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

Night Vision Scopes at NHBS

Night vision scopes work by collecting available light, normally from the moon and stars, and amplifying this to generate a meaningful image. The main component of any scope is the Image Intensifier, a vacuum tube that differs in design depending on the generation of scope (more info on generations later!). The image intensifier collects particles of light (photons) and focuses them onto a photocathode. The photocathode absorbs these photons and converts them to electrons, which are subsequently amplified and projected onto a green phosphor screen at the rear of the tube. To do this the photocathode needs a power supply, normally from commercially available batteries.

When the electrons hit the phosphor screen, the screen emits visible green light that the user can see. Therefore, you do not look through a night vision scope, but rather look at an amplified electronic image on a phosphor screen. As the phosphor screen emits light in exactly the same pattern and intensity as the light collected by the objective lens, the screen image corresponds to the actual scene in front of the scope. The phosphor screen is coloured green because the human eye can differentiate more shades of green than any other phosphor colour.

There is a bewildering array of night vision scopes available for amateur, commercial and military purposes. NHBS has selected a range of scopes and accessories that match the needs of amateur and commercial users so we hope there is no chance you are going to get shot at whilst using them! All our scopes have been tried and tested by wildlife and land management professionals and so provide versatile and durable solutions to seeing at night. However, even amongst our range there are subtle differences that make some scopes more suitable than others for certain uses. Below is a list of criteria to consider when making your choice. If you are still unsure, then please contact us as we would be happy to provide further advice.

For more on this blog, see the NHBS Quick Guide: Night Vision Scopes

New Titles in Entomology – including Moths of Europe, Volume 2

Moths of Europe, Volume 2: Geometrid MothsSome great new insect titles are now available at NHBS, most significantly Moths of Europe, Volume 2: Geometrid Moths which is now in stock at NHBS – order your copy today.

Moths of Europe, Volume 2: Geometrid Moths deals with more than 1000 species of Lepidoptera traditionally grouped together as geometers and classified in the Geometridae family (plus a single species from the Uraniidae): Illustrations are displayed in the form of 158 colour plates showing 1116 species in 2800 photos. Four new genera, seven species and 17 subspecies are described. Moths of Europe, Volume 1 is also available for purchase.

Other newly published titles include Insect Species Conservation and Sharpshooter Leafhoppers.

Insect Species ConservationSharpshooter Leafhoppers

 

 

 

 

 

 

 

 

Browse more New Entomology Titles

Also browse our recent Entomology Bestsellers and Equipment Bestsellers

NHBS Quick Guide – Butterfly Nets

Take a closer look at the beautiful butterflies of your region with one of the wide variety of butterfly nets offered by NHBS.

From the portable Crushable Pocket Butterfly Net to the heavy-duty Large Butterfly Net, we offer a butterfly net for every need (and for every age – check out the Children’s Butterfly Net). With these nets, you can safely capture and examine butterflies and other insects, then release them back into the wild.

We list over 1500 lepidoptera books at NHBS, including these Butterfly Bestsellers.

Large Butterfly Net

Large Butterfly NetThis complete butterfly net set includes a 47cm (18 inch) diameter frame, a deep net bag, and a 60cm extension handle. The extension handle can be removed from the frame for transport, or to use the net frame/bag without the extension where extra length is not required. The net bag is constructed from soft Terylene material that will minimise damage to insect wings and stand up well to UV degradation. Available in both white and black netting. This large, strong portable net is also suitable for catching bats.

Standard Butterfly Net

Standard Butterfly Net
This complete butterfly net set includes a 37cm (14 inch) diameter frame, a deep net bag, and a 60cm extension handle. The extension handle can be removed from the frame for transport, or to use the net frame/bag without the extension where extra length is not required. The net bag is constructed from soft Terylene material that will minimise damage to insect wings and stand up well to UV degradation. Available in both white and black netting.

Small (Children’s) Butterfly Net

Children's Butterfly NetA lightweight butterfly net well suited for children and educational use. The wooden handle provides good grip and reach. The net bag is constructed from soft Terylene material that will minimise damage to insect wings and stand up well to UV degradation.

Butterfly Net and Ultra-Light Frame

Butterfly Net & Ultra-Light FrameThe net handle is black moulded plastic on a black plastic coated aluminium frame. There is a hook on elastic in the end of the handle to hang the net from a belt or rucksack. The net is attached by velcro and can be easily removed to wash. It is very light fitting a “spoon shaped” frame 38 x 28 cms. and 50 cms deep. The net material is olive green (camouflage colour) mosquito size mesh.

Lightweight Folding Butterfly Net (Small)

Lightweight Folding Butterfly Net (Small)tThe Lightweight Folding Butterfly Net can be used with its telescopic handle half extended for close sweeps, and fully extended to lengthen your reach to over 1m. The net is highly portable and folds down into its own bag for carrying (it’s small enough to fit into a typical rucksack). The frame is robust and designed to withstand years of field use.

Crushable Pocket Butterfly Net

Crushable Pocket Butterfly NetA butterfly net with a spring steel frame which twists up, allowing the net to be collapsed and folded to a pocket size (instructions provided). The net is supplied with a short brass handle for general use; this can quickly be extended by inserting a stick or a piece of wood to into the handle.

Check out our full range of Butterfly Nets

Browse our wide selection of butterfly and entomology titles in Arthropods and Insects

Browse our extended range of Wildlife Equipment

New Bird Conservation Books from NHBS

A Best Practice Guide for Wild Bird Monitoring Schemes is essential reading for all those involved in bird counts, conducting surveys, analysing monitoring data and managing results. This key resource outlines the general principles of good survey design and best practices for sampling, field methods, and data analysis. Contributors include the RSPB, EBCC, CSO, BirdLife International, and Statistics Netherlands.

175898175898

 

 

 

 

 

 

 

 

 

Another new bird monitoring title is Bird Ringing: The Concise Guide, published by the BTO. This book is an ideal training tool for ringers, explaining how and why we ring birds. It contains numerous examples of how ringing has contributed to conservation science and research, and how ringing helps us understand population changes by providing information on survival and recruitment.

For more new titles and related equipment, browse New Bird Conservation Titles and Equipment

We stock a wide range of fieldwork equipment including bird weighing scales, ringing pliers, GPS units, and nest boxes and camera kits. To see our full selection, browse Wildlife Equipment

Browse our full range of Bird Conservation, Care, and Monitoring titles

Don’t miss the great deals on ornithology titles in our annual Backlist Bargains sale (ends 31/03/2009).

Browse our full range of birding titles in Ornithology

Top Titles of 2008

Here are the most popular books of 2008 at NHBS: the Top 10 overall and the Top 10 in each of our major subject areas. You’ll find an eclectic mix of geographic and taxonomic interest, with books from publishers all over the world. We’ve also included bestselling wildlife equipment from our new range of field kit.

Enjoy browsing, and please feel free to add your own recommendations for this year’s Top Titles at the bottom of this post.

Top 10
1. Dragonflies
2. Climatic Atlas of European Breeding Birds
3. Sedges of the British Isles
4. Mammals of the British Isles
5. Life in Cold Blood – DVD
6. Mabberley’s Plant-Book
7. Which Bat Is It?
8. RES Handbook Volume 4 Part 2: The Carabidae
9. Wild China – DVD
10. Guia de Campo: Birds of Amazonian Brazil

Top Birding
1. Grouse
2. Climatic Atlas of European Breeding Birds
3. Handbook of the Birds of the World. Volume 13: Penduline Tits to Shrikes
4. All the Birds of Brazil
5. Ornithologist’s Dictionary
6. Owls of the World
7. Collins Bird Guide
8. Frontiers in Birding
9. The Migration Ecology of Birds
10. Guia de Campo: Birds of Amazonian Brazil

Top Zoology
1. Dragonflies
2. Mammals of the British Isles
3. Which Bat Is It?
4. RES Handbook Volume 4 Part 2: The Carabidae
5. Tiger: Spy in the Jungle – DVD
6. Guide to the Mammals of China
7. Primates of the World
8. Wolf
9. Field Guide to the Mammals of South East Asia
10. Guide to British Bats

Top Equipment
1. Opticron Hand lens, 18mm, 20x magnification
2. WeatherWriter A4 Portrait
3. Vista Organiser
4. Schwegler 1B Nest Box
5. Schwegler 2F Bat Box
6. Batbox Baton Bat Detector
7. Garmin GPS Map60Cx
8. 125W MV Robinson Moth Trap
9. Professional Hand Net (Standard 250mm Wide Frame)
10. Pooter

Top Ecology and Conservation
1. Primer of Ecological Statistics
2. Behavioural Ecology
3. Introduction to Molecular Ecology
4. Analysis of Ecological Communities
5. Management Planning for Nature Conservation
6. Sustaining Life
7. Handbook of Biodiversity Methods
8. Atlas of Endangered Species
9. Conservation and Sustainable Use
10. Scaling Biodiversity

Top Botany
1. Sedges of the British Isles
2. Mabberley’s Plant-Book
3. The Wild Flower Key
4. New Cactus Lexicon, Volumes I and II
5. Wild Flowers of the Mediterranean
6. Secret Lives of Garden Wildlife
7. Lichens: An Illustrated Guide to the British and Irish Species
8. Flowering Plant Families of the World
9. British Orchids
10. BRYOATT: Attributes of British and Irish Mosses, Liverworts and Hornworts

Top Natural History
1. Wildlife Photographer of the Year, Portfolio Eighteen
2. Attenborough in Paradise and Other Personal Voyages – DVD
3. Birds and Light: The Art of Lars Jonsson
4. Lars Jonsson’s Birds
5. Seventy Great Mysteries of the Natural World
6. Lost Worlds of the Guiana Highlands
7. Guide to Garden Wildlife
8. Earth: The Power of the Planet – DVD
9. Vietnam: A Natural History
10. The Deep

Top Data Analysis and Modelling
1. Describing Species
2. OU Project Guide
3. Statistics for Terrified Biologists
4. Ecological Census Techniques
5. The R Book
6. Experimental Design and Data Analysis for Biologists
7. Spatial Analysis
8. Choosing and Using Statistics
9. Modelling for Field Biologists
10. Quantitative Methods for Conservation Biology

Don’t see your favourite title of 2008 here? Add your own recommendations for Top Titles at the bottom of this post.

To find a particular title, browse our full range of over 100,000 wildlife, science and conservation titles.

Bestselling Wildlife Equipment at the Birdfair

The equipment bestsellers at this year’s Birdfair were small items for entomology:

Bug Box Magnifying Pot – great for freshwater sampling, examining insects and other invertebrates.
Bug Box Magnifying Jar

Entomological Collecting Pots – for holding small invertebrates for examination, they also fit our Pooter so you can swap pots as you collect things. Sold as singles, or in packs of 5.

Entomological Collecting Pots

Pooter – for collecting small arthropods for identification and examination. An entomology essential!
Pooter