I live in Surrey. Talking with local birders, we have all noticed a dramatic decline in the number of little owls in our area. I think that the decline set in at about the time of the very hard winters (2012 and 13, I think they were). According to Birdtrack, reporting rates are now down to about 1/3 of their historic average levels. My mates and I reckon that the decline around SE Surrey is more like 90%.
I would be interested to know whether people in other parts of the UK have noticed marked declines in little owl numbers. And also if anyone has any theories as to what is happening.
There do seem to be rather more barn owls about in the last few years but do they predate little owls to a significant extent?
Another theory is that increasing buzzard nos. have impacted the no. of little owls. Or perhaps they have made the little owls more cautious about perching openly.