Shorebird Identification: Size, Bill, Legs and Behavior

To identify a shorebird, judge its size, then its bill, then its leg color, then how it feeds, and only then the plumage. Bird Observer's New England Shorebird Guide says size, shape and behavior are often as helpful as plumage, because many species share the same gray-brown winter colors.

• Size: compare it with a bird you know. The Pacific Flyway Shorebird Survey slides give lengths from 4.75 in (Least Sandpiper) to 19 in (Long-billed Curlew).
• Bill: short and thick (plovers), straight and long (dowitchers), slightly upturned (Greater Yellowlegs), drooping at the tip (Western Sandpiper, Dunlin) or long and curved down (curlews, Whimbrel).
• Legs: yellow, black, gray, blue-gray, orange or flesh-colored. The survey warns that mud can stain legs, so look at more than one bird.
• Behavior: Bird Observer says plovers run, stop suddenly and pull up food, while yellowlegs and their relatives teeter as they walk and prefer shallow water. The survey calls Sanderlings wave chasers.

The Pacific Flyway Shorebird Survey slides give these three:

• Long-billed Curlew: 19 in, the largest North American shorebird, with a very long down-curved bill, gray legs, cinnamon underparts and cinnamon underwings.
• Whimbrel: 14 in, long down-curved bill, dark short legs, and a head striped brown and white. Next to a curlew it is smaller, shorter-billed and darker-legged, with the striped head.
• Marbled Godwit: 16 in, a very long two-colored bill that curves slightly up, long dark legs and cinnamon wing linings.

The bill direction is the quick test: down-curved means curlew or Whimbrel, slightly upturned means godwit.

• Killdeer: 8 in, brown above and white below, with two black breast bands and a red eye ring; flesh-colored legs (Pacific Flyway Shorebird Survey).
• Semipalmated Plover: 5.75 in, a single black neck band, orange to yellow legs and a short two-colored bill.
• Snowy Plover: 6.25 in, pale above, with a broken breast band and gray legs.
• Black-bellied Plover: 9.5 in and plump, gray above with a short thick bill and black legs. In flight it shows black axillaries (the armpits), a white wing stripe and a white rump.

Count the breast bands first: two is a Killdeer, one is a Semipalmated Plover, a broken one is a Snowy Plover.

• Greater vs Lesser Yellowlegs: both have bright yellow legs. The Greater is 14 in with a longer, slightly upturned bill and a "tew, tew, tew" call; the Lesser is 10.5 in with a shorter, straighter bill and a "too-too" call (Pacific Flyway Shorebird Survey). The call is a second check when the bill is hard to judge.
• Willet: 13.5 in, plain gray and plump, with blue-gray legs and a long, thick, straight bill. It looks dull until it flies and shows a bold black-and-white wing pattern.
• Dowitchers: about 10 in, with a long straight bill, dull yellowish legs, a white wedge up the back in flight and a tail barred black and white. Indiana Audubon separates the two species in fall: the Short-billed has a distinct kink just before the bill tip and is sleeker, and its wingtips stop before the tail; the Long-billed has a straighter bill, looks bulkier, and its wingtips reach barely past the tail. Bird Observer says Long-billed is extremely scarce in spring in New England but expected in small numbers in fall.

"Peeps" are the smallest sandpipers, and leg color separates the common ones:

• Least Sandpiper: the smallest, browner, with a short, thin, slightly down-curved bill and yellowish legs (Pacific Flyway Shorebird Survey). Flathead Audubon says it prefers grassy edges.
• Semipalmated Sandpiper: slightly larger than the Least, with black legs and a tubular-looking straight bill that is noticeably thicker (Flathead Audubon).
• Western Sandpiper: 5.25 in, black legs and a longer bill that is thicker at the base and droops at the tip. Indiana Audubon says fall juveniles show bright rufous upper scapulars (shoulder feathers), while young Semipalmated are dull brown. The survey calls it perhaps the palest peep in winter.
• Dunlin: 7 in, black legs, a medium drooping bill, gray upperparts and a white belly in winter (Pacific Flyway Shorebird Survey).
• Sanderling: 6.5 in, black legs, very pale gray above with a wide white wing stripe; it runs in and out with the waves.
• Red Knot: 9-9.8 in, stout olive-yellow legs and a short straight black bill, the largest of this group.

The survey adds a caution: mud can make a Least Sandpiper's yellow legs look dark, so check the bill and color too.

Bird Observer's guide gives the New England calendar: American Woodcock arrives in February, Killdeer and Wilson's Snipe in March, and most species in May, with the main movement in the last week of May or the first week of June. Fall migration starts in early July with adult females, then males in mid-August and juveniles in September; by November most species are far to the south.

That timing explains the plumage you see. The guide shows breeding, winter (basic) and juvenile plumages plus in-between stages. Birds passing in July and August are adults; from September, many are juveniles, which Indiana Audubon uses to separate species such as Western and Semipalmated Sandpipers. Western Sandpiper, like the Long-billed Dowitcher, is extremely scarce in New England in spring but expected in small numbers in fall.

Leg color and bill shape are the main clues on this page, so a photo has to show both. Before you walk closer, take:

• A side-on frame with the legs above the waterline, since leg color splits the peeps.
• The bill in profile, to see a droop, a kink or an upturn.
• A second bird of known size in the same frame, such as a Killdeer or a gull, because size is hard to judge on open mud.
• A flight shot if it flushes: wing stripes, a white rump or a white back wedge separate Black-bellied Plover, Willet and dowitchers.

BirdLens suggests the species from a photo. For the larger waders on the same mudflats, see Great Blue Heron feather identification; for the ducks alongside them, see the duck identification chart.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. If you find an error, tell us and we will correct it.