This is an open question to any and all badger experts out there. Can badgers see infra-red?
I’ve used my night vision scope twice now (see Fieldnotes: 25th July 2009 – First night vision session and Fieldnotes: 6th March 2010 – A frosty night at the badger sett). On both occasions the badgers have been visibly spooked, presumably by the infra-red light. Of course, this is purely anecdotal evidence – I haven’t done any sort of scientific study – but I’ve spent enough hours watching badgers to know when one is disturbed by something, and all the ones I’ve seen through the night vision scope have indeed been disturbed.
Of course, it might not necessarily be the infra-red. The night vision scope (it’s a Bresser, by the way) may be doing something else to frighten the badgers. It may make a noise that is inaudible to us but audible to badgers, for instance. I don’t know.
So, has anyone had experience of using a night vision scope to watch badgers, particularly with an infra-red torch? Did you notice any signs that the badgers were aware of it? Does anyone know of any research or literature on the subject? Does anyone know if any other animals can see in the infra-red end of the spectrum?
If you have any ideas or experiences, please do let me know. I’ll keep searching myself and let you know if I find anything.
Thanks
BWM
Tales from the Wood - The Diary of a Badger Watching Man 
My money is on the noise the apparatus is making. I know that some of these things make a high pitched noise. Try it on a friendly dog. I won’t be able to try myself until I get mine in a couple of weeks.
I’m not sure if mammals ‘see’ infra red – but of course some reptiles detect areas of heat and cold. Some now say birds of prey can detect heat source of urine trails from rabbits and rodents.
No definitive answer from me I’m afraid.
Thanks Pablo. I have heard of animals being deterred by the high-pitched whine of electronic equipment. This is one of the reasons often given for why Bigfoot has never been photographed by an automatic trail camera (the other plausible reason – that they don’t exist – is rarely considered by the Bigfoot research fraternity).
Lacking a friendly dog, I tried testing the scope on my cat, with predictable results. She totally ignored it, but then she totally ignores everything, so I can’t claim this to be a wholly conclusive results.
Nevertheless, there is some evidence from other people that badgers react to night vision devices. I’ll post this up on here separately.
Try a bat detector (I’ll try and remember to do so sometime) and start at the 17 KHz level and work upwards. 17 KHz is about the upper limit of my hearing; 20 is usually quoted, but that’s teenagers only.
What is likely to be happening is that the LED is being driven by a circuit which is pulsing it on and off at a high frequency; doing so with an LED gives a higher light output than a steady current would. There was also a DERA patent from some years ago for a method of making a super-NV camera + LED system, whereby the LED pulsing was coupled to the camera scan frequency.
The patent meant that you could over-drive the LEDs by quite a large factor and not burn them out. Of course, this would give a big, bright highly-noticeable flickering infrared light, which was why DERA patented it rather than keeping it secret for the military; any attempt to use this in the field would end in the enemy shooting at the light.
However, such a system would certainly make a lot of ultrasonic noise. Another ultrasonically-noisy system is the high voltage generator on GEN-1 and GEN-2 night vision devices, though a CCD camera would be much less noisy I think.
One of the largest scientific studies of badger behaviour that I know of was conducted in the 1950s; the researchers used tungsten filament lamp torches fitted with red filters for badger observation. These produced red visible light and shedloads of infrared right the way from visible down to thermal ranges; the badgers completely ignored these lights, though white light did make them nervous.