Developing OtterCam

It is interesting to see how much things have improved with the trail camera recordings of otters over the past two years.  At first I was pleased even to see an otter but soon I was frustrated by the limited illumination and the poor focus inside 2m or so.  The first development was to use auxiliary infrared lighting with rechargeable lithium batteries. It works but the lights aren't triggered by the otter - they just come on at dusk and the batteries only last eight hours - so they are no use if the otter doesn't turn up until after that, or the following night.

The biggest step forward was improving the close focus by using a cut-down lens from a pair of reading glasses from the pound shop.  To start with I tried +1.25 dioptres which is best at about 0.75 - 3m distance.  Now I use mostly +0.5 dioptres which works over about 1-6m, usually about right for an animal the size of an otter.

And the latest development is using multiple cameras simultaneously.  This has the advantage that they provide each other with extra illumination and offer the opportunity of editing the videos to give a better image.  I have been experimenting with the editing recently and the next video is the most satisfying sequence so far, using four cameras together.  The otters are quite used to my cameras but the camera at the top of the bank was new and the dog seemed unhappy with it.

Here is another sequence of the dog otter a few days later.  This time he was comfortable with, or unaware of, the camera and was scent-marking as he went down the bank.  Here I haven't edited it but have strung together the clips to show how the cameras each switch on as he goes past, improving the illumination.  The third camera on the left had a nearly flat battery so although it switched on its light briefly it didn't record.  This otter has been out of the water for a while and you can see how fluffy and furry he looks.  Also what a powerful beast he is.

And here is the same sequence but each time cut to the next camera as it starts to record.

The next video shows an intriguing sequence.  The dog otter left a scent mark at the top of the bank and went down past the cameras before swimming out across the pool.  One minute later the mother otter was on the bank, having appeared from behind the lowest camera.  She called and then went up the bank as the pup appeared from the other direction, keeping close to the bank and looking (nervously?) across to its left, where the dog otter had gone.  The pup scampered up the bank after its mother and they both sniffed where the dog had scent marked, before the pup added its own scent.  I can be sure of the timings as the recordings were one minute apart on all three cameras.  It is interesting that the dog and the other otters were so close together.

A couple more videos to bring you up to date.  It is much better seeing the otters out of the water and even better in daylight.  Here is the dog otter, again wary of the new camera at the top of the bank.  The new camera didn't record but this one lower down did although it was a bit slow to react so he had already gone past.  See how well the +0.5 dioptre lens works in good light.  It is just a pity the camera wasn't a bit lower (it is now).

And another curious sequence.  A cygnet had died in the water just in front of the cameras.  The mother otter got out of the water, ignoring the swan but sniffing the auxiliary infrared light which I had inadvertently left in view of the camera (and which had a flat battery).  The otter pup was more interested in the dead cygnet and towed it out of view, perhaps intending to eat it.  Next morning I found the cygnet floating in the water snagged in some branches so the pup never got to taste swan after all.

The otter pup is now more or less as big as its mother so I expect it will leave soon to make its way in the world.  This will make it more difficult for me to tell which animal is which when there is only one.

I am very pleased with the images from simultaneous recording from multiple cameras so this is something I shall develop.  What I would really like is trigged auxiliary lighting as well which is probably possible but beyond my ability to develop.