Sure enough, as I made the tea this morning, I heard scuffles and bangs and there was the bird behaving just as P had described. I haven't yet got a picture or filmlet of it but will post one here if I do. But I saw that it was a female (pic below, apols for the poor quality of my bird photography) and, while I watched, she was joined on an endless forage for food on the lawn and shrubs by a male and two other hens.
Hence my question, which has yet to be resolved as my brief foray on Google only turned up lots of stuff about American novels with 'blackbird' in the title plus references to the Beatles' famous lyric 'Blackbird singing in the dead of night...' On which score, you may be interested to note a reference to the Fab Four in the blackbird's manifesto for the recent vote on Britain's national bird.
This is generally assumed, including by me, to be the robin, which won the last such vote back in the 1960s. But it may be toppled from its perch after the poll of a shortlist of ten which was held appropriately on the UK's General Election day last Thursday. The counting process isn't quite as swift as local authorities'. Some 213,000 people have voted which is impressive, but the result will not be disclosed until June.
Here's the blackbird's manifesto from a nice piece in my old paper The Guardian. You can read all its rivals' claims here.
The black bird is expected to make a strong push, relying heavily on the “Beatles effect”.
Nature’s Home editor Mark Ward said a vote for the blackbird was a vote for joy.
“That’s why you should vote blackbird – for no other reason than it being the bird that makes you smile. And who doesn’t need more smiles in their life? Whether you live in town or city, you don’t have to look hard to share some precious time with a blackbird. Vote for your favourite neighbour. Vote blackbird - and smile.”
The Royal Society for the Protection of Birds' website meanwhile observes:
Blackbirds tend to be solitary birds. Small feeding and roosting aggregation sometimes form at good sites, but there is no proper social interaction.
And finally, I noticed that the window in question gave a very good reflection of me when I pottered past en route to the moth trap (which contained only five Flame Shoulders, the Clouded Drab below, a bee and a slug, hence all this stuff about birds). I suspect the blackbird has noticed its reflection and fears that yet another bride is hoping to move in.