This effect can be caused by artificial changes as well as natural ones and it affects not just humans, but other animals and also plants. I received an email recently from someone I had trained last year on a Pathfinder course. They had spotted something on holiday that puzzled them initially until they cracked it:

‘We spent our time in Majorca soaking up some rays. Interestingly I was looking at some trees that were leaning across the pavement forcing us to duck or walk in the road. The first thing that crossed my mind was why they were doing it, as they were leaning north. Over the next few sunny days I realized that the building on the other side of the road was blocking most of the light and the trees were in fact getting most of their exposure from the reflection of a glass building.’

Sometimes this effect leads to harmless anomalies, but for many animals it can be much more serious, as this article summarises.

Very occasionally the aim is to harm animal species not protect them and the author of this study has suggested that it may be possible to, ‘to create massive polarised light traps to crash bark beetle populations.’ It takes all sorts.