A pebble

"I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."

Sir Isaac Newton.

Yesterday's mystery photograph showed a murder scene.  The victim, a frog, the villain, a gull. By mid-March the small loch in the middle of the dunes is packed with mating frogs and toads The herons and gulls feast on the amphibians but discard the egg-swollen ovaries as they are incredibly sticky. This unfortunate frog had been caught and then butchered on top of a fence post.

So those of you who suggested caviar or fish eggs were pretty close to the mark!