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Adder survey queries

Printed From: Reptiles and Amphibians of the UK
Category: Conservation
Forum Name: Method & Management
Forum Description: Discuss habitat management, survey methods etc.
Printed Date: 21 Oct 2020 at 8:21am
Software Version: Web Wiz Forums 11.06 -

Topic: Adder survey queries
Posted By: john1984
Subject: Adder survey queries
Date Posted: 21 Feb 2014 at 7:26pm
Hi all,

I'm new here and hoping to get some advice and suggestions from you.

I'm considering doing a reptile survey on a designated nature reserve in Scotland, in a voluntary capacity.  This site is a couple of wooded stream valleys with areas of grassland and bracken, including some nice south-facing banks.  Adders are known to occur on the site, slow worms are unlikely but possible, and I imagine there may well be common/viviparous lizards too.

The site is about 60ha, and from my understanding, to do a survey enabling a population estimate would require a colossal amount of ACOs, which I don't have, can't afford and would be unable to place and check!

I'm likely to be able to do four visits (possibly more) in suitable conditions from late March to June, probably including ACOs and a transect.  To cover the entire reserve is about 6 miles so isn't possible for a transect to cover the whole reserve.

I'm just wondering, in your experience, what the best way to go about this survey would be?  Essentially it's not going to provide a population estimate, but will give details of distribution to an extent, and will update records for the site.  I am currently early in the 'thinking' process for this, but am thinking probably a walked transect of about 2 miles, with ACO/refugia placed in apparently good habitat (i.e. the south facing banks and slopes).  Some of these slopes are steep and therefore it would be difficult to walk them without stomping a bit (and thus disturbing basking reptiles).

Any thoughts appreciated.



Posted By: GemmaJF
Date Posted: 21 Feb 2014 at 7:43pm
Unfortunately John adder are not always that quick to use ACO - they need to be down a long time for them to intercept them and use them. 

Most adder survey I undertake involves visual survey. The usual techniques involve identification and monitoring of hibernacula before the animals disperse. (Which could be undertaken immediately on good days). ACO are somewhat more effective in summer feeding grounds but this is not relevant to your survey timing.

The ACO will be useful for slow worm and common lizards of course and **may** attract adder in time.

I think you have the basis for the survey of targeting apparently suitable habitat with smaller numbers of ACO to get a snap shot, filling in with visual observations. Four visits is very few, at some sites I have undertaken over 18 visits to detect adder that were know to be there!

Really with your current plan at best you would confirm continued presence, not enough survey effort to draw any conclusions about distribution, population estimate or absence particularly of adder in my opinion.

So perhaps if resources are tight regarding ACO deployment, not such a problem regarding adder, but more visits might be worth considering.

Which ACO material are you planning to use?

Posted By: Chris Monk
Date Posted: 21 Feb 2014 at 10:35pm
The Peak Park put some corrugated tin ACOs out in 1994 in areas where staff had seen adders and visited them every Saturday & Sunday from spring to autumn in 1994 & 1995 to count the adders. They saw plenty of adders but not a single one was ever found under an ACO in those 2 years. Some of those ACOs are still out there now and in our surveys since 2005 we've never seen any adders under them, just one had an adder a few times one year basking on the top where some old bracken had fallen over the edge.

Best to look for likely adder basking areas depending on topography, aspect and vegetation structure and walk round them on days with suitable weather conditions this spring (March / April) and if you find an adder or two basking, record where it is and revisit the site. Numbers can vary over a short time let alone from day to day and finding good spring basking sites is important as they are likely to be close to the hibernation locations which need protecting from adverse management.


Derbyshire Amphibian & Reptile Group

Posted By: PondDragon
Date Posted: 21 Feb 2014 at 11:21pm
It's worth trying to get photos of any adders you do spot, which is helpful for recognising particular individuals on future visits. Top of the head and neck is best for ID, although left/right head shots are also useful.

Posted By: john1984
Date Posted: 23 Feb 2014 at 4:58pm
Thanks all.  It's interesting about ACO as I've heard from quite a few people that adders rarely use them, but from other sites where they are regularly used.  I guess it varies, although it is clear that they are far less useful than for slow worms for example.

As the reserve is quite large, and there is no actual need for a population assessment, I might simply chose some walked transects and do these as many times as I can, in order to at least see which areas are being used by adders (or rather, areas being used where I am lucky enough to see them Confused)

Also, and forgive me if this is a silly question, but what is the best way to observe/ survey adders on steep-ish banks of grassland?  I'll have binoculars with me, but imagine this is of limited use as the snakes are so inconspicuous most of the time.  It would be difficult to walk through some areas without disturbing the animals which is a bit silly as it doesn't help the survey if the snakes have scarpered, and it also causes disturbance!


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