[Leica] OT: Bird ID and habits - Help needed

[Philippe]

Could any of you help us put a name onto this species, 
and perhaps explain why this young fellow has been repeatedly banging against this and the opposite side window of our living-room since early morning yesterday?

http://gallery.leica-users.org/v/Phileica/Oiseaux/Birdy-8416.jpg.html
and the next two - all three can be viewed large

Thanks in anticipation

Philippe and Alice who fear for its life and would like to understand how to protect it.