I have been working on a new project over the last few weeks… to build a number of small chambers for all my mouse, vole and shrew visitors. I plan on building 3 or 4 and then linking them with tunnels. I will place cameras in them and use some for feeding and some for nesting. I would love to get a family to breed in one of these chambers next spring. My prototype has been made out of air drying clay… and I am pretty pleased with the results. Full details on how I built this little ‘Clay Cavern’ are on my website HERE.
The difficult part is not actually the building … but the cameras. You have to try and get the right angle on your subjects… and I like to get the cams as low down as I can, so they are eye-level with my visitors. I think this helps give you the impression that you are right in there with them! The next issue is lighting the chamber. For the creatures to behave naturally and feel safe, it needs to be dark in there, so the only way to light it, is with infra-red… a light that is invisible to them. Most little nest box type cameras come with some IR LEDs on the front… they illuminate the nest box at night so you can see what’s happening. The problem here is that my subjects come pretty close and the IR is hard to control. If it is too bright, then you get ‘burn-out’… areas that are white as the IR is too strong. What is better, is if you can use a separate IR source… away from the camera. The problem here is two-fold. firstly, you then need to pay for a camera AND a separate IR unit and secondly you need two power supplies. By using separate IR, you can position it to give the best lighting. Ideally, you bounce the IR off of a wall or a ceiling as it diffuses the light.
In this case, I have used an old cam that has broken. Luckily, the IR LEDs still work though. To get over the power problem, I bought a little power splitter cable that enables me to power several cams from the one 12v cable. This means I do not have to run another cable back to the house just to power the IR. I used a plastic tub that was about 15 cm deep and upturned it on top of the cavern. I sat the IR cam on top, so it shone through the plastic of the tub. This diffuses the IR slightly so it is not so intense. This gives a better, more even coverage.
I am using a B&W cam to view the cavern. Since it is always on IR, it is silly to waste a colour cam and also the B&W cams tend to give a better image in the dark. Sam Corfield at Heligan has been helping and advising me with this and it is a steep learning curve trying to understand why some night-time footage is grainy and how to get the best cam and image for each individual occasion.
I have put this new cavern cam in the same place as my previous mousecam as I get a lot of visitors. It has been fairly disruptive, so I expect it will take a while for all my visitors to return…. I have already had one vole visitor though… and you can see how much improved this image is now from this screen capture. So watch out for it on my live cams and very soon I will be adding another one, which will be set up for nesting.