SANDERLING (Calidris alba) – (See images below)
DESCRIPTION: The Sanderling is a small wading shorebird in the Sandpiper family. The top parts (head, breast and back) of the breeding individuals are mottled rusty brown, and the under parts are white. During the non-breeding season the top parts are mottled light grey. The wings are barred with the same colors. The bill and legs are black. Sexes are similar. The overall length of the sanderling approximates 7 inches (18 cm).
NAME: The English name ‘Sanderling’ comes from Old English and means ‘one who chirps on the sand’ (Ernest A. Choate). As for the Latin genus name ‘Calidris’, it means a grey-speckled shorebird. The Latin species name ‘alba’ means ‘white’.
HABITAT: Dry and rocky tundra during breeding season. Sandy beaches around the world during migration.
DIET: The sanderling feed on invertebrates (crustaceans) that it picks in the wet sand. It runs up and down the beaches, following the movement of the waves. The populations migrating back north from South America feed on horseshoe crab eggs in Delaware Bay.
NESTING: The nest is a scrape on the ground, where the sanderling lays around three eggs. Males defend their territory aggressively.
DISTRIBUTION: Sanderlings breed in the high Arctic around the globe. They migrate for the winter in southern areas around the world. They then form large flocks. Some will visit Hawaii for that season.
Distribution map:
ON PEI: The sanderling is essentially a fall visitor on island beaches on its way further south during its migration. Interestingly, it is only observed ‘accidentally’ in the spring however.
CONSERVATION: Because of their relatively large numbers and widespread population, sanderlings are considered as ‘least concern’. However, their population has declined mainly due to impacts on their feeding habitats during migration.
NOTES: One photo below shows four such sanderlings sleeping on one leg, with one eye open, likely using USWS (unihemispheric slow-wave sleep) as a convenient safety technique. It was a day without wind that allowed them to rest so near the water.
SIMILAR SPECIES: Semipalmated Sandpiper – One way to differentiate it from the semipalmated sandpiper is from the dark color it displays, aside from the white parts – in the sanderling the legs and bill are black and the back and wings are mottled with dark grey, whereas for the semipalmated sandpiper the dark color is brown. Those are the fall colors though. One good way to identify the sanderling is by observing its feeding behavior.
REFERENCES: (New Hampshire PBS) (Norwegian Polar Institute)

Sanderling – Grayton State Park, FL – Mar. 25, 2018 – Roberta Palmer
Sanderling, FL, Roberta Palmer
Four sanderlings sleeping with one eye open – Brackley Beach, PEI – Oct.12, 2015 – © Denise Motard
Sanderlings sleeping, PEINP, Canada
Here is a sanderling running up and down the beach to catch invertebrates while avoiding the waves: