Developing SmallMammalCam

I have been experimenting.  The aim is to adapt the trail cameras so they can record small mammals and still produce a pleasing video in a natural-looking setting.  I started off setting the camera to look through a hollow log.  The bank vole was happy to oblige but because it is quite an open and exposed situation it grabbed a seed each time and dashed into cover to eat it

The next step was to build a wooden tunnel to house the camera and to provide the animals with a bit of cover.  It had a perspex roof to let in light and a tube of bark as a lining to be more photogenic.  I was using a Wingscapes BirdCam Pro which has adjustable focus and records in colour at night using white LEDs.  Lots of trial and error with the focus, the strength of the lights, the angle of the camera, etc.  To start with the camera wasn't a tight fit so the animals came in beside it and were often facing the wrong way or sitting right up against the lens.  I made lots of design modifications but a limiting factor is the very shallow depth of field with this camera.  I did, however, get some promising pictures of bank voles, common shrews and wood mice.  Although wood mice are mainly nocturnal they don't mind the bright lights.  The camera proved difficult to aim down the bark tube and the narrow depth of field is a problem but you can at least see the potential here.  The sound isn't very good on this camera either and it has a colour cast which is difficult to correct with iMovie.

The highlight was the one animal I really wanted, a weasel.  Unfortunately a bank vole had pulled a bit of ivy into the field of view and the weasel was mostly too close to the camera but nevertheless it was quite exciting.  You can hear a wren's alarm calls in the background.

After this I decided to try the Browning cameras.  They have better colour in daytime but only infrared (black and white) at night, don't have adjustable focus and are only sharp beyond about 2-3m.  I have regularly been using +0.5 dioptre lenses from reading glasses to get better pictures of the otters at about 1-6m so I decided to experiment with stronger lenses using what you might call the Goldilocks Principle.    First I tried +4 dioptres but that was too close.  And +2 dioptres was too far away.  And +3 dioptres turned out to be just right, with a depth of field from 30-40cm.  I first tried it out with an open-ended and unlined box.  The disadvantage is that the animals feel rather agoraphobic and grab some food and dash for cover.  Occasionally the bank vole will sit for a while.

The shrew won't.  It moves so fast that often the camera can't cope and it either misses it altogether or just gets a view of its disappearing tail.  Sometimes the shrew returns while the camera is still recording so then we can see it.  I put a few very brief clips together.  This is in real time, not speeded up!

It is almost impossible to see what is going on so I slowed it down by ten times.  The super slow motion video shows that the shrew is choosing a sunflower seed every time, which surprised me because I had offered dried mealworms as well and it is an insectivore.  Notice that it runs so fast that often all four feet are off the ground.  And its brakes don't work very well.  It looks a bit like a cartoon character.

The Browning camera with a +3dioptre lens really is a step up in image quality so I am going to stick with that.  The next stage will be to make a more natural setting while still allowing in plenty of light in the hope that the animals won't dash off immediately.  So I plan to line the box with bark and close in most of the open end.  I'll post any interesting footage here and hope the weasel returns.