remember to check them at least every 12 hours (and even less for shrews as they are particularly prone to mortality in traps).  You also need a licence to trap shrews.  If you have any other queries on the Longworth trap or Trip-Trap then please get in touch.

References

Anthony NM et al. (2005) Comparative effectiveness of Longworth and Sherman live traps. Wildlife Society Bulletin 33: 1018-1026
Chitty D & Kempson (1949) Prebaiting small mammals and a new design of live trap. Ecology 30: 536-542
Sealander JA & James D (1958) Relative efficiency of different small mammal traps. Journal of Mammalogy 39: 215-223
Whittaker JC & Feldhammer (2000) Effectiveness of three types of live trap for Blarina (Insectivora: Soricidiae) and description of new trap design. Mammalia 64: 118-124
Williams DF & Braun SE (1983) Comparison of pitfall and conventional traps for sampling small mammal populations. Journal of Wildlife Management 47: 841-845

Living with Dormice – Now in Stock at NHBS

The dormouse is one of the least seen but most loved of British animals. Dormice have always been portrayed as elusive, rare animals with specialised food requirements found only in large ancient woodlands.

Sue Eden was therefore surprised to find them nesting in the coastal scrub of her new garden. Her many years of ensuing research have led her to the conclusion that the dormouse is in reality a widespread, tough, opportunistic omnivore that appears just as at home in low coastal scrub and conifer plantations.

This fascinating new research, together with many colour photographs, provides an inspiration in the search for this appealing creature.

Living with Dormice is now in stock at NHBS – order your copy today

Also check out our selection of Dormouse Nest Tubes and Dormouse Nest Boxes

Browse other recent British Wildlife titles

Dormouse Nest Tubes New in Stock at NHBS

Dormouse Nest Tubes are now available from NHBS. These nest tubes provide a cheap and easy method of determining the presence of dormice within a habitat, and provide an effective alternative to using a large number of more expensive wooden nest boxes.

The dormouse nest tube consists of two parts – the wooden ‘tray’ and the ‘nesting tube’. The tray, made from 3-ply, fits securely inside the nesting tube (made from plastic tree guard material), with a wooden block sealing the tube at one end. Dormice make nests in these tubes, and it is these nests that are used as indicators of their presence in the habitat.

We supply the nest tubes as singles, and at discounted prices for 10’s and 100’s.

Find out more about dormice in Natural England’s Dormouse Conservation Handbook and the Mammal Society’s The Dormouse.

Also check out our sturdy wooden Dormouse Nest Box – ideal for long-term dormouse accomodation.

Browse Nest Boxes & Habitats for birds and mammals

The Vincent Wildlife Trust and NHBS

We are pleased to announce that the Vincent Wildlife Trust has appointed NHBS the official distributor for their publications, including the new and bestselling Lesser Horseshoe Bat Conservation Handbook.

177164

Other Vincent Wildlife Trust publications distributed by NHBS include:

The Bats of Britain and Ireland (Bestseller)

The Polecat Survey of Britain 2004-2006 (New for 2008)

Distribution and Status of the Polecat in Britain in the 1990s

The Distribution of the Hazel Dormouse in Wales

The Vincent Wildlife Trust Review of 1997-2000

The Water Vole and Mink Survey of Britain 1996-1998

The Water Vole in Britain, 1989-1990

For more than 25 years The Vincent Wildlife Trust has been supporting wildlife conservation through research, surveys and the establishment and management of reserves for British mammals. Since 1996 the VWT has concentrated its resources on bat conservation, and particularly on the protection and enhancement of roosts for rare bats. It has also maintained its involvement with conservation-led research and survey work on pine martens, polecats, water voles and dormice.

See a complete listing of Vincent Wildlife Trust publications

Click here to find out more about the Vincent Wildlife Trust