Here you go Patti - seems I used one of the 'other' variations in spelling, but otherwise its essentially the same.
The 'not a dicky-bird' phrase indirectly derives from the tweeting sounds made by the birds. 'Dicky-birds' became established as a Cockney Rhyming Slang term for 'words', in the mid 20th century. The first record of it in print is in the 1932 'P. P.' Rhyming Slang:
" Word... Dicky bird."
So, 'not a dicky-bird' means 'not a word', i.e. silence, especially in the context where a spoken or written word might have been expected - for example, 'Jack said he would write, but I haven't heard a dicky-bird from him for weeks'.