RAUK - Archived Forum - Refugia question

Mark,

I've not used Coroline, but as for refugia in general, I'd bet you could find an adder under any size. Personally I find tins that are at least 2ftx2ft work better than smaller tins, and I'd go as far as to say 3ftx2ft works better still.

It does depend upon the site though; if there is high public pressure, you may need slightly smaller tins so they remain inconspicuous.

On a final note, I'd suggest that tins are not essential for determining absence/presence for adder as it is a visible species; although having tins as way-points to ensure rigorous survey isn't a bad idea.

Of course if Ca is a possibility but unknown on the site, then you pretty much have to use refugia.

That's my tuppence :P

Steve

Try an area of 0.5 to 0.65 m, I find this the best size to handle in the field and it gives good results.

Our standard size for corrugated bitumen is:

95 cm x 68 cm (area = 0.65 m^2)

At this size we get three refugia from a standard sheet of 'Gutta'.

Corrugated bitumen at this size has proven very successful for recording all four widespread species and in particular I'm confident that they will produce adult adder

Heh,

95 cm x 68 cm (area = 0.65 m^2) = 3ftx2ft near enough. I sense violent agreement :P

LOL Steve, I thought I best go metric, but yep 3ftx2ft it is

Mark, we often get vivi lizards under bitumen and on. They usually start their basking sessions under then pop on top once they are warmed up. (Also look under the felt for any that jump off the top when you approach, as they often appear under the bitumen soon after)

If you only see lizards 'on' refugia I would suggest you could start your sessions at slightly lower air temperatures or at slightly earlier times and get sightings 'under'. The bizarre thing is that they start both morning and afternoon sessions 'under' regardless of ambient temperatures. I made a graph a couple of years ago that showed this quite dramatically.

Let us know how you get on with the kitchen lino, we've been getting quite a few reptiles from under hub caps on a job we are doing for highways at the moment, so it is always worth trying something new!

Be interested to know how you guys fasten your tins etc. down. Any I've put down in the past few years have had a large rock put on them. The established ones I look at are fixed with wire and a stake driven into the ground.

I had a nasty happening with a grass snake the other year  when lifting a tin it slipped through the twisted wire as I lifted the tin and the wire tightened round its middle and it was stuck. I had help and tried to reverse the procedure to slacken the wire but it was difficult. The snake got free eventually but I'm not sure it would've survived. Last year I looked under a tin and found two dead adders lying parallel. They were a bit decayed, so hard to see why they died. This year under the same tin as I lifted it an adder got stuck in the twisted wire as I lifted the tin and the poor thing was so badly injured and died within 10 minutes. It died in the same position as the 2 I'd found dead there previously and I think they too died when someone lifted the tin and they got squeezed. We pulled out the stake and weighted the tin with a rock. Perhaps some sort of chain link that was fixed would be better than twisted wire.

Interesting....

None of the tins in my area are fixed in such a way. They are positioned out of direct wind, shielded by vegetation, often placed such that they are 'pinned' by the surrounded bushes, yet can be freely lifted.

We've had one site, that I know of, where local yobs managed to find some tins and bashed any snakes found under them. The tins were immediately removed. I have a slight concern that by numbering the tins we may have provided them with a list of other tins to hunt down.

(One thought that occurs; If fixing is required, due to weather and terrain, perhaps the fixing could be made to be very short, or even rigid along one tin edge, effectively making a hinge. Would be hard to imagine an animal getting caught in such a mechanism).

We would not usually secure refugia in any way. Like Steve we simply place them where wind disturbance is minimal and once they bed down there is not usually an issue.

We are currently doing a job for Highways where we have refugia within 0.5m of a busy motorway. Due to practical considerations we have little vegetation is some areas and the felts are exposed to the full blast of traffic slipstreams. Our solution has been to use tent pegs passed through holes in the felts to secure them. This works well for flexible materials (roofing felt/bitumen) and we are confident that they won't end up on the carriage way. (amazingly we are locating small numbers of slow-worms in this apparently inhospitable environment).

Suzi,

Just out of interest, if this is the case why were the refugia secured in the first place?

No expert here, I always go home with more questions than answers!

Like why on a current capture project are the vivi lizards and slow-worms in discrete pockets when the habitat inbetween appears perfectly suitable? Why do some of the pockets contain only vivi lizards and others only slow-worms??

Do vivi lizards actively avoid Vb? I've data from two sites showing low density of vivi lizards in areas favoured by berus within otherwise widespread and locally abundant lizard populations and reasonably uniform habitat. Do the lizards know to avoid Vb foraging areas or is it just that the little adders have eaten them all??... I could go on forever

Sounds to me that whoever originally put down your tins was tired of public disturbance, a major irritation at some sites.

Do the lizards know to avoid Vb foraging areas or is it just that the little adders have eaten them all?

I watched an adult female common lizard emerge from heather into a basking place, see an adder, and run. It ran a lot further and faster than a lizard normally does when it sees me. But I've also seen naive little black youngsters taking almost no notice. And since the males tend to have territories, I imagine the answer is a bit of both. 

I love the observation of the lizard turning tail and running for its life!

I've seen Vb and Lv bask together also, but have observed this more at communal hibernaculum. I have strong correlation in a couple of data sets for sites supporting both species however of a lower density of Lv in foraging areas, these often being distinct from hibernation banks/features.

I think I'm right Suzi in saying that juvenile adder prefer lizards and as they mature become more mammal orientated, Tony may be able to confirm this.