Sandpipers dig in wet sand and mud to find tiny animals like worms, small crustaceans, insect larvae, and sometimes to graze on a thin, slimy layer of algae and microbes called biofilm , which coats the surface of tidal flats.

Quick Scoop

What sandpipers are actually digging for

When you see sandpipers “sewing” their bills in and out of the sand at the water’s edge, they’re after:

  • Marine worms and other buried invertebrates.
  • Tiny crustaceans such as sand fleas, small crabs, shrimp, and other beach “bugs.”
  • Insect larvae and small insects in the wet sand or shallow water.
  • Snails and other soft-bodied shoreline creatures.
  • A microscopic but energy‑rich slime on the sand called biofilm, made of bacteria, algae, and other microorganisms.

Their bills are packed with sensitive pressure receptors that let them “feel” hidden prey under the surface without seeing it, so that frantic digging is a kind of super‑powered touch‑feeding.

A hidden favorite: biofilm

Recent research has shown that for some small sandpipers, a big part of the diet is that slippery biofilm coating mud and sand.

  • They use tiny, brush‑like structures on their tongues and the tips of their bills to scrape and pick up little packets of this slime.
  • Biofilm is extremely energy‑dense and helps fuel their long migrations along coasts and estuaries.

So even when it looks like “they’re just poking nothing,” they might be grazing an invisible buffet spread across the tidal flats.

Simple example to picture it

Imagine a wave pulling back and leaving the sand glistening.
In those few seconds before the next wave, sandpipers rush in, probe rapidly, and grab: a buried worm here, a sand flea there, and a quick “lick” of biofilm off the surface before they dodge the next breaker.

TL;DR: Sandpipers dig mainly for buried worms, tiny crustaceans, insect larvae, and snails, and many species also “graze” an invisible, energy‑rich biofilm growing on wet sand and mud.

Information gathered from public forums or data available on the internet and portrayed here.