Curiosity on the beach

Please be warned that this post involves digestive processes some may find disgusting. Skip it if you do...


Walking on the fine white sand of Caribbean beaches, it amuses me to think that it is almost entirely composed of coral that has been chewed, swallowed, and, um, "processed" through parrot fish.

I had thought nothing like this existed on our Cape Cod beaches, other than some shells smashed by seagulls (often on rocky beaches, but sometimes on a favorite rock like this one)...

but this does not involve passage through a creature.

However, a few weeks ago, on a sailing adventure to Little Sipson Island in Pleasant Bay,

I found small piles of waste filled with the broken shells of blue mussels.

Eyes opened, I looked at the beach again and noticed spots, small blue patches where these piles used to be...

and the sand itself has small bits of blue shell everywhere. I know that the few-percent contribution to these beaches pales beside the nearly 100% Caribbean fraction, but still pretty darned interesting.

One question that springs to mind is what species did this? Gulls? Cormorants? (A bit of quick research brings up eider ducks, corroborated by the fact that we DID find about ten mummified remains on the island that could easily have been eiders.)

One final question that springs to mind is whether these little piles are more like owl pellets, regurgitated stuff too troublesome to run through the normal one-way digestive tract, or whether it did, indeed, make the passage. The web says eiders do not regurgitate, so that leaves only one path, as it were...

So much fun to go the beach with curious eyes!