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basking temperatures of common lizards: |
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jopedder Senior Member Joined: 24 Jul 2003 No. of posts: 55  View other posts by jopedder |
Posted: 08 Sep 2003 hello again all, I have another surveying question for all: what is the best time of day to check tins? Actually I know this is the wrong question as what I actually need to know is what body temperatures the common reps need to get to in order to become active. I have recently purchased a thermometer to check air temperatures to tell when to stop checking tins in a morning and to see what time the temp drops to below 20 in the afternoon, but all this is usuless without knowing what temp the reps need. some not entirely scientific sources suggest 30c for common lizard, 12-20 for grass snake and 8-16 for adder, any idea if these are correct or what temp slow worms require? sorry for the spelling mistakes but my time on the library computer is nearly up and this machine will switchitself off! many thanks Jo
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GemmaJF Admin Group Joined: 25 Jan 2003 No. of posts: 2090  View other posts by GemmaJF |
Posted: 09 Sep 2003 The figures for selected temperature in Beebee and Griffiths are, slow-worm 23 c Vivi lizard 30 c Grass snake 29 c Adder 33c taken from Spellerberg (1996); Avery (1997); Gaywood & Spellerberg (1996) selected temperatures being those the animal would maintain in an unlimited situation, activity starts at much lower temperatures of course - though if undisturbed under a tin I would guess they would wait until they reached the species preferred selected temperature. The time under tins would vary on how long the animal actually needed to reach this temperature and with the vagaries of the UK weather I'm sure there are no hard and fast rules. I've little experience of tinning other than the survey Lee Brady has set up in Kent, I find between 8:30 BST and 10:30 BST the most productive in the morning and if doing an afternoon check start after 5:00 BST - certainly plenty of slow-worms have shown up. A lot though must depend on the topography of the site as to exact times that are ideal. I think these were the times you suggested as best Lee? Gemma Fairchild, Independent Ecological Consultant |
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calumma Senior Member Joined: 27 Jun 2003 No. of posts: 351 View other posts by calumma |
Posted: 09 Sep 2003 Gemma: I tend to work in GMT 
It's easier to predict morning surveys and the times you mentioned are reasonable. Afternoon times can be more tricky. During the summer, temperature under refugia increase rapidly in the morning but tail off very slowly in the afternoon. However, during spring and autumn temperatures can drop off much more quickly and refugia material can be very important. The afternoon time you state is fine during the summer, but I would tend to look from 1400 GMT during the spring/autumn (depending upon prevailing weather).. It is also very important to consider what the previous day's weather conditions have been, particularly rainfall and night time temperatures. Weather during the day can also strongly influence results. Showers with intermittent sun can produce very good results. Incidentally I recorded an adult male adder under a tin in one of my large woodland sites today at 16:29 GMT. Lee Lee Brady Kent Herpetofauna Recorder | Independent Ecological Consultant |
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GemmaJF Admin Group Joined: 25 Jan 2003 No. of posts: 2090 View other posts by GemmaJF |
Posted: 10 Sep 2003 Just thought it would be worth mentioning that we started out today at 1400 GMT, we found adult viviparous lizards, very sluggish 7 under tins 3 under mats, strong westerly wind, overcast with showers, strange though only 1 slow-worm, last week starting at 1500 GMT I recorded mostly slow-worms under tins and mats and juvenile viviparous lizard only on top of them. Suggests slow-worms may use them a little later in the afternoon than adult viviparous lizards?
Gemma Fairchild, Independent Ecological Consultant |
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GemmaJF Admin Group Joined: 25 Jan 2003 No. of posts: 2090 View other posts by GemmaJF |
Posted: 10 Sep 2003
Here's a quick plot of animals found under/on tins over the last few weeks vs. time, It's a small data set: 19 slow-worms and 40 viviparous lizards Total of 50 refugia, 25 tins 25 roofing felt but it is beginning to show a trend. (I admit entirely that it may be influenced by greater survey effort at the times Lee suggested!). Though I guess such plots could be useful to track trends at a given site.
Gemma Fairchild, Independent Ecological Consultant |
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jopedder Senior Member Joined: 24 Jul 2003 No. of posts: 55 View other posts by jopedder |
Posted: 14 Sep 2003 Thanks for your information, although the few afternoon checks ive done have been later than your graph suggests is optimal, the morning survey times do match what I've been up to, but I've not been turning up reps. A lot of the sites I've been asked to survey are completely unsuitable habitats, but there are a few gems amongst them that 'should' have reptiles in. Maybe I'll have better luck next week! |
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GemmaJF Admin Group Joined: 25 Jan 2003 No. of posts: 2090 View other posts by GemmaJF |
Posted: 14 Sep 2003 The data set I have so far is too small to compare the materials vs. time, though I find animals under both during the time window given and it would be interesting to see if there is a significant difference between the materials. The time when both become too hot to expect to find animals seems about equal, though I've a feeling the roofing mats take longer to cool, so do have extended use in the evening and possibly on overcast/unsettled days. Lee, David and Tony have all stated elsewhere that there is often no hard and fast rules and results can vary from site to site as to which materials are the most effective. So far there is no greater preference shown by vivi lizards or slowies for either material for this particular survey. Interestingly this site also has a lot of carpet squares left over from a previous survey and also from abandoned cars, they have turned up a few animals on days where tins and roofing felt have had poor results, I guess due to different thermal properties of the material. We are using the pebbly stuff, it seems pretty good for lizards and I have found vivi lizards still asleep early morning, suggesting they use it as cover overnight as well as to thermo-regulate. From what little experience I have, I would agree with LeeÆs view that using a mixture of materials is the best way at any given site, rather than relying on a single material and this also seems to be wise with the unpredictable weather in the UK. Just as an addition to the graph above I also plotted survey effort over the 7 days the data was collected. I found the greatest effort was about an hour later than the morning peak for finds, suggesting it would be worthwhile making an earlier start in the morning. Gemma Fairchild, Independent Ecological Consultant |
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GemmaJF Admin Group Joined: 25 Jan 2003 No. of posts: 2090 View other posts by GemmaJF |
Posted: 14 Sep 2003 revised graph, horizontal lines show survey times,
Gemma Fairchild, Independent Ecological Consultant |
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calumma Senior Member Joined: 27 Jun 2003 No. of posts: 351 View other posts by calumma |
Posted: 14 Sep 2003 Gemma: although your dataset is not complete your observations tally with my own. There is a trend for viv lizards to peak before slow-worms in the morning and to be seen again later in the afternoon. I suspect that this is largely due to viv lizards basking on refugia rather than under. Your note about sleeping animals under refugia is quite true. In fact animals will also hibernate under refugia as well, so care must be taken not to disturb refugia during the winter. During management work at a site in Canterbury we found some old carpet tiles. See what we found underneath... 
All tiles were carefully replaced and the area left undisturbed! Lee Lee Brady Kent Herpetofauna Recorder | Independent Ecological Consultant |
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Gemma Fairchild Krag Committee Joined: 14 Feb 2003 No. of posts: 193 View other posts by Gemma Fairchild |
Posted: 14 Sep 2003 Hi Lee, as you know I've been recording viviparous lizards as "on" or "under" mats, I think they often start off under the mat then use the upper surface once they have warmed a little and perhaps feel less vulnerable. I did notice on the most unsettled day of survey so far, wind, rain and cool we found a lot of adult viviparous lizards under the refugia around 1400 as mentioned above, suggesting they change how they use the refugia with conditions. One would guess that if observations were all of lizards on mats, an earlier start might reveal good numbers under refugia during the warm-up period. ----RAUK e-Forum---- 
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calumma Senior Member Joined: 27 Jun 2003 No. of posts: 351 View other posts by calumma |
Posted: 16 Sep 2003 Gemma: when you get time ( ) it would be interesting to see a plot of viv lizards observations 'on' refugia' v 'under' refugia. I have a large dataset to show similar things later in the year once I've collated results from all of my projects.
Lee Lee Brady Kent Herpetofauna Recorder | Independent Ecological Consultant |
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Tony Phelps Forum Specialist Joined: 09 Mar 2003 No. of posts: 575 View other posts by Tony Phelps |
Posted: 16 Sep 2003 Does anyone have any records of fidelity to particular tin for Z.viv. Also I often find them torpid under tin early in the morning then see them basking on top of tin an hour or so later. Tony |
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calumma Senior Member Joined: 27 Jun 2003 No. of posts: 351 View other posts by calumma |
Posted: 16 Sep 2003 Tony: for this level of survey I try not to handle the animals. It is difficult to identify individual vivs without handling (I usually go for belly pattern photos). Repeated handling is likely to cause too much disturbance and result in lower than expected recapture rate. It may be possible to individually identify some animals without handling (e.g. unusual colours or tail breaks). I can certainly do it with some adult slow-worm, adder and grass snake. Lee Lee Brady Kent Herpetofauna Recorder | Independent Ecological Consultant |
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GemmaJF Admin Group Joined: 25 Jan 2003 No. of posts: 2090 View other posts by GemmaJF |
Posted: 16 Sep 2003 Tony, I did notice one individual, that was photo ID'd (mainly to get his spotty belly on the vivi lizard ID page). He was around for a couple of weeks under the same refugia, I'll pick out the records of just how often when I plot the times for under/on tins. Have you seen long-term fidelity to refugia in Z.v? Gemma Fairchild, Independent Ecological Consultant |
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Tony Phelps Forum Specialist Joined: 09 Mar 2003 No. of posts: 575 View other posts by Tony Phelps |
Posted: 16 Sep 2003 About 2-3 weeks max re fidelity of Z.viv, nothing like me 16yr Anguis male. However, up to two months with both male and female sand lizards. Again, often find torpid UT early morning. Tony |
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GemmaJF Admin Group Joined: 25 Jan 2003 No. of posts: 2090 View other posts by GemmaJF |
Posted: 16 Sep 2003 Tony on checking my records it was a period of only five days that I recorded the same individual male vivi lizard under a black corrugated roofing mat, though the survey is still ongoing. Lee, results so far for on/under tins and mats combined:
Seems to be a trend throughout the day of using the under surfaces of the refugia, followed by basking on the surface. The first peak for "under refugia" is misleading. My notes show these animals were mostly found under refugia that were in early morning shade. Those that recorded animals basking on the upper surface, were in full sun by this time in the morning. If adjusted over the entire set for average temperature/time for the study period, I believe the peak would have been to the left of the first "on refugia" curve, or even split. (I'll have to get up earlier in the morning to find out if this actually so Gemma Fairchild, Independent Ecological Consultant |
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calumma Senior Member Joined: 27 Jun 2003 No. of posts: 351 View other posts by calumma |
Posted: 16 Sep 2003 Just for fun here are the temperatures under refugia for one of my sites in Kent. All readings were taken with Tiny tag data loggers. I have selected this day (16th June 2003) because it represents the hottest conditions under refugia for this year (so far). Note that the air temperature peaked at approx 31 degrees. This is not the warmest day of the year (vegetation on my site had grown sufficiently to help screen the refugia later in the year). Also, please note that the air temp was not taken on the site but in my garden (some miles away). It is included as a simple reference. Anyway caveats aside here goes: 
I've not downloaded data for September yet. Lee Lee Brady Kent Herpetofauna Recorder | Independent Ecological Consultant |
- basking temperatures of common lizards |
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