I never realised that we humans can pick up regional variation in birdsong until I heard the children's TV show 'Postman Pat' set in the Yorkshire Dales with a recording of a skylark in the soundtrack.

I really choked.

I was long ago transplanted to the South of England from Yorkshire. I have heard larks down here, and never thought they were any different to the ones at home, but I supose subconsciously I had learned the larksong of the 60's in South Yorkshire.

I still listen to skylarks, but now I wonder if I return to Yorkshire will I find the song to have changed, and might it be - ordinary - if such a sound can ever be so described.