Curlew Sandpiper Calidris ferruginea Scientific name definitions

Steven G. Mlodinow and Fernando Medrano
Version: 2.0 — Published May 19, 2023

Photos from this Account

Breeding adult
Nonbreeding adult
Juvenile
Nonbreeding adult
Molting adult
Alternate lateral view.

In Alternate plumage, it is largely colored brick-red but has a white vent and undertail coverts; the crown is streaked with black.

Alternate dorsal view.

Wing-coverts are grayish, and that the back and scapulars are mottled reddish, black and white.

Alternate frontal view.
Basic lateral view.

In Basic plumage, the upperparts are pale grayish brown with fine brown streaking; lores and auriculars are grayish brown, contrasting markedly with the white supercilium.

Basic frontal view.

Underparts are white and unmarked, except for the chest, which has fine dark-brown streaking and is variably washed with pale brown.

Basic dorsal view.
Juvenile lateral view.

In Juvenile plumage, the upperpart feathers are gray-brown, except for a darker brown central shaft streak and subterminal band, plus a crisp white or pale buff fringe, which combined produce a scaly appearance.

Juvenile frontal view.

Underparts are largely white with limited fine streaking on chest, and in fresh plumage, a buff wash on the chest; face is well-patterned, with a white supercilium that contrasts markedly with a dark-brown loral stripe and a diffuse brown auriuclar patch.

Juvenile dorsal view.
Curlew Sandpiper in flight.
Curlew Sandpiper.

Alternate plumage.

Possible confusion species: Red Knot (Calidris canutus).

The Red Knot is larger, has a shorter and stouter straight bill and proportionately shorter greenish legs.

Possible confusion species: Red Knot (Calidris canutus).

Red Knot in flight has its rump mottled grayish rather than white.

Curlew Sandpiper.

Alternate plumage.

Possible confusion species: Red Phalarope (Phalaropus fulicarius).

Red Phalarope in alternate plumage has a much shorter bill that is straight and yellow, plus a white face, black crown, and brick-red underparts that extend through the undertail coverts.

Possible confusion species: Red Phalarope (Phalaropus fulicarius).

In flight Red Phalarope in alternate plumage has a bolder wing stripe and little to no white on the rump.

Curlew Sandpiper.

Basic Plumage.

Possible confusion species: Stilt Sandpiper (Calidris himantopus).

In Juvenile and Basic Plumages, Stilt Sandpiper has longer green legs, straighter-based and blunter tipped bill and flatter head.

Possible confusion species: Stilt Sandpiper (Calidris himantopus).

In flight, Stilt Sandpiper lacks an obvious wing stripe and its legs project well beyond the tail.

Curlew Sandpiper.

Basic plumage.

Possible confusion species: Dunlin (Calidris alpina).

Dunlin in Basic plumage has a comparatively plain head with a less distinct supercilium, a stouter and less evenly curved bill.

Possible confusion species: Dunlin (Calidris alpina).

In flight, Dunlin in Basic plumage has a blackish line that bisects the white rump.

Curlew Sandpiper.

Juvenile plumage.

Possible confusion species: Dunlin (Calidris alpina).

Dunlin in Juvenile plumage has blackish-brown spots on the sides of the upper belly and rusty markings on the mantle.

Possible confusion species: Dunlin (Calidris alpina).

In flight Dunlin in Juvenile plumage shows rusty markings on the mantle.

Juvenile Curlew Sandpiper.

Fresh juveniles can show tawny to warm buff breasts, with indistinct streaking to the sides. Note also the pattern to the upperpart feathers, gray with black anchor-shaped markings and wide pale fringes creating a scaly appearance.

Juvenile Curlew Sandpiper

Upperpart feathers and upperwing coverts are gray with black anchor-shaped markings and wide pale fringes creating a scaly appearance. Primary tips are narrower than in later plumages.

Juvenile Curlew Sandpipers.

Body and wing feathers are uniformly juvenile and fresh in September as compared with older birds. Juvenile primaries and rectrices are narrower than formative and basic feathers.

Curlew Sandpiper undergoing Preformative Molt.

Most body feathering is formative whereas remiges and rectrices are juvenile, except for the tertials which are contrastingly fresh, gray, and formative. The upperwing greater and primary coverts are juvenile and the median coverts are mixed formative (inner) and juvenile (outer). This bird likely will replace more wing coverts and perhaps outer primaries and inner secondaries in December–March on the winter grounds.

Formative Curlew Sandpiper.

Note the mixed formative and juvenile upperwing coverts, the juvenile outer median and greater coverts retained, brownish, and worn, contrasting with the replaced inner and lesser coverts. Four or five tertials have been replaced whereas the rest of the remiges and the rectrices are juvenile, relatively narrow and tapered at the tips, and not showing molt clines.

Formative Curlew Sandpiper.

This individual has replaced the outer 4–5 primaries and inner 8–9 secondaries in during an eccentric preformative molt; note the block of retained juvenile inner primaries and outer secondaries. The rectrices appear to be replaced. Some but not all Curlew Sandpipers replace outer primaries during the preformative molt.

First Alternate Curlew Sandpiper (right) with Definitive Alternate individuals (female center-front and male in back).

For some individuals, particularly those that remain on winter grounds for first summer, the first prealternate molt can be absent or involved a few feathers that may resemble non-breeding rather than breeding appearance. In the bird on the right, just a few inner scapulars appear to be replaced with only partial breeding appearance.

First Alternate Curlew Sandpiper

First alternate plumage is variable in this species, ranging from fully non-breeding in appearance to almost fully breeding in appearance. Here a few back and underpart feathers are alternate, whereas wing coverts are mixed formative and juvenile as in formative plumage.

First Alternate Curlew Sandpiper

Some individuals can attain near-full breeding appearance. Note the frayed and worn retained juvenile greater coverts and outer primaries.

Curlew Sandpiper undergoing Definitive Prebasic Molt.

The definitive prebasic molt can be suspended and protracted., in many individuals commencing on the breeding grounds, continuing at stopover sites, and completing on winter grounds. Body plumage is usually replaced in October–November while flight feather molt completes in January–April. In this individual molt of basic body feathering and upperwing secondary coverts has nearly completed whereas molt of flight feathers is ongoing in typical sequence. The broader and squared, unmolted outer secondaries and rectrices indicate the Definitive Prebasic Molt as opposed to the Second Prebasic Molt.

Definitive Basic Curlew Sandpiper.

Fresh definitive basic plumage is primarily gray and white. The basic feathers of the upperparts can show mixed levels of wear following suspended and/or protracted molts. The broad and blackish outer primaries and rectrices indicate definitive basic as opposed to formative plumage.

Definitive Basic Curlew Sandpiper.

Once the definitive prebasic molt has completed the upperwing coverts lack molt clines and the flight feathers are uniformly broad, blackish, and relatively fresh compared to retained juvenile feathers of formative plumage. Note also the molt clines from more worn innermost primary (p1) to fresher and darker outer primary (p10) and more worn outermost secondary (s1) to fresher and darker s4. Body feathering becomes browner in appearance with wear.

Definitive Alternate female Curlew Sandpiper.

Breeding appearance is variable in females but typically mottled gray, black and rufous above and mottled reddish and white below. Extent of reddish appearance varies from almost none to almost as full as duller definitive alternate males. Here the dusky primary tips, basic upperwing coverts, and fuller breeding appearance for a female indicate definitive as opposed to first alternate plumage.

Definitive Alternate male Curlew Sandpiper.

Definitive alternate males have more extensive reddish and less whitish to the sides of the head and underparts than definitive alternate females. When fresher in April and May, the underpart feathers can be fringed white. The black primary tips, basic upperwing coverts, and fuller breeding appearance indicate definitive as opposed to first alternate plumage.

Adult Curlew Sandpiper. 

The bill is black, the iris is dark brown, and the legs and feet are black, grayish black, or black with an olive tinge.

Curlew Sandpiper winters in Thailand; January, Samut Sakhon, Thailand.
Curlew Sandpiper is a regular vagrant to California, United States.
Immatures remain at or near their non-breeding locations during their first year of life; June, Victoria, Australia.
Some Curlew Sandpipers reach West Africa by following the Moroccan coast.
Mudflats and estuaries surrounding the Yellow Sea have an important role for birds wintering in southeast Asia and Australasia during both migratory periods; April, Hebei, China.
Bird capturing a prey.
Bird feeding on mollusk.
Scratching its head and neck with its foot.
Using the bill to preen its breast.
The decline of intertidal habitat in the Yellow Sea region of the East Asian–Australasian Flyway is thought to be driving this species' decline.

Macaulay Library Photos for Curlew Sandpiper

Top-rated photos submitted to the Macaulay Library via eBird. Note: Our content editors have not confirmed the species identification for these photos.

Recommended Citation

Mlodinow, S. G. and F. Medrano (2023). Curlew Sandpiper (Calidris ferruginea), version 2.0. In Birds of the World (N. D. Sly, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.cursan.02
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