This practical session was arranged by Oxford Brookes University, in partnership with Turnstone Ecology who delivered the content. It was based at the Science Oxford Centre and involved an evening session, followed by a morning session. A presentation was delivered covering some ID features of Great Crested Newts and the methods used for surveying, before leading on to practical work surveying for newts.

Turnstone Ecology

Newt surveying

21/22 March 2024

Great crested newts (GCN) have protection under both British law (Wildlife & Countryside Act 1981) and European law (European Habitats Directive 1994); making it illegal to kill, capture, injure or disturb them; damage or destroy habitat; or possess, sell or trade them (Turnstone Ecology, 2024). Finding presence of CGN will afford the pond some protection and may benefit other species too.

There are several survey methods that can be used:

Habitat Suitability Index (HSI):

This measures the suitability of the habitat for hosting newts, indicates if a pond is likely to support CGN.

Environmental DNA (eDNA):

20 water samples are taken from around the pond and mixed. 6 samples are then taken and sent to a laboratory that uses PCR to amplify the DNA and compare it against an existing dataset to determine the presence of GCN. This survey should be done over the newt breeding season (April – May – June), outside of this time and the results will not be considered valid for planning applications.

Refuge searching:

A terrestrial search for where newts may be found e.g. under logs, paving slabs rocks. Care must be taken when looking under a refuge to ensure any animals are not harmed (put it back carefully!)

Egg searching:

This allows you to detect the presence of newts and determine whether it is a breeding pond. Newts will lay their eggs and fold them in vegetation, so this involves checking for folded leaves and gently opening them to identify any eggs. Once one has been found it is then OK to stop, as you will now know it is a breeding pond and no further searching is needed. Smooth and Palmate newt eggs are grey/beige and smaller than GCN eggs, which are white and larger.

Netting:

Not as reliable a method as the other ‘traditional’ methods of egg searching, torching or bottle trapping. It can cause disturbance to the pond, if there is lots of vegetation it can be hard to do and you run the risk of damage larvae.

Torching:

Depending on the species of newt you are surveying for, the ideal survey time may vary. For GCN it is typically 60-180 minutes after sunset. By walking slowly around the pond and scanning every few meters, you can detect the presence of newts – although this is dependent on temperature. Too cold and you won’t see any.

Bottle trapping:

This is a very effective method of detecting newts but does carry a higher risk of causing harm to species. The trap consists of a plastic bottle cut in 2, with the top part then inverted and placed inside the bottom part. A cane is then inserted through holes across the bottle (at an angle). When the bottle is submerged under the water it must have an air pocket at the top as otherwise the newts may suffocate. It is important to note that as warm water holds less oxygen this risk increases in hot weather. This is why it is so important to set up traps in the evening and then collect the next morning. Traps must be counted out and counted in to avoid the risk of leaving one behind. If any are left in the pond by mistake it will result in dead newts. Additionally, as these traps are so efficient, if it is known that there are water shrews in the pond they must not be used. If they are caught in a bottle trap it nearly always leads to their death.

Newt surveying overview

After the presentation I walked and performed a refuge search. Under a paving slab that was covering a pipe (access to electrical conduit) there were a number of smooth newts that had fallen in the pipe and become trapped.

Activity

Next was the setting of bottle traps. As mentioned before, these were counted out, so it was known how many were going into the pond. Using the canes to insert into the pond (no good for lined ponds!), these were placed every few meters around the edge of the pond. I made sure that there was an air pocket in each as it was submerged, although it took a little while to get the hang of judging how big a pocket it was going to be. There were so many newts in this pond that even before we had finished setting them all, the bottle traps were capturing them! See photo below that shows a newt investigating the trap.

Refuge search

Setting bottle traps

Newts found under a paving slab covering a pipe to an electrical conduit.

Bottle trap set, with newt close by.

Bottle trap set.

Egg search

Next, we searched for folded vegetation to see if we could see any eggs. One of our group spotted a folded leaf, in which was an egg! It was white in colour and of the right size for a GCN egg.

Great crested newt egg, in fold of leaf (circled).

Torching

The time was now right for torching. We walked around the pond shining the torch to see newts. This was possible as the pond was not turbid, so the water was clear enough to see them, before the light disturbed them and they hid. I was impressed at how easily/quickly our guide/instructor (Tristan Evans, Director/Principal Consultant, Turnstone Ecology) was able to identify the species and sex of the newts we spotted. There were quite a number, although I wasn't quick enough to capture it very well on camera!

Torching for newts.

Retrieving bottle traps

The next morning, we returned to collect the bottle traps. I took out the traps and placed the newts into trays so that they could be identified and counted. There were quite a few traps, and with the bamboo canes were not always easy to spot in amongst the vegetation. I could see how if you hadn’t counted them in you may easily overlook one.

The number of newts was incredible, with nearly all the bottles containing newts. I was able to practice holding the newts (see photo below of a male smooth newt in my, gloved, hand). This could be helpful in identifying to look at the underside of the newt.

Male smooth newt in my hand.

A bottle trap full of newts!

Me with a bottle trap (Photo credit: Charlotte Grant)

It also provided practice of identification, between GCN and smooth newts (there were no palmate newts here); as well as the differences between male and females. Put next to each other the GCN were typically much larger than the smooth (although this on its own can’t be used as a diagnostic).

• Male GCN had a jagged crest that goes from their head to tip of the tail BUT it dips at the base of the tail (this is during the breeding season). They also have a tail stripe.

• Male smooth newts have an undulating crest BUT it runs from head to tip of tail and doesn’t dip. The underside is yellow and spotted.

• Female GCN don’t have the crest or tail stripe, but they have a yellow/orange stripe on the underside of the tail.

• Female smooth newts have a speckled underside (note how they have speckles under the chin, compared with palmate newts which don’t have speckles under the chin).

It was interesting to see how when out of the water their crests are not as conspicuous.

Gallery

Select from the gallery of additional photos below to view full size image.

Reflection

I really enjoyed this session and it gave me some practical understanding of the traditional survey techniques. I have taken on board a key message of counting out bottle traps and counting them back in, as the last thing you’d want to do is to leave one out! I was told that this site was very unusual in the high numbers of newts that were present, and that I would never survey a site with so many again! It was good to see the differences between the great crested newts and smooth newts, although it would have been nice to see a palmate newt to compare! I recall a previous amphibian survey session I have attended, many years ago, where I was able to compare smooth and palmate newts, but this is something I would very much like to revisit.

In terms of identification, as well as the notes provided by Turnstone Ecology, I find that the FSC ‘Guide to the reptiles and amphibians of Britain and Ireland’ (Roberts and Froglife, 1999) useful as it has decent images that show the key characters.

Other useful resources include the ‘Great Crested Newt Mitigation Guidelines’ (English Nature, 2001) and ‘Great Crested Newt Conservation Handbook’ (Langton, Beckett and Foster, 2001).

References

English Nature (2001) Great Crested Newt Mitigation Guidelines. Peterborough: English Nature.

Langton, T., Beckett, C. and Foster, J. (2001) Great Crested Newt Conservation Handbook. Froglife.

Roberts, P. and Froglife (1999) Guide to the Reptiles and Amphibians of Britain and Ireland. Field Studies Council (FSC). Field Studies Council Fold-out Guides.

Turnstone Ecology (2024) Great Crested Newt Ecology & ID [Presentation]. Science Oxford Centre. 21 March.