Sanderling

About

The Sanderling is a small, plump, pale shorebird, well-known for its distinctive behavior of running along the water's edge on sandy beaches, chasing receding waves and fleeing incoming ones. It is a highly migratory species, breeding in the high Arctic and wintering on coasts worldwide, making it one of the most widespread shorebirds.

Size & lifespan

Length

18-21 cm (7.1-8.3 in)

Wingspan

35-40 cm (13.8-15.7 in)

Weight

40-100 g (1.4-3.5 oz)

Lifespan

Up to 13 years in the wild

Diet

Carnivore (primarily invertebrates)

Physical characteristics

Plumage

Non-breeding (winter) plumage is very pale, almost entirely white underneath with a pale grey back and dark shoulder patch (carpal bar). Breeding plumage features rufous (reddish-brown) on the head, neck, and breast, with dark mottling on the back. The belly remains white.

Beak shape

Relatively short, straight, and stout black bill.

Eye color

Dark brown.

Leg color

Black legs and feet. Notably, Sanderlings lack a hind toe, which is unique among most shorebirds and aids in their rapid movement on sand.

Distinguishing features

Its pale, 'bleached-out' appearance in winter, prominent dark carpal bar, and characteristic 'wave-chasing' behavior are key. The lack of a hind toe is a unique anatomical feature, though not easily observed in the field.

Juvenile appearance

Juveniles resemble non-breeding adults but have a more scaly or checkered pattern on their back due to dark feather centers with pale fringes. They also show a more distinct dark carpal bar.

Seasonal changes

Dramatic change from the pale grey and white non-breeding plumage to the rufous and mottled breeding plumage. The rufous coloration is most intense on the head, neck, and upper breast during the breeding season.

Sexual dimorphism

Males and females are generally similar in appearance, though females may be slightly larger and have less extensive rufous coloration in breeding plumage.

How to identify

1. 1

   Plumage (Non-breeding)

   Look for a very pale, almost white bird with a pale grey back and a distinct dark patch on the bend of the wing (carpal bar). The underparts are pure white.

2. 2

   Plumage (Breeding)

   Observe the reddish-brown (rufous) coloration on the head, neck, and breast, with dark mottling on the back. The belly remains white.

3. 3

   Behavior

   Watch for its characteristic 'wave-chasing' behavior, running rapidly along the water's edge on sandy beaches, probing for food.

4. 4

   Size and Shape

   A small, plump sandpiper with a relatively short, stout black bill and black legs. It appears 'neckless' and compact.

5. 5

   Flight

   Note its swift, direct flight, often in tight, synchronized flocks, especially during migration.

Habitat & range

Biomes

Tundra (breeding), coastal beaches, mudflats, estuaries, and rocky shores (non-breeding).

Geographic range

Breeds in the high Arctic regions of North America, Europe, and Asia. Migrates to coastal areas worldwide, including North and South America, Europe, Africa, Asia, and Australia. It is one of the most widely distributed shorebirds.

Elevation range

Primarily sea level, occasionally found inland during migration near large bodies of water.

Preferred environments

Sandy beaches, especially those with gentle slopes and abundant wave action, are preferred during migration and winter. Also uses mudflats and rocky intertidal zones.

Behavior

Activity time

Diurnal, but can also feed at night, especially on moonlit nights or when tides are favorable.

Feeding habits

Feeds primarily on small marine invertebrates, especially crustaceans (e.g., amphipods, isopods) and polychaete worms, which it extracts from the sand or mud with its bill. It employs a characteristic 'run-stop-probe' feeding strategy, often chasing receding waves to snatch prey exposed by the water.

Social behavior

Highly social, especially outside the breeding season. Forms large, dense flocks on migration and in wintering areas, often associating with other small shorebirds. On breeding grounds, they are more solitary or found in loose pairs.

Flight pattern

Flight is swift and direct, often in tight, synchronized flocks during migration. When disturbed, they fly low over the water or sand.

Migration pattern

Long-distance migrant. Breeds in the high Arctic and undertakes one of the longest migrations of any bird, traveling to temperate and tropical coasts globally. Migration occurs in spring (April-May) and autumn (July-October).

Territoriality

On breeding grounds, males establish small territories. During migration and winter, they are not territorial, feeding communally in flocks.

Breeding & reproduction

Breeding season

June to August.

Nesting habits

Nests are shallow scrapes on the ground in dry, stony tundra, often lined with leaves, moss, or lichen. Typically located on elevated, well-drained sites.

Clutch size

Usually 4 eggs.

Egg description

Typically 4 eggs, olive to buff-colored with dark brown spots and blotches, concentrated at the larger end.

Incubation period

23-24 days.

Fledging period

Approximately 17-21 days after hatching, chicks are precocial and able to feed themselves shortly after hatching.

Parental care

Both parents incubate the eggs, but often one parent (usually the female) departs after hatching, leaving the male to care for the chicks. In some cases, both parents may raise the brood, or the female may lay a second clutch with another male.

Where to find

Field tips

1. Scan the water's edge. Sanderlings are almost always found right at the interface of land and water, actively feeding. Use binoculars to scan this zone.
2. Observe behavior. Their distinctive 'wave-chasing' feeding behavior is a strong identification clue. They run with the waves, probing quickly.
3. Look for flocks. Outside of the breeding season, Sanderlings are highly social and often found in flocks, sometimes mixed with other small shorebirds.
4. Check for plumage. In winter, their very pale, almost white appearance with the dark carpal bar is unmistakable. In summer, look for the rufous wash.

Similar species

Quick facts

Global Distribution:

One of the most widespread shorebirds, breeding in the Arctic and wintering on coasts worldwide.

Unique Feature:

Lacks a hind toe, which is thought to aid in its rapid movement on sandy substrates.

Feeding Strategy:

Known for its 'wave-chasing' behavior, running back and forth with the tide to find food.

Plumage Change:

Undergoes a dramatic plumage change from pale grey/white in winter to rufous/mottled in summer.

Fun facts

• Sanderlings undertake one of the longest migratory journeys of any bird, traveling from the high Arctic to the southern tips of continents.
• They are often seen in large, synchronized flocks, performing aerial maneuvers that appear to flash white and dark as they turn.
• The Sanderling's scientific name, 'Calidris alba', means 'white sandpiper', referring to its pale winter plumage.
• Despite their small size, Sanderlings are incredibly hardy and adapted to extreme Arctic breeding conditions.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Charadriiformes

Family

Scolopacidae

Genus

Calidris

Species

Calidris alba

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