Thank you Graham. Yet another instance of how easy it is to be deceived by aural observation alone. I admit I didn't know Jays were as adept mimics as other corvids.
It is worth googling 'bird mimicry'. There has been limited research into the topic of why birds mimic and the results appear somewhat speculative. The link to the most informative site I have found is
http://birding.about.com/od/Sounds/a/Bird-Mimics.htmWhen we lived at Nocton I was often persuaded to dash outside to see the migrating curlew passing over only to find myself fooled by the starling singing from the rooftop. I suspect this was a case of a varied repertoire being utilised to impress a mate.
John