Treecreeper

Treecreeper

The first time I spotted these was slightly disturbing. As the light falls, our eyes switch to using black-and-white vision much more sensitive to movement, but with a sizeable blind spot in the centre of our vision.

Treecreepers move rapidly up and down the bark of trees, and being very well camouflaged are invisible when they freeze. The combination of this with my gradually adjusting eyes made it seem for some time as though the surfaces of the trees were moving, but only when I didn’t look at them…