Snakes, Coroline, onduline and I

Gemma, I found a slow-worm under a discarded chopping
board once. I wonder what they?re trying to tell us!?

Mark, try getting your tin from your local scrap metal
yard. Use a more homespun, word of mouth, company such as
you might find in a Parish magazine, The Yellow pages
etc. Alternatively if you know, or have friends who know,
farmers make contact with them. Farmers often have
(roofing) materials knocking about and they frequently
wish to get rid of them. As I'm sure you know, tin with
an aged character seems to perform better anyhow, so you
end up paying much less and getting a better working
product.

Failing those try your local cookware store. Pots and
pans could well be the materials for 2011.

The methodology for carrying out surveys to accompany
planning applications or to seek similar permissions
should always include visual surveys. Whether these
searches are carried out or not, or indeed successful, is
another matter. It would depend, I think, on the
individual surveyor's experience, skill and commitment to
the project. It would certainly appear in the methodology
section of their report, or you would expect it to.
Rob

Scale wrote: Why no Slow-worm's mark, any theories? What's the habitat like? Their absence must be unusual for a site supporting the 3 other species, no?

I have no idea why there are no slow-worms at this site. Maybe they never migrated there or couldn't migrate there?

The habitat is heathland in south Wales

herpetologic2 wrote: Also the ACO density is massive yet you have very low numbers of animals?

Yea I was hoping for a lot more animals but they didn't turn up. There were large numbers of grass snakes found through visual encounter survey only 400m away.

It has already been discussed in this thread the importance of refugia placement and by using Reading's method I have to put a particular array in a particular place thus many of the refugia are not in what I class as a prime location. That may well be one of the issues but I couldn't test my theories without constructing the experiment this way. I hope to have some interesting results once I have analysed my data, which I shall post asap.

 

Where do you guys buy metal sheets from out of interest?

How many consultancies do visual encounter surveys as well as refugia surveys (when determining presence and when catching reptiles) ?

There are a great deal of factors involved in this discussion and I think no simple answer or single best material though factors like handling and even appearance become important in large consultancy style mitigations.


My data shows for example best performance for Onduline is on fairly uniform grassland sites. A habitat we have often encounter on development sites.

Adder use refugia, but nearly all my encounters of adult adder under or on refugia are in the summer feeding grounds. .. a pointer that adult adder only tend use refugia for long periods whilst actively feeding. The pattern is similar for adult grass snakes only in this case they are either digesting or sloughing.


In all I totally agree we should be flexible and open minded. If I was forced to use one material, it would be Onduline. I too can get results with simple visual survey for adder, it still remains my main technique for adder due to their reluctance near hibernation areas for example to even use refugia. An hours visual survey will often get a result where refugia survey produces nothing for months.

The biggest factor though as Jon has stated is placement. I've been out on one of Jon's sites and clearly remember thinking when I saw the refugia 'that's exactly where I would have put them'. Sounds trivial but  it compares to being out with many claimed reptile consultants who randomly place refugia with little hope of any of them producing animals as they simply lack a feel for the work. You either see the right places or you don't. It's simply experience of knowing where you would look visually and as many of these people have never perfected visual survey they have no more idea than a member of the public as to where refugia should be placed.

For slow worm btw we should be using car doors and concrete slabs and old saucepans.. I remember lifting a car door at the Mabledon Hospital site and what I would guestimate at 40 slow worms were either in or under it. On the same site I lifted a concrete slab covering some of the underground drainage system that remained on the site, and there were 20 slow worms of all lifestages. These were not officially recorded sightings but when I check them against the tin felt survey I undertook at the site  a couple of years earlier we only had a handful of slow worm show during the survey and most of these were under carpet tiles left over from a previous survey. The saucepan was on a site that produced no slow worm at all using the usual refugia materials, but under the saucepan we found a huge adult male.

Jon,
Is that from a single peak count or are you using combined
biometrics and suggesting a similar high rate of non-
detection over time. Surely a well recorded site (such as
yours) would lean more towards a 10% detection rate, if not
much greater.

Also I'm not sure how GCN capture returns can inform Slow-
worm population densities, taking into account that the two
species are so distantly unrelated. I'm not saying it is
wrong by any means but can you explain?

Hi Jon,
Speaking of Slow-worms, I often see reference to a 5-10%
detection rate of populations in survey reports. Is this
based on an ACO density of 10 per ha/ and a defined number
of visits? Most reports i have seen using this figure also
use an indeterminate number of ACO's (generally far
exceeding the often impractical recommended Froglife
density for small sites)and a wide variation in survey
effort. Has it just been shown that a 5-10% variation
covers the broadest range of survey standards? I am often
perplexed by its loose application.
Cheers