Squatter with Bird is a great combination of timing (good fortune?)
Yup. Was taking another shot (which was boring), then saw the pigeon, re-focused as best I could and pressed the button. Had some awareness of the group of people walking up behind, but their alignment and the crouch was pure luck.
I had been thinking again about the problem of the brain guessing what should be there... but I think there is another side, that you can react without seeing things. Ie something in my head maybe had time to recognise that something was happening NOW and I should press the button, even though there wasn't time to render it as part of my visual perception. There seems to be an implausibly high proportion of photos where there is something going on that I wasn't aware of when taking it... and some days it's there in lots of photos, and other days... nothing.
But luck does funny things, too... :-)