Although many shorebirds are only found in the Arctic during the breeding season, with the onset of fall, many will start appearing along the Massachusetts coast. One example of this is the sanderling (Calidris alba). Sanderlings are long-distance migrants, breeding only on the far northern Arctic tundra, while dispersing to almost all sandy beaches of the world during the winter, including Cape Cod.
Sanderlings are medium sized sandpipers and have fairly distinctive nonbreeding plumage: white belly and breast with grey back and wings, paler than any other shorebird, with a blackish mark at their shoulder. Since their breeding plumage is lost before their return to Cape Cod’s coast, it’s unlikely that you would see a sanderling’s breeding plumage (reddish head and breast) here. Their Latin name is actually derived from their unique light coloring. The genus name Calidris comes from the ancient Greek word kalidris, a used by Aristotle to described some grey-colored waterside birds, while the species name alba is Latin for “white”.
In their wintering grounds, they gather in loose flocks to probe the sand of the wave-washed portions of beaches searching for marine invertebrates to eat. To constantly have access to an area of sand that the waves have just retreated from (bringing invertebrates near the surface) without getting tumbled in the waves themselves, sanderlings are constantly running back and forth in a perpetual wave chase. Their prey includes small crabs, amphipods and other small crustaceans, polychaete worms, mollusks, and horseshoe crab eggs. They will also eat flying insects, such as crane flies, midges, mosquitoes, beetles, butterflies, and moths, if available.
Have you spotted sanderlings or any other winter shorebirds yet?