For anyone who has any questions about wildlife in Britain there is a fabulous resource that’s free and available to anyone. This is the Wild About Britain website, and in particular the forums there. You can ask any question and get an answer from a huge range of experts and enthusiasts.
I asked the question about badgers being able to see the infra-red light from my night vision scope, and one response seemed to match my experiences exactly. This is from a WAB member called stripee:
Yes they can see it and always react. Some more nervously than others. I have a night vision scope with infra red. The badgers, foxes etc don’t like it shone in their eyes. I try to shine it for short periods and not directly at them.
If you look at your scope when the red light is on from the front it can be seen for a long distance at a certain angle. I had heard that badgers don’t see red light, but it just isn’t true.
This is good. This backs up what I have observed. It isn’t scientific proof yet, but it adds to the anecdotal evidence.
I’ll keep searching and see what else I can find out. In the meantime I’ll also try some informal experiments and see if I can get some more evidence. There are more formal experiments that could be done to prove the matter one way or another (I’m thinking of a version of the Skinner Box with an infra-red stimulus) but I’d need a fairly captive population of badgers to try it on. If any biology students are looking for an idea for a project, let me know…