RAUK - Archived Forum - Grass snake surveying

Dear all

I'm new to this forum but hope that someone will be able to help me out.

I have a number of sites under my management which are owned by BAA Heathrow Ltd.  Two of these sites are closed access, situated around balancing ponds and support good numbers of grass snakes (with good weather, sightings are almost guaranteed).

I have identified Natrix natrix as an indicator for certain aspects of my management of these sites.  Therefore I wish to carry out formal surveys.  Currently I conduct a standard transect along which I note reptile species seen and numbers.  However I am keen to determine more strictly our population size through capture-mark-recapture and am seeking adivice on the best way to do this with minimal disturbance. 

I am aware of techniques for individual recognition such as belly patterns and scale clipping but in reality have no experience or idea of how easy this will be.  I do have experience of handling snakes (allbeit those from tropical Malaysia) but have not caught nor attempeted to catch UK snakes.  How regularly should surveying occur and what sort of impact would handling have on the population?  The site is not massive and fairly isolated (although there is a border with a river corridor).

Well, I hope that this is enough info, I look forward to any adivce or tips that may be thrown my way!

Thanks

need an assistant? :)

good idea may be to get hold of the Herpetofauna workers manual JNCC. excellent bit of info!

Rhys,

I've been surveying the Grass Snake population in an area of Epping Forest for fifteen years. It is possible to get a fairly accurate idea of 'your' established residents as well as the newcomers, not by clipping scales etc, but by photographic logging of the snakes profiles. We are lucky in UK in that the Grass Snake has individual facial markings, collar size and block patterns on the neck.

The best time to start is mid march, early april. Once you have logged as many as you can locate in the first year, it will quickly become apparent to you which ones you have caught before (they can be easily identified by photgraphic log once you're familiar with them).

I'm not familiar with the topography of ponds/lakes around Heathrow, (though I've done quite a bit of fishing over that way), but, if the ponds form a chain or have many other lakes/ponds adjoining, you may find it difficult to track the Grass Snakes which in any case will take at least five years before you begin to get the picture.

I'd quite happily post to the site, or email you, examples of how the system has worked for me and it has allowed me to keep a log of events such as mating, egg laying sites, hibernaculum, migration (but not nearly as much migration takes place as I'd been led to believe from books such as Deryk Frazer's on reptiles in Britain) and in what locations they may be found from season to season.

Let me know if you wish any assistance and I'd be happy to oblige.

Cheers

Robert

Thanks for the tips!

Rhys

Rhys,

just checking to make sure that you received my email and attchment ok. Let me know if you need it sent again.

Cheers. Robert

Robert

I got the email fine, thanks very much for the help.

Rhys

Robert,

Ok - ID02 and ID23; ID03 and ID24; ID31 and ID12.

I think!

I see what you mean though, once you look a little closer the markings are quite different.

Rhys, thanks for taking the time to prove it!!! You got them all correct. wasn't that hard really eh? Anyway, re; your comments on my capture techniques. Will not be doing that much 'capturing' until October when the snakes start to retrun to the hibernaculum sites.

I've had an egg laying site under scrutiny for a litle while and if theres any action I'll email you at short notice (or text maybe) and maybe we can start by photo Id ing this years neonates.

Let me know when is best time for me to come over to the heathrow site.

Cheers

Robert

 Tony

I know that grass snakes are also found at Harmondsworth Moor (BA Waterside Offices - just off the A4 near to the M25) so they are certainly fairly common in the wider area as a whole.  However, much of the land around Heathrow airport is fragmented sufficiently enough to present significant dispersal barriers.

The sewage farm sounds interesting(!) was it an actual airport site or just in the Heathrow area?  Of course it is possible that these sites still exist just under different names.

Rhys

Tony

Perry oaks is now the building site which will be the new Terminal 5 and the replacement water works is actually a site of mine. I am required to conduct bird surveys here (principally due to the location of the site under the flight path) but the site would no longer be suitable for grass snake.  I have seen little ringed plover there however, which were a nice sight, even if only briefly.

Perry oaks was subjected to a major conservation project which entailed moving an entire wet grassland (which supported water avens) to a new location.  This site has survived the whole process remarkably well and no doubt would present excellent snake habitat given some initiatives to provide egg-laying and hibernation habitats.  The only drawback is that open water is generally considered a no-no as planes and birds dont tend to mix well.  This site is due to come under my care in the not so distant future.

Rhys

Sorry if i've put this in the wrong place but my daughter found this one in our garden this evening, released him/her back to exactly where it was found immediately after taking these photos

Next photo shows it in a 4L ice cream tub to give you an idea of size

If you're interested the rest of the photos I took can be found on this link to my website http://www.ruths-reptiles.co.uk/Grass%20snake.htm

Ruth

Ruth, were these photos of the same snake???? The first looks like an adult female and the second looks like a juvenile. Are you sure you didn't catch two by mistake!

Robert

Ruth, were these photos of the same snake???? The first looks like an adult female and the second looks like a juvenile. Are you sure you didn't catch two by mistake!

Robert

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Absolutely certain it's the same snake, we originally put it into the blue bucket but didn't think the photo's would come out very well due to the colour so transferred him/her into the ice-cream tub, took a few more photos and then released it.

Ruth