Dunlin

(Calidris alpina) (DUNL)

Photographic Identification Guide

Dunlin (Calidris alpina) (DUNL) is a common late fall and winter visitor to southern New England shores. In all plumages, recognize this small sandpiper due to its long, slightly downturned bill, short legs and hunched posture.

In this guide, we cover the features, in order of importance, to look for on these birds. When discussing plumages, we use the terms winter, spring, and summer to refer to northern hemisphere seasons. Because some of these birds spend parts of the year in the northern and southern hemispheres, the correct technical terms for the plumage stages—basic and alternate—help avoid the confusion of seasonal terminology.

visual gallery

species account

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Fig. 21. Comparison of Dunlin and Purple Sandpiper in winter (basic) plumage. Note differences in size, bill and leg colors, bill lengths, back (mantle) colors. Pleasure Bay, South Boston, MA. 31 December 2023.
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Fig. 20. Comparison of Dunlins and Short-billed Dowitchers in flight. Note body size and bill length and shape differences. Forsythe National Wildlife Refuge, NJ. 4 May 2023.
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Fig. 19. Shorebirds in flight. Note white wing stripes of Dunlin vs. gray wings of Stilt Sandpipers and white stripe up back of dowitcher. Forsythe National Wildlife Refuge, NJ. 27 April 2023.
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Fig. 18. Comparison of Dunlin with Short-billed Dowitchers and Stilt Sandpiper. Compare bill lengths and shapes, belly markings and leg colors. Forsythe National Wildlife Refuge, NJ. 26 April 2023.
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Fig. 17. Comparison of Dunlin and Stilt Sandpiper in flight, both in spring (alternate) plumage. Note similarity of bill shape. Forsythe National Wildlife Refuge, NJ. 4 May 2023.
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Fig. 16. Dunlins and Semipalmated Sandpipers in flight. Spring (alternate) plumage. Forsythe National Wildlife Refuge, NJ. 4 May 2023.
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Fig. 15. Comparison of Dunlin and Semipalmated Sandpiper. Note size difference, difference in bill shape and length. Winthrop Beach, Winthrop, MA. 0 October 2017.
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Fig. 14. Comparison of three fall sandpipers: SESA juvenile; DUNL molting from summer (alternate); WRSA molting from summer (alternate). Note very long wings on WRSA. Winthrop Beach, Winthrop, MA. 16 October 2023.
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Fig. 13. Dunlins and Sanderlings in flight. Note long bill and hooded head and breast on Dunlin. Point of Pines, Revere, 20 October 2007.
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Fig. 12. Comparison of Sanderling and Dunlin, both in winter (basic) plumage. Note all white undersides of Sanderling, hooded head and breast and lightly streaked belly of Dunlin. Winthrop Beach, Winthrop, MA. 19 January 2023.
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Fig. 11. Dunlins in flight. Winter (basic) plumage. Note tail and wing pattern, long bill. Forsythe National Wildlife Refuge, NJ. 13 October 2020.
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Fig. 10. Dunlin. Juvenile molting to winter (basic) plumage. Winthrop Beach, Winthrop, MA. 18 September 2016.
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Fig. 9. Dunlin. Summer (alternate) molting to winter (basic) plumage. Winthrop Beach, Winthrop, MA. 1 October 2016.
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Fig. 8. Dunlin. Spring (alternate) plumage. Boston Harbor, MA. 25 May 2022.
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Fig. 7. Dunlins. Spring (alternate) plumage. Snake Island, Winthrop, MA. May 1982.
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Fig. 6. Dunlins. Left: two birds in nearly full spring (alternate) plumage. Right: winter (basic) plumaged bird in delayed molt. Forsythe National Wildlife Refuge, NJ. 4 May 2023.
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Fig. 5. Dunlins roosting. Most are mid-molt from winter (basic) to spring (alternate) plumage. Plymouth Beach, Plymouth, MA. 4 May 2018.
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Fig. 4. Dunlin. Winter (basic) molting to spring (alternate) plumage. Plymouth Beach, Plymouth, MA. 4 May 2018.
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Fig. 3. Dunlins. Winter (basic) molting to spring (alternate) plumage. Bolivar Flats, Port Bolivar, TX. 13 April 2017.
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Fig. 2. Dunlin. Winter (basic) plumage. Charlie's Pasture, Aransas, TX. 24 February 2014.
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Fig. 1. Dunlin. Winter (basic) plumage. Pleasure Bay, South Boston, MA. 25 December 2011.

The photos in this species account are arranged in this order:

Basic: winter plumage, roughly October to April.

DUNL begins its molt to winter (basic) plumage on its sub-Arctic and low Arctic breeding grounds. The molt continues into late fall; full basic plumage is attained by December; see Fig. 1, Fig. 2.

Alternate: first spring and summer after hatch year or adult breeding plumage, April to September.

Beginning in spring, winter (basic) feathers on DUNL are gradually replaced by alternate feathers; see Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8. Replacement of alternate feathers by winter (basic) plumage begins in the fall; see Fig. 9.

Juvenile: young birds, recently hatched, August to October.

These feathers are acquired on the breeding grounds immediately after the natal down is shed and before the young begin their southbound migration. In fall, juvenile feathers begin to be replaced by winter (basic) plumage; see Fig. 10.

Size and weight

There are multiple subspecies of DUNL breeding in circumpolar regions, with three recognized subspecies in North America. The dimensions given below are for Calidris alpina hudsonia, which is the primary migrant through northeast North America. Females are larger and have longer bills.

Body length:

6.5–8.5 in. (16.5–21cm)

Wingspan:

12.7–17.5 in. (32–44 cm)

Bill length:

1.4–1.7 in. (37–44 mm)

Weight:

1.6–2.8 oz. (46–79 g)

Calls

Soft rolling churr when taking flight.

Calls in Delmarva, VA, 2021:

Calls in Humphrey’s County, MS, 2016:

Plumage and other characteristics

In all plumages, DUNL is distinctive because of the very long, downturned bill on a stubby, small shorebird with short legs; see Fig. 1.

Winter (basic) plumage is uniformly gray above with a gray hood over the head, neck and down the upper breast. Faint gray streaks are on lower breast sides and flanks; see Fig. 1, Fig. 2.

In spring, alternate rusty and black feathers begin to replace the winter (basic) feathers. Some black feathers also begin to grow into the belly plumage; see Fig. 3, Fig. 4, Fig. 5.

Full spring (alternate) plumage—in May and later—consists of bright rufous upperparts and crown and a black belly-patch; see Fig. 6, Fig. 7, Fig. 8.

Adults on the breeding grounds stay through summer and into fall. They begin to molt into winter (basic) plumage from mid-summer on. In New England, by the time they arrive in early to mid-October, most are in advanced stages of molt; see Fig. 9.

Newly fledged young birds acquire juvenile plumage that is nearly as colorful as adults: rufous and black mantle feathers, a smattering of black feathers on the belly. They, too, stay near the breeding areas throughout the summer, leaving for fall migration in early October. By then they have molted nearly completely into winter (basic) plumage; see Fig. 10.

In flight, DUNL displays a strong white wing stripe from above and white wings from below. The tail is light gray on the edges and darker gray along the center. In winter (basic) plumage, the throat, neck and upper breast are gray. The long bill is conspicuous; see Fig. 11.

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Breeding range, migration, wintering range, habitat

Three of the ten recognized subspecies of DUNL breed and winter in the western hemisphere, but only one, Calidris alpina hudsonia, occurs with any regularity in New England. The differences among them are mostly confined to dimensions (bill length and body size) and colors of upperparts in breeding plumage.

In North America, DUNL breeds primarily in arctic regions of Canada and Alaska.

DUNL appears along the Canadian Maritimes, New England and central Atlantic coasts by October.

Most Dunlin along the east coast of North America winter between the New Jersey and Florida coasts, but some can be found in small flocks from Massachusetts north to Nova Scotia and New Brunswick.

In spring, the migration route for East Coast Dunlin brings them as far north as the New England coast before they head northwest toward Hudson Bay. They are scarce in the Canadian Maritimes in spring.

In all seasons, DUNL feeds on small crustaceans, mollusks and worms around and near water.

In spring, fall and winter, DUNL is found mostly on sandy beaches or mudflats, feeding rapidly, often in the company of Sanderlings.

At higher tides they roost in dense flocks on higher dunes, salt marshes or salt pans, sometimes on rock jetties or breakwaters.

Similar species

DUNL compared to SAND

Dunlin (DUNL) and Sanderling (SAND) are nearly identical in body size and shape and seek similar habitats to feed in or roost.

Note the following:

DUNL has a dramatically longer bill than SAND and is a brownish gray on the mantle vs. silvery gray of SAND.
In winter (basic) plumage, DUNL throat, neck and upper breast are gray, with fine streaks on the sides of the lower breast and belly. SAND’s underside is pure white from throat to tail; see Fig. 12.
In flight, winter (basic) Dunlins’ long bills and appearance of hooded head, throat and neck make them conspicuous in a flock of mixed shorebirds, especially Sanderlings; see Fig. 13.

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DUNL compared to WRSA

Dunlin (DUNL) is larger than White-rumped Sandpiper (WRSA) and has a much longer bill.

Note the following:

DUNL is round-bodied and chunky; WRSA is long with attenuated wings; see Fig. 14.
In spring and summer (alternate) plumage, DUNL has bright rusty upperparts and a blackish belly; WRSA is grayish on the back (mantle) with some rufous highlights on the upper scapulars; the underparts are white with some streaking.
During southbound migration, few DUNL arrive at New England sites before October. WRSA begin arriving at our beaches in August; some individuals linger into October or later.

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DUNL compared to SESA

Dunlin (DUNL) is much larger than Semipalmated Sandpiper (SESA) and has a much longer bill; see Fig. 15, Fig. 16.

Note the following:

In spring and summer (alternate) plumage, DUNL has bright rusty upperparts; SESA is grayish overall with some brown or rufous highlights on the crown and mantle.
During southbound migration, few Dunlins arrive at New England sites before October. Most SESA are ready to depart or have already departed the region by then.
In winter (basic) plumage, DUNL has a gray hood on the head, upper breast and neck with some fine gray streaks on the lower breast and belly. SESA in late fall is clean breasted with few markings in the center of the neck and upper breast; see Fig. 15.

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DUNL compared to STSA

Dunlin (DUNL) and Stilt Sandpiper (STSA) in flight are among the few small sandpipers in North America with long, downturned bills. For a comparison image, see Fig. 17.

Note the following:

Despite some similarity in bill shape, STSA’s bill is tubular and thick with a blunt tip; DUNL’s bill is far more tapered with a fine tip.
DUNL’s legs are shorter and black; in flight, they barely project beyond the tail. STSA’s legs are very long and yellowish or greenish; in flight the legs project well beyond the tail.
In flight, seen from above, DUNL’s wings have a long white stripe. STSA’s wings are all gray.
DUNL’s tail is white and gray with a bold dark center stripe. STSA’s tail is barred gray at the tip with a white rump.
In spring or summer (alternate) plumage, DUNL’s belly has a black patch. In the same season, STSA has a barred breast and belly.

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DUNL compared to SBDO

Dunlin (DUNL) is much smaller than Short-billed Dowitcher (SBDO) and has a proportionally shorter bill. DUNL has a distinct down-curve to the bill; see Fig. 19.

Note the following:

Spring and summer (alternate) plumage: DUNL has a rusty crown and a speckled rufous and black back (mantle) with a black belly; SBDO has a speckled buffy or cinnamon head, neck and breast; the back (mantle) is speckled brown, black, rusty and white; see Fig. 18.
For in-flight comparisons, see Fig. 19, Fig. 20. DUNL has a dark-centered tail with pale edges, a prominent white wing stripe and, in breeding (alternate) plumage, a black belly. SBDO has a prominent white stripe up the center of the back, pale tips to the rear inner half of the wings (secondary flight feathers) as seen from above and barring along the flanks.

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DUNL compared to REKN

Dunlin (DUNL) is much smaller than Red Knot (REKN). DUNL, however, has a much longer bill.

Note the following:

In spring and summer (alternate) plumage, DUNL has a rusty crown and rufous-and-black mantle with a black belly; See Fig. 8. REKN has a smooth cinnamon head, neck, breast and belly; see REKN Fig. 4.
In the fall, although both DUNL and REKN are grayish, the distinctive patterned look of REKN’s back (mantle) feathers with their subterminal dark lines stands out; see REKN Fig. 11.
Though much reduced in numbers in recent years, fall migrant Red Knots arrive in coastal New England (primarily Monomoy Island off Cape Cod) in mid-July and remain into early fall. Dunlin do not appear in New England in any numbers until October.
DUNL bill is curved, tapered and distinctly longer than the head; See Fig. 1. REKN bill is sturdy and straight, barely as long as the head; See REKN Fig. 1.

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DUNL compared to PUSA

Purple Sandpiper (PUSA) is slightly larger and chunkier than Dunlin (DUNL). At high tide, they often roost together on rocks. At lower tides, DUNL prefers sandy beaches and PUSA forages on offshore rocks. Most of the features discussed below are shown in Fig. 21.

In winter, when the two species are likeliest to roost together, DUNL’s mantle is gray-brown; PUSA has a dark slaty back (mantle).
Both species have long, slightly curved bills. Dunlin’s black bill is slimmer and longer than the pale-based PUSA bill.
In spring and summer (alternate) plumage, DUNL has bright rusty upperparts; PUSA is dark gray with rufous or coppery flecks on the back (mantle).

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