There are two kinds of woodpeckers that both are quite similar to each other.
You have got the Green Woodpecker and the Grey-headed Woodpecker.
Both are green on their back, but the green woodpecker has got a dark field around the eyes. So when I first took this picture I was so sure that I had seen a Green Woodpecker, but then it turned out to be a Grey-headed one instead.
This guy (or girl, I’ve no idea witch it is) perched in a three outside our apartment one Sunday. Again I got a lucky shot.
Correction: I’ve done some more research and it might be possible that this is a Green Woodpecker after all, but a juvenile not an adult. I found this site today, and there you can see the same spotted chest as in my picture. Oh well, if there are somebody who knows, please add a comment to this post.