Purple Sandpiper

(Calidris maritima) (PUSA)

Photographic Identification Guide

Purple Sandpiper (Calidris maritima) (PUSA) is a familiar winter visitor to rocky, wave-washed New England shores, particularly along the Maine coast. It is Holarctic; it breeds near the shores of the entire Arctic Ocean, though in scattered pockets. The eastern North America breeding population of PUSA is, unfortunately, declining.

In all plumages, recognize this small sandpiper by its dark, hooded plumage; long, slightly downturned bill; short, pale-colored legs and hunched posture.

In this guide, we cover the features, in order of importance, to look for on these birds.

visual gallery

species account

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Fig. 16. Comparison of Purple Sandpiper and Dunlin 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. 15. Purple Sandpipers. In winter, juveniles maintain pale margins on back (mantle) feathers. Rockport, MA. 9 March 2018.
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Fig. 14. Purple Sandpiper. Details of upper wing and tail pattern. Pleasure Bay, South Boston, MA. 8 February 2023.
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Fig. 13. Purple Sandpipers. In late fall and winter, juveniles display narrow white margins on back (mantle) feathers. Pleasure Bay, South Boston, MA. 27 November 2011.
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Fig. 12. Purple Sandpiper. Recently fledged juvenile. Note fresh pale margins to back (mantle) feathers. Svalbard, Norway. 7 August 2007.
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Fig. 11. Purple Sandpiper. Spring (alternate) plumage with coppery-golden margins on back (mantle) feathers. Finnmark, Norway. 14 June 2023.
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Fig. 10. Purple Sandpipers. In flight, dark tail and white inner wing line with pale outer wing panel are distinctive. Baffin Island, Canada. 6 June 2019.
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Fig. 9. Purple Sandpiper. In flight, white inner wing line expands to pale outer wing panel. Svalbard, Norway. 2 July 2023.
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Fig. 8. Purple Sandpiper. Spring (alternate) plumage. Note facial, breast and belly pattern. Finnmark, Norway. 3 June 2023.
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Fig. 7. Purple Sandpiper. Spring (alternate) plumage. Svalbard, Norway. 17 June 2023.
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Fig. 6. Purple Sandpipers. Molting migrants acquiring spring (alternate) plumage. Boston Harbor Islands, MA. 18 May 2023.
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Fig 5. Purple Sandpiper. Molting to spring (alternate) plumage. Nahant-Lynn Beach, MA. 25 May 2008.
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Fig. 4. Purple Sandpiper. Winter (basic) plumage. Even in late winter, some young birds continue to show broad pale margins to their back (mantle) feathers. Rockport, MA. 9 March 2019.
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Fig. 3. Purple Sandpipers in flight. Winter (basic) plumage. Note hooded appearance, orange base to bill. Pleasure Bay, South Boston, MA. 31 December 2023.
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Fig. 2. Purple Sandpipers. Winter (basic) birds roosting. Note dark hood, subdued facial pattern, pale legs, pale base to long bill. Rockport, MA. 1 February 2018.
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Fig. 1. Purple Sandpiper. Winter (basic) plumage. Note unpatterned gray-brown face. Pleasure Bay, South Boston, MA. 8 February 2023.

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

Basic: winter plumage, plumage, roughly December to March.

PUSA begins its molt to winter (basic) plumage on its Arctic breeding grounds. Full basic plumage is attained by December; see Fig. 1, Fig. 2, Fig. 4.

Alternate: first spring and summer after hatch year or adult breeding plumage, mid-March to late June.

Beginning in spring, winter (basic) feathers on PUSA are replaced by alternate feathers; see Fig. 5, Fig. 6, Fig. 7, Fig 8, Fig. 11.

Juvenile: young birds, recently hatched, July to September.

These feathers are acquired on the breeding grounds immediately after the natal down is shed and before the young begin their southbound migration; see Fig. 12. In late summer, juvenile feathers are replaced by winter (basic) plumage.

Size and weight

There are several populations of PUSA breeding in circumpolar regions. The dimensions given below are for individuals breeding in Canada; these are the primary migrants and winter residents in northeast North America. Females are larger and have longer bills.

Body length:

8–8.75 in. (20–22 cm)

Wingspan:

16.75–18.5 in. (43–47 cm)

Bill length:

1.1–1.5 in. (28–37 mm)

Weight:

1.8–3.7 oz. (52–105 g)

Calls

Males sing a distinctive loud song in flight over the breeding territory. In winter, most calls are a hoarse churring.

Song in Sorsele, Sweden, June 2016:

Calls in Tromsø, Norway, September 2020:

Plumage and other characteristics

PUSA bill is moderately long and slightly downturned.

In winter (basic) plumage, PUSA’s legs and base of bill are orange or yellow; see Fig. 1.

In spring and summer (alternate) plumaged birds, the legs and base of the bill become darker but still display some orange or yellow; see Fig. 5, Fig. 7, Fig. 11.

Winter (basic) plumage is dark purplish-brown or dark gray on the back (mantle) with a smoky hood over the head, neck and down the upper breast. Heavy, broad gray streaks mark the pale lower breast, belly and flanks; see Fig. 1, Fig. 2, Fig. 4.

In spring, the back (mantle) feathers begin to be replaced by dark brown feathers with broad white, rusty or copper-colored margins; see Fig. 5, Fig. 7.

Full spring (alternate) plumage in June and July consists of dark brown upperparts heavily marked with copper-colored margins. Underparts are pale with intricate brown markings. An angled dark brown ear-patch decorates the face; see Fig 8, Fig. 11.

Adults in summer (alternate) plumage begin to molt to winter (basic) plumage in July and complete the molt by mid-September.

Newly fledged young birds acquire juvenile plumage that is scaly, as do many young shorebirds. The gray feathers on the lower back (mantle) are bordered by broad white margins. On the upper back (scapular region) the pale feather margins are buffy; see Fig. 12.

In flight, in all plumages, PUSA is dark above, hooded on the head and breast, pale on the belly, with a mostly dark tail. A strong pale inner wing line broadens to a whitish panel on the outer wing; see Fig. 3, Fig. 9, Fig. 10, Fig. 14.

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Breeding range, migration, wintering range, habitat

Purple Sandpiper (PUSA) breeds in disjunct locations scattered across arctic regions of the world. The center of the breeding population is in Svalbard Island, Norway, and Iceland. In North America, PUSA nests on northeastern Canadian arctic islands north of Hudson Bay.

Nesting areas in the Arctic range from rocky, mossy or tundra sites at sea level to areas that are thousands of feet above sea level close to ice and snow.

The wintering range of PUSA is the farthest north of any shorebird species. In North America, PUSA winters from the southern coast of Newfoundland south to the Carolina coasts. At all seasons, PUSA feeds on small crustaceans, mollusks and worms around and near water.

In summer, they eat many insects and spiders as well as some vegetation, including algae, seeds, berries, leaves and buds.

In winter in high latitudes, PUSA feeds primarily on mollusks, which are common and do not become inactive in cold weather. PUSA swallows small mollusks (and other hard-shelled prey) whole and crushes the shells in the gizzard.

Wintering habitat is along the ocean on wave-washed rocky shores, breakwaters and jetties.

During migration, PUSA seeks out rocky habitat similar to its wintering areas but can occasionally be found on sandy beaches; see Fig. 5.

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Similar species

PUSA compared to SAND

Purple Sandpiper (PUSA) is slightly larger and chunkier than Sanderling (SAND). At high tide, they often roost together on rocks. At lower tides, SAND prefers sandy beaches and PUSA forages on offshore rocks.

Note the following:

In winter, when the two species are likeliest to roost together, PUSA has the darkest back (mantle) of the shorebirds; SAND has the palest.
PUSA has a long, slightly curved bill compared to the straight, short bill of SAND. PUSA’s bill is pale yellow-orange at base.
PUSA’s legs are always pale, often yellow-orange. SAND’s legs are black.
In flight, PUSA’s appearance with its dark-hooded head, throat and neck makes it conspicuous in a flock of mixed shorebirds, especially compared to the much paler SAND.

PUSA compared to DUNL

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. 16.

In winter, when the two species are likeliest to roost together, PUSA has a dark slaty back (mantle); DUNL’s mantle is gray-brown.
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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