Spotted Sandpiper in breeding (alternate) plumage is nearly unmistakable due to its uniquely (for a shorebird) spotted breast and belly; see Fig. 3, Fig. 5, Fig. 6, Fig. 7, Fig. 8.

Spotted Sandpiper’s back (mantle) in spring and summer (alternate) plumage is brown with a jagged, dark brown crossbar on each feather; see Fig. 3, Fig. 4, Fig. 9.

Spotted Sandpiper flies with stiff, short wingbeats low above the surface of the water along the shore or from rock to rock while calling its characteristic peet-weet alarm.

Walking or standing, Spotted Sandpiper often teeters, bobbing its tail and rump, sometimes incessantly, for a long time.

In all plumages, a bold, pale, broken eye ring and pale eyebrow are characteristic of the bird; see Fig. 3, Fig. 9.

In all plumages, the back (mantle) is brown or grayish brown. The sides of the lower neck and upper breast are brown. A wedge of white separates the brown of the neck and breast from the brown of the folded wings; see Fig. 1, Fig. 11.

The legs are pale: yellow in winter, somewhat pink or orange in breeding plumage; see Fig. 1, Fig. 3, Fig. 8.

The bill is straight, short and two-toned. The base two-thirds is yellow or pinkish and the tip is dark; see Fig. 2.

In flight, the underwings show alternating dark and white bands; see Fig. 6.

The upper wings are gray with narrow, short wing stripes. There are often pale feathers at the front edge, the bend of the wing; see Fig. 5.

The tail projects slightly beyond the folded wings; see Fig. 2. It is gray brown with a dark and light zigzag margin; see Fig. 4.

Winter (basic) plumage is gray brown on the back (mantle). Each mantle feather displays a crisp, dark center shaft; see Fig. 1, Fig. 2.

Winter (basic) adult and juvenile have white underparts; see Fig. 1, Fig. 12.

Winter (basic) adult and juvenile have conspicuously barred wing coverts; the barring consists of dark-pale-dark parallel marks; See Fig. 1, Fig. 2, Fig. 12.

Juvenile back (mantle) feathers are brown with crisp central shafts and dark brown subterminal margins; see Fig. 12.

During migration seasons, Spotted Sandpiper (SPSA) and Solitary Sandpiper (SOSA) are sometimes found in similar habitats. These mostly nonflocking birds often turn up singly at streambanks, riverbanks or wetlands. Both stand or walk with a teeter, the Spotted far more so than the Solitary. Both emit high-pitched double or triple whistles when flushed. For a comparison image, see Fig. 14.

Note the following:

• Spotted Sandpiper looks dumpy with compact dimensions. Solitary Sandpiper is slimmer, longer-necked and longer-legged.
• Spotted Sandpiper flies low over water with short flicks of stiff wings between landing spots. Solitary, when flushed, quickly rises high and flies in a swooping swallow-like fashion with angled wings.
• In breeding (alternate) plumage, Spotted Sandpiper has distinctive dark spots on gleaming white underparts. Solitary Sandpiper’s underparts are always white up to the breast.
• In breeding (alternate) plumage, Spotted has a pinkish-orange bill with a dark tip. The color fades to a darker orange or brownish at other seasons. Solitary’s bill is dull grayish brown or greenish brown, usually paler at the base throughout the year.
• Spotted’s back (mantle) is usually a solid gray brown (winter or basic), with darker brown bars (breeding or alternate) or with dark brown subterminal lines (juvenile). In all plumages, Solitary’s mantle is brown with distinctive pale or white spots.
• Spotted eye ring is often broken; pale and dark lines from the bill extend backward to and behind the eye. Solitary Sandpiper has a bold eye ring and a pale line extending forward from the eye to the bill with a dark line below it.
• In flight, Spotted’s tail is mostly brown with a pale zigzag margin. Solitary’s tail is dark at the center and boldly barred on the edges.
• Spotted Sandpiper in flight has thin white stripes on the upper wings. The underwings have alternate pale and dark lines. In flight, Solitary has brown wings above with no pale stripes and dark gray-brown wings below with some barring.

Spotted Sandpiper (SPSA) and Common Sandpiper (COSA) are sister species that are nearly identical in all but breeding (alternate) plumage. Common Sandpiper is common in palearctic regions of Europe and Asia but would be extremely unusual in New England. Spotted Sandpiper, which is widespread throughout the Western Hemisphere, on the other hand, is often reported in the United Kingdom and the rest of Europe.

Note the following:

• Spotted Sandpiper is heavily and conspicuously spotted on the breast and belly during breeding season (alternate plumage), whereas Common Sandpiper is white on the belly and lower breast, sometimes showing faint dark streaks on the neck or breast.
• Juvenile birds are the most likely to be vagrants; see Fig. 15 for a comparison image of juveniles.
• In all plumages, Common Sandpiper has a longer tail than Spotted.
• Spotted Sandpiper’s bill and legs are usually pale throughout the year. Common Sandpiper’s bill and legs become dusky in fall and winter.
• Spotted has tertial feathers (feathers that cover the primaries when the wings are folded) with plain margins. Common Sandpiper’s tertials have dark-and-light narrow zigzag margins.
• In winter (basic) and juvenile plumage, Common Sandpiper’s facial markings are more subdued than Spotted’s. The eyebrow line (supercilium) is much lighter and more conspicuous and the lower face much paler in Spotted.
• Spotted and Common Sandpiper calls are distinctive. Spotted typically gives a peet-weet or peet-weet-weet call; Common’s calls are much higher pitched, sometimes a continuous series of buzzy, almost raspy, sounds.
• In flight, Common Sandpiper’s white upper wing stripe is thicker and longer, spanning nearly the entire wing. Spotted Sandpiper’s wing stripe is thin and ends short of the body; see Fig. 5, Fig. 13.