Dry Sand Feeding

I noticed that the whimbrels I’ve been monitoring feed further up the beach in the dry sand when the tide is halfway between low and high tide. That’s common behavior at high tide, but resorting to dry sand feeding halfway to high tide seems a little early. I’m curious why the whimbrels would do this. The crabs in the dry sand are smaller than those in the wet sand, so this appears counterintuitive.

I didn’t notice this behavior last year when monitoring whimbrels at a different beach. At that beach, the birds fed in the wet sand up to roughly an hour before the highest tide and often continued to feed through most high tides.

Perhaps the mole crabs restrict how far they migrate up the beach? That could leave the crabs completely submerged and unavailable to the birds at the halfway mark between the tides.

I know that the mating season for Pacific mole crabs has just started. Do mole crabs bury themselves deeper in the wet sand during this time to ensure they are safe from predators? I’ll continue investigating, but if anyone has an answer or even a thought, please share.