- Written by Clyde McMillan-Gamber Clyde McMillan-Gamber
Dunlin, sanderlings, ruddy turnstones, and purple sandpipers are small shorebirds that nest on the Arctic tundra. However, many individuals of each kind winter along the Atlantic Ocean coasts of New Jersey, Delaware, Maryland, and farther south.
Happily, each species has its own winter niche along that shoreline. That spreading of these related shorebirds reduces competition for invertebrate food among them, though there is some overlapping of niches.
Each kind of shorebird is camouflaged on its winter habitat. They are not usually seen until they move or fly, which protects them from hawks and other predators.
Flocks of dunlin, a type of sandpiper that is brown on top, feed on invertebrates in saltmarsh mudflats when the tide is out, exposing the mud. Each bird repeatedly pokes its beak into the mud to pull out aquatic worms and other tidbits until the saltwater comes back and floods the flats again.
All day, every day in winter, little groups of pale-gray sanderlings, a kind of sandpiper, rapidly run after saltwater sweeping down sandy beaches to the Atlantic Ocean. These sandpipers do that to pick up and consume invertebrates the retreating water leaves behind on the exposed sand.
The sanderlings then turn around and run up the beaches ahead of the next incoming wavelets sliding up the beaches. And when each wavelet’s advance is halted by gravity, those sandpipers turn again and follow the receding water down the beaches, picking up invertebrates along the way.
Ruddy turnstones, which are a kind of plover, mostly winter in small gatherings on gravelly shores near the Atlantic coast. These handsome, distinctly brown-and-white-patterned shorebirds have the interesting habit of flipping over small stones in search of invertebrates lurking under them.
Dusky-feathered purple sandpipers winter on dark, wave-battered boulders and rock jetties on the Atlantic coastline. Jetties are human-made walls of boulders that jut into the ocean from the beaches and protect the beaches from pummeling ocean waves.
Little groups of purple sandpipers walk over the boulders, and the mussels and seaweed clinging to them, in search of invertebrates to consume. Pounding ocean waves are the worst danger to purple sandpipers.
These shorebirds are interesting to spot along the Atlantic Coast in winter. Each species is camouflaged in its own winter niche, where the birds hunt invertebrates until spring stirs their hormones to migrate north to the Arctic tundra to raise young.
Clyde McMillan-Gamber is a retired Lancaster County Parks naturalist.