For the last few weeks I’ve been visiting new sites looking at habitat suitability and putting out reptile survey materials. This has all been done with land owner permission, which is vital. You could be accused of littering as well as trespass if you went around putting out reptile friendly survey sheets wherever you thought looked suitable.
These can be made of a mix of material from old metal sheets (corrugated iron being a favourite of herpetologists). corrugated roofing Onduline, the black bitumous stuff you can get from DIY stores. Roofing felt and rubber car mats, as well as carpet tiles can all be used.
So what are they for? They offer a refuge for reptiles to hide under, hence one of the common names ‘refugia’. Other names include Artificial Cover objects abbreviated to ACO’s. Tins, felts, tiles or mats. The reason for providing these on a site is to make life easier for the surveyor as much as to offer the reptiles a new home. They all warm up quickly thus allowing any reptile under them to get to ‘activation temperature’ without exposing itself to bask in direct sun and running the risk of being a predators breakfast. In the right place an ACO can have several reptiles under it. From the surveying point of view this makes life easy. Rather than having to creep and peep everywhere you simply wander from tin to tin and have a cheeky tin tip to see what is underneath.
The key to success is location location location. If you scatter a bunch of ACO’s about without any thought to what other landscape features are on site, then you can almost forget results. I’ve been to sites where ACO’s are put out almost in the middle of fields with no dense vegetation around them. Totally exposed and on bare earth or at least very short vegetation. Unless your refugia are placed carefully along edge habitat, next to dense vegetation, in amongst thickets of bramble or nettle or next to log or rubble piles then don’t count on them being used too often.
If you can angle or position your refugia so that they can be seen and scanned from a distance using binoculars all the better. The risk with this is, in areas with public use, they may get interfered with. I have known ecologists placing refugia out early in the season, return to site to find all their tins neatly stacked by the gateway.
Reptiles don’t like to venture out across bare ground if they can avoid it so making sure your tins are in the right place from the offset helps massively. Out on wild and windy moors tucking them amongst heather clumps so they are hidden, anchored and sheltered from the wind helps. the only drawback is visibility from any distance is difficult. So your approach has to be very stealthy. Anchoring them with either logs or stones helps with lighter materials like the Onduline, roofing felt and carpet tiles. Strong winds can alter your transect dramatically and refugia in trees and hedges isn’t much use to lizards and snakes. Scattering a little foliage over the tins in areas with regular public access helps to disguise them a little. Like the picture above, the refugia is in front of the green tree stump and has the log across it.
Putting them out on site early in the year allows any scent from humans to dissipate through weathering. Wildlife will get used to the new object over the course of a few weeks until eventually they begin to use it. Other wildlife will make use of ACO’s and it is common to find ant nests, rodents and toads under tins and felts.