From a hospital bed

I had to spend a couple of nights in hospital last week after a short, "routine" operation. It was mostly very boring, though I managed to finish a very difficult book on chaos theory that I have been digging into for some time. But whilst lying there, at dawn, arount 5am, I heard the yaffling call of a Green Woodpecker and then a Syrian Woodpecker, from my 4th floor room...