11-1-2020 OLIVA PLAJA, VALENCIA - SANDERLING (Calidris alba)

The sanderling, Calidris alba, is a small, dynamic wading bird, easily recognized by its plump form and stout bill. In non-breeding plumage, it presents a very pale, almost white appearance, save for a dark shoulder patch. Come summer, the bird's face and throat adopt a brick-red hue. Juveniles are more striking, with a spangled black and white pattern offering greater contrast.

Adult sanderlings in breeding plumage can be confused with stints due to their size, but their stouter build and thicker bill are distinguishing features. In winter plumage, they might be mistaken for dunlins or red knots. However, the absence of a hind toe and their unique foraging behavior—characterized by a "bicycling" action of the legs—help in identifying them. In flight, a strong white wingbar is visible.

During the breeding season, sanderlings favor the coastal tundra of the High Arctic, often selecting dry, stony areas near wetlands for nesting. In winter and during migration, they are most commonly found on coastal sandy beaches, as well as on tidal sand and mudflats, and less frequently on rocky shores.

Sanderlings breed in the High Arctic regions of North America, Europe, and Asia, including the Canadian Arctic Archipelago, Greenland, Svalbard, and northern Russia. In winter, they are nearly cosmopolitan along the world's marine coasts, migrating long distances from the Arctic to as far as South America, South Europe, Africa, and Australia.

The sanderling (Calidris alba) is a small wading bird. The name derives from Old English sand-yrðling, "sand-ploughman". The genus name is from Ancient Greek: καλίδρις : kalídris or σκαλίδρις : skalídris, a term used by Aristotle for some grey-coloured waterside birds. The species name, alba, is Latin for "white".

It is a circumpolar Arctic breeder, being among the most extreme northern breeding birds in the world, nesting only on the coldest tundra, north of the 5°C July isotherm; in Europe, its southernmost breeding locality is Svalbard, where only a handful (5–15) pairs breed. It is a long-distance migrant, wintering south to South America, western and southern Europe, Africa, and Australia. It is highly gregarious in winter, sometimes forming large flocks on coastal mudflats or sandy beaches.

The sanderling (Calidris alba) is a small, energetic shorebird famous for its characteristic behavior of running back and forth on beaches, trailing the motion of crashing waves. Belonging to the sandpiper family Scolopacidae, it is a long-distance migrant that breeds in the high Arctic tundra and winters on coastal beaches worldwide.

Physical Characteristics

Size: Measures 18–20 cm in length with a 35 cm wingspan, weighing between 40–100 grams.The Three-Toe Distinctiveness: Unique among most sandpipers, it completely lacks a hind toe (hallux). This anatomical adaptation aids its rapid, clockwork-like running style on hard wet sand.

Bill and Legs: Features a short, straight, relatively thick black bill and medium-length black legs.

Winter Plumage: Extremely pale gray above and pure white below, often showing a distinct dark patch at the shoulder bend.

Breeding Plumage: Transforms dramatically into a warm, mottled reddish-brown or brick-red color across the head, neck, and breast.

Global Migration & Habitat

Breeding Grounds: Nest exclusively on the coldest Arctic tundra wetlands across northern North America, Greenland, Svalbard, and Siberia.

Winter Destinations: Journey south to coastal zones across South America, Europe, Africa, Asia, and Australia.

Habitats: Strictly prefer open, sandy marine beaches during non-breeding seasons, though they occasionally utilize mudflats and rocky coastlines during migration.

Diet and Feeding BehaviorSanderlings are highly gregarious and forage in tightly coordinated flocks. They utilize specialized pressure-sensitive receptors at the tip of their bills to locate prey buried in the sand. Their diet primarily consists of:Small marine wormsCrustaceans and amphipodsSmall mollusksInsects (primarily on their Arctic breeding grounds).