I've moved to a new desk at work that has a much better view and have just started a list. This was prompted by a sparrowhawk doing a display over the trees (a bird I normally only see the rear off as they disappear). Also on the 'sat at my desk list' is magpie, crow, buzzard, pigeon, heron. (until I take in some bins, I can only ID large birds!).
In the decade I've been on the site, I know I've seen: green woodpecker, kestrel, red kite, cuckoo, stonechat, robin, pied wagtail, blackbird, goldfinch, and swift. I need pay more attention to the common small stuff which I have almost certainly seen but which I failed to commit to memory.
I saw my first and only woodcock on the drive in one morning but just outside what i'm counting as the site boundary.