Christine's walking & birds blog

It's the season for rock-pooling! Sometimes I see nothing but tiny fish darting about, but today there was something spherical and colourful in the crystal-clear water, no more than 2 inches across. Looking it up at home later I found that it's probably a green sea urchin (also known as purple-tipped sea urchin) - Psammechinus miliaris. Confusingly, wikipedia features another green sea urchin with such a ridiculously long scientific name that I can't be bothered to type it unless I discover that that is the correct one!

I don't know what the periwinkle (if it is a periwinkle) is doing on its back, but my ancient Observer Book of Sea and Seashore states that the purple-tipped sea urchin "may camouflage its body with bits of shell or seaweed". In this case, perhaps the sea urchin hadn't noticed that this particular shell was still inhabited! I'm afraid it might have been my attentions that caused it to start moving across the rock-pool until it could partially withdraw beneath a large rock (apparently they lack eyes but do have low resolution vision in their tube feet - Lund University, Sweden).

Bird life included a black guillemot, a summer-plumaged great northern diver, and, far out, a solitary gannet.