Colin Stewart wrote:

When Bing was in London probably in the 60's he took part in a natural history programme. He was interviewed about his background in country pursuits, on his knowledge about the wild life that he saw, heard and hunted. I remember him imitating the call of the Great Northern Diver or Loon (as in his friend Johhny Mercer's "crazy as a loon). He used to go hunting with Phil Harris.

I will try to find a tape I made of that broadcast to put a date to it.

Colin.

Colin,

Welcome to this discussion group.
I might have mis-identified the programme but the one I remember was somewhat later than your memory suggests. It was called 'Sounds Natural'  and I found it very interesting because it took Bing away from the normal topics favoured by interviewers. He was in his element talking about his love for the natural world.

In 'Diary of a Lifetime', Malcolm pins it down to a recording date of July 28 1975 and broadcast date of January 26, 1976.  As I remember Bing imitated several bird calls and talked about their habitats, appearance and characteristics.