I could easily have overlooked this feather if, at the very moment I glanced down, the sun hadn’t shone through a fleeting break in the dense cloud cover and highlighted the tiny splodge of bright blue on one side below the white.

Once I’d picked up the feather and looked closer, I also noticed the faint blue mottling at the other end of the white patch. That blue is an indisputable identification pointer – this is from a Jay, it’s one of the less vibrant and well marked of its wing feathers.