Blackbird Song

[Richard Green]

Just to say a Blackbird has been singing an unusual song outside my house for approximately the last 8 weeks.
The beginning is not dissimilar to other Blackbirds but it ends in a fast repetitive whistle of perhaps 3/4 notes which are then repeated 3 to 6 times.
Does anyone have past experience of this or even a viewpoint on why the difference in song may occur? 

[ETJ]

This is a rather late response to Alistair's query about Blackbird song. Blackbirds are able to learn tunes. A few years ago, a local bird sang accurately the first six notes of 'I was Kaiser Bill's batman',a  Roger Cook/Roger Greenway tune which was a hit for Whistling Jack Smith in 1967 (there are videos of it on YouTube). The performance was so distinctive that even my non-birdwatching neighbour noticed it. The next year, another Blackbird further down the street tried to sing it but was not as proficient.The first bird can only have picked it up from someone whistling it,while the second bird was trying to copy the  first. I'm fairly certain that I read about a Blackbird that copied the whistle that a man used to attract his dog.
I wonder if your bird was brought up close to a Song Thrush?

Eric

[ETJ]

Whoops! Sorry for getting the name wrong.

Eric

[Richard Green]

Thanks ETJ i do have an audio recording of this bird on my phone which doesn't do it justice but enough for one to get to get the gist