The Bloody Wood by Michael Innes (Penguin, 1977)

 

The setting is a gross parody.  The house party in the country house with its lawns and terraces ... and the nightingale singing in the copse on the hill.

But the hostess is a dying woman and her guests have expectations; the town is lapping up to the village; you can hear the traffic on the arterial road in between the nightingales' songs.

... And those nightingales.  They provide Appleby with the thread which leads to the heart of perhaps the most unpleasant tangle of events in his whole career.

Spoiler alert: The butler did NOT do it.

And there is a butler.  This is one of those British whodunnits where everyone is frightfully upper-crust--even the detectives.  It is a rather late entry in the genre--The Bloody Wood was first published in 1966.  Nonetheless it has all the traditional ingredients, including a country house party where most of the guests have a motive for murder.

Incidentally, if I'm ever invited to one of these shindigs (not likely, I know!) I'm going to say, "Thanks, but no thanks!"  The death rate at these parties is higher than in most warzones.

Kudos, by the way, to the author, who manages to make a reference to Agatha Christie on page  135:

'I suppose it's nonsense,' he said.  'But--do you know? - I never hear of a tape-recorder without remembering some mystery story or another.  By one of those dashed clever women who concoct such things.  Frightfully good.  Only, of course, I don't remember how it was brought in ... Sorry.'