Hi all,

I would like to monitor the grass snake population in the garden. We have now at least two cohorts of young snakes, and would be really interested to monitor growth rates and also study how long they stay around before dispersal.

I'm looking at individual ID, measuring weight, measuring length - and recording anything that you guys think would be worth keeping a record of.

I'm a little reserved as this will require a fair bit of handling. What do people suggest. Is tubing OK with such tiny animals? I'm quite use to catching the things but all the extra handling over a period of time to get measurements and ID photographs is a little off-putting. Advice please!

Just to add, I'm currently favouring collecting them up in a bucket, cooling them down for a bit in the shade and dropping them in a squish box, any thoughts welcome

Gemma,

not sure there would be much value in photos as the collars and scales will warp and change as they grow.

Why not build an enclosure for a while and really get some growth records going? That way, you could track the difference in growth rates between males and females.

Just a thought.

Rob

Rob for ID I was going to photo the first 20 ventral scales, this is becoming a popular technique for Nn as the chequer pattern is unique for each animal - I'm not sure though if this can be applied from neo to adult. Couldn't enclose them I'm afraid though, I couldn't bear it as the wildlife garden is there for all to come and go freely.

Al, good point, not much point trying to study residency if I scare them all away, really what I need is a non-intrusive way to photograph the first 20 ventral scales... more pondering required

I must do something though, I have for the first time in my life a study site that won't get mowed, grazed or bulldozed. It might be tiny but what a sample point, a grass snake nursery just outside the backdoor 

so many views of this thread so few comments??

Anyway started the project today with my first slough collected and first capture of a juvenile. Squish box technique worked perfectly, very easy, very little handling involved. Was unlucky that I missed a neo under the same felt, but I'm sure you have all been there with one in the hand and the possible option of losing it if you go for the other.

Once in the bucket with some grass and left for a bit this small snake became very placid as they do after the intitial shock of being caught.

Easily encouraged it to sit in the squish box that needed no more than the foam placing lightly inside to secure the animal for an ID shot. That's all I need for now, I think I can estimate SV from the photo and have enough to recognise the animal. I even got a slough it had left behind under the felt. So day one is looking good

Markers above are 1cm spacing to give an idea of scale.

PS Thanks due to Brett Lewis who first posted regarding squish boxes for snakes. I had never thought of using them for smaller snakes. Have to say it was the least stressful ID I think I've ever done and number 0001 was soon back under the felt where it belongs. Excellent.

Here's an example of the quality and clarity you can achieve with a scanner....

This photo was taken to illustrate necrotic/ulcerative dermatitis in Thamnophis sirtalis.

Fantastic image easy to make out every ventral scale, was the dermatitis a result of too damp an environment or is there another cause?

Just done a couple of dry runs with a bic pen in the squish box, looks good, I'll post up an example of a scanned grassy when I get the next one

GemmaJF wrote: Fantastic image easy to make out every ventral scale, was the dermatitis a result of too damp an environment or is there another cause?

The result of poor captive care, I'm afraid..... Damp and dirty!

The current squish box I have is cut from a piece of plastic packaging with very soft foam. It works well enough for keeping them still (though snakes tend to stop moving even if you just place a finger on their back). First results of the scan, the neo I missed yesterday was easy to collect from the exact same spot in todays murky overcast:

I don't think we had full resolution on the scanner, but the result is acceptable though it took a few passes to get the whole underside in good enough focus, bearing in mind we were scanning through the base of the squish box the result is impressive and the whole process easier than using a camera, it is also dimensionally correct which is ideal. Good enough for ID, and I have one shot of the tail that will allow a scale count.

Next I'm going to try an open ended box so I can squish them directly to the plate on the scanner

One last thing, had a hunt around for some software to take measurements directly from the images, quite a bit of commercial stuff, but the best I found is a free one called http://www.grelf.net/download_app.html#N917587 - GRIP . It allows you to draw a free hand curve and return its length after calibrating the image, thus easily measuring SV and tail length - something that photoshop doesn't have. If anyone knows any other software that might be of use I would be interested.

GemmaJF wrote: Next I'm going to try an open ended box so I can squish them directly to the plate on the scanner

Yes.  It's best to have the animal directly on the scanner plate.  When I do it, I don't attempt to restrain them or keep them still in any way.  I just wait until they settle then start the scan.

http://www.serpwidgets.com/Apps/apps.html - http://www.serpwidgets.com/Apps/apps.html

This link should take to a snake measuring application....(if I posted it right)

adamanteus wrote: http://www.serpwidgets.com/Apps/apps.html - http://www.serpwidgets.com/Apps/apps.html This link should take to a snake measuring application....(if I posted it right)

The link works, just what I needed and much easier than trying to draw a curve with the mouse

The problem I had with neo unrestrained was he would keep his head up all the time, might need to let them cool down a bit more as he was very keen to hide under the scanner

Gemma,

can I ask, when are you hoping to recapture to recheck the ventrals? next month, next year? those patterns will definitely warp as they grow, they cannot possibly remain the same. How will you be sure that they will be the same snake? If they are completely different, it could give a general indication, I grant you, but categorically, nah, I don't reckon. Besides which, don't you think all that partial crushing and flashing lights is a good idea????

R

PS,

Im just waiting for the Japanese to come up with a microchip tracker that sticks to one scale like a tick - now that will be progress.

Rob you assumptions contradict at least three papers where individuals were 'tagged' by the first 20 ventrals. Take a look at the two images on this thread. I can't see any difficulty distinguishing these individuals in the future. Futhermore, as previous studies were capture recaptures of adults I should be able to establish if the technique works from neo. Worthy in itself and I have identified adults over several years using the technique. I would anticipate some changing of the pattern, but what off it if it still provides positive ID?

The scan bed isn't a bright light, far less light than a basking snake will be exposed to and certainly far less than a camera flash, so no issue there.

Squish boxes, the argument has been done before, a properly restrained animal is less stressed than one in the hand which needs to be gripped at some point. Partial crushing is a silly term and likely to give completely the wrong impression of what is being done - I assume you do not realise it has been used as a standard technique for GCN ID for years.

Adamanteus has already stated that it is possible to get the scan without it, so I will find the best technique for me and the animals that is least stressful for both parties. As it is the one that was scanned today must have been one of the smallest grass snakes I've ever  handled and it was returned without harm.

PS Rob, if you want to drop by at any time and see what I'm up to first hand you are always welcome, you will see that I'm being very careful and minimising the handling 

I was just messing around with the scanner, to see how easy it is to get a clear picture of the first 20 ventrals, without 'squishing' the snake.  It isn't easy!  I see your point, Gemma, about the heads up thing..... I'd never really noticed before, as I'm not usually interested in the first 20 ventrals.

I took this scan picture a few moments ago, and noticed a couple of divided ventrals.... irrelevant, but interesting I thought.

Hi Adamanteus (we must discuss that user name at some time) it is an issue, but I'm after the most information for the minimal stress, it appears squishing achieves this. Divided ventals may not be a 'non' issue if it gives another form of ID, I have found with adder it isn't one technique that returns the results but a combination. We might reduce a data set by recording the first 20 ventral scales thus giving a clue to ID, but divided ventrals might just tip the balance to positive ID. It is really a confidence issue as regards to any 'scientific' or precise solution.

Please do come up at some time Rob, your input will be really appreciated, if it is a poor day it would be good to catch up and at least you can see the study area and have a cuppa, a far cry from Epping but of interest as I have a strong belief that pro-active habitat creation is the future as opposed to 'conservation' of what exist we we seen to be losing at an alarming rate.

PS sorry for poor spelling etc, totally pissed and meant to fly back from France tomorrow for the first time, oh well I guess I'm used to people putting up with my short comings on here, but what is the betting I pull it off anyway