Day 14.002: Mussels flexing

I've written before on more than one occasion about the gulls carrying clams up above the beach and dropping them onto the sand to break them open.

The other day, we saw a gull behaving similarly, but what it was holding in its beak and dropping was clearly not a clam. I worked out what it must be - a large mussel with a bit of kelp attached to it - a not uncommon sight, but nowhere near as common as the surf clams.

Then we noticed that this particular stretch of beach had a large number of exactly this arrangement:

I'm not sure what causes this "sorting-effect" at the beach where one section is all pieces of driftwood, another all snail shells etc., but we've observed it on several occasions - but this was the most specific example any of us could think of.