Snakes, Coroline, onduline and I

P.S.
Gemma, I noticed that my user name appears as 'Scale' and
not 'Scales' as intended. Is there a way of changing this?
Scale just sounds plain out creepy!

Looks like it is only grass snakes that prefer Coroline and
Adders it seems do not prefer felt.

In what habitat were these arrays Mark?

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

J

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   

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?

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.