Catching Great Crested Newts with the Dewsbury Box Trap | Guest article by Lucy Bartlett
Posted in:
Amphibians, Great Crested Newt, Ponds, Research, Survey Methods, Surveys and Assessment
Date posted: 30 November 2015
For the last three years I have been working on a project to test the effectiveness of box traps, or more specifically the Dewsbury Box Trap, to survey for and capture great crested newts (Triturus cristatus). Originally an MSc project, it has developed into an interesting and ongoing piece of private research.
The design of the trap (see the video links below) means that it sits at the bottom of the pond, with a large air sack reaching the surface to ensure a supply of oxygen. Once they have entered the traps, which are set in the evening, the amphibians have plenty of space to move around, only having to settle at the bottom when the trap is emptied. There is little danger of overcrowding or overheating and, if deployed correctly, the traps are not at risk of drying out or fully submerging.
Over the three survey seasons (2013 to 2015) I have trapped 557 great crested newts in 14 ponds. The original project, designed with input from Dr Emma Smith (Bristol University) and Lyndon Roberts (Alar Ecology), tested the box trap in a number of different ponds with known great crested newt populations, and at different positions within the ponds. It included a direct comparison with bottle traps, an experiment I have repeated in subsequent years. The results (see the table below) were surprising on two counts: firstly, the much larger number of great crested newts caught by the box trap compared to the traditional method; and secondly, the sex of the captured newts, with the box traps consistently capturing a higher proportion of males. During the biggest catch, we found 30 males and four females in a single trap!
| Trap Type | Total Traps | GCN Males | GCN Females | Total GCNs | GCNs per trap |
|---|---|---|---|---|---|
| Box | 99 | 293 | 125 | 418 | 4.22 |
| Bottle | 85 | 31 | 108 | 139 | 1.63 |
Quick and easy to use, safe for people and animals, and with high numbers of captures, I have found this to be an effective trapping method. The main drawback is the relative cost of the traps. Also, the use of box traps is not currently recognised by Natural England as an acceptable survey method, and is not covered by the CL08 Class Survey Licence (Level 1 or 2), though it is relatively straightforward to get a separate licence following a period of training. This method of trapping has a number of practical applications – for example, clearing a pond (subject to a mitigation licence), and capturing newts for training/educational and conservation purposes including monitoring.
The following videos are of trapping sessions which took place at Folly Farm, Somerset, in May 2015, involving conservation assistants Ella Beeson, Becca Grainger-Wood, Josh Mitchell and Amy Tyrer from the Avon Wildlife Trust, led by Joe McSorley.
Finally … Nick Hargreaves (Ecologist, The Landmark Practice) provides a demonstration of the whole process in a series of stills.
If you would like more information about this project, please contact me via the following email address: enquiries@alar-ecology.co.uk
More information about the Dewsbury Box Trap is available from the NHBS website.
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