As a boy locally (in Hampshire) kestrels were ten a penny, buzzards an exciting rarity and red kites a fantasy only realisable in central Wales. Now, I see more kites than buzzards and I have only seen one kestrel in the last 5 years despite the many farm and rural walks I go on. In the 1960s as motorways were being built, the resultant verges often left fallow were ideal terrain for bank voles, a staple to kestrels I understand. A decline was noted in the 1980s but they don't seem to be on the endangered lists I can find. And the Hampshire & IOW wildlife trust (to which we subscribe) still describes them as widespread and frequent.
Anecdotal (or other) records from elsewhere in the UK?
Interesting issue, Bertie. There are probably several factors in play here including wildlife protection laws, habitat loss and attitudes towards nature-conservation. I have a few additional thoughts...
1. The decimation of the UK rabbit population. [e.g. for buzzards]
2. Frequency of road kills and significance as a food supply. [e.g. magpies]
3. Road verge management/mismanagement. [Kestrels in particular.]
When we lived in Cambridgeshire 50 years ago we regularly drove to West Wales. Over the years the point of sighting buzzards steadly moved from the Welsh border to our lane in South Lincolnshire by the 80s! As far as red kites are concerned there was only one spot in Wales we found them in the 60s. Now these are frequently seen here. [Post reintroduction of course.]
As far as Kestrel numbers are concerned I'd agree with you: they are less common than they were. Hawk-conservancy say:
"One of the difficulties with this situation is that the exact causes of the decline in Kestrels are not known. Loss of habitat has been suggested, along with decreasing prey populations, agricultural chemicals and lack of suitable nest sites."
I can't argue with that view. See:https://www.hawk-conservancy.org/conservation-research/uk/kestrel-conservation/