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Catoptrophorus semipalmatus - Willet

Willet image

Geographic range:

Southwestern Canada to Peru; Nova Scotia to French Guiana

Key features:

White wing patches seen in flight, and a loud and piercing call.

Similar species:

Tringa melanoleuca -- Greater Yellowlegs


bay (rocky shore), bay (sandy shore), estuary, exposed rocky shore, exposed sandy beaches, protected rocky shore, protected sandy beaches

Primary common name:


Synonymous name(s):

Tringa semipalmata

General grouping:

Seabirds and shorebirds

ITIS code:


Geographic Range

Range Description:

Western Willets breed around freshwater ponds and prairie marshes from southwestern Canada, the Great Plains of North America, to California, Nevada, Colorado and south to Mexico. In winter they migrate to the coasts of Oregon and California (including the Salton Sea), and south to Peru. Eastern Willets breed in coastal salt marshes from Nova Scotia to Florida, Mexico, and the Caribbean. In winter they migrate to the Carolinas, Peru and French Guiana on the Atlantic coast. In the MBNMS area the Willet is a common migrant and winter resident.


bay (rocky shore), bay (sandy shore), estuary, exposed rocky shore, exposed sandy beaches, protected rocky shore, protected sandy beaches


Relative abundance:

Common, particularly in winter

Species Description

General description:

There are two subspecies of Willets: Western Willet, Catoptrophorus semipalmatus inornata, and Eastern Willet, Catoptrophorus semipalmatus semipalmatus. Western Willets breed in freshwater habitats and are slightly larger and paler gray. Eastern Willets have stouter bills and more barring on their chest and back. There is a slight difference in the pitch of their calls, but it is very difficult to detect. The Willet is a large (pigeon sized), fairly plump sandpiper and both sexes look alike, with the female being slightly larger. Adults have long, gray legs and a long (6.5 cm/2.59 in), fairly thick bill that is black at the tip and gray-green at the base. In breeding plumage the body is a mottled gray-brown above and lightly streaked and barred underneath. The rump is white with a dark band at the end of the tail. On the ground they look fairly nondescript, but in flight the bright black and white patterning on the wings, called flash marks, is striking and distinctive. In the winter the plumage is plain gray-brown above and white below. The immature Willet is similar to the adult, but more brownish and its back feathers have lighter edges. If one Willet takes flight, all others will join it, flying together a short distance, calling back and forth. The flight of the Willet is short and low, with alternating rapid wing beats and then glides. Their call is a piercing “pill-will-willet” in flight, and upon landing again further down the beach, a quieter “kuk-kuk-kuk-kuk-kuk”. It is the only North American sandpiper whose breeding range extends southward into the tropics

Distinctive features:

Large gray-brown sandpiper with long, gray legs; a 2.5 inch long, sturdy, black bill fading to gray-green at the base; white wing patches, known as flash marks, seen only in flight; piercing loud call given when in flight. Other birds have white wing patches, but those of the Willet are most pronounced and distinctive. If a predator were to attack a single Willet in a flock on the ground, the surprising display of the white flash marks as the flock took flight, would so startle the predator that the entire flock could escape.


Length: 33-41 cm (13-16 in) Wingspan: 70 cm (28 in) Weight: 200-330 g (7.06-11.65 oz)

Natural History

General natural history:

The Willet is monogamous, with strong fidelity to its mate and is usually a solitary ground nester, although they are also known to be semi-colonial, especially along the Atlantic coast. They begin to breed when they are two years old, on coastal beaches, coastal lagoons, mud banks, freshwater and salt marshes, lake shores, and wet prairies. Courtship includes bowing by the male and flashing of the prominent white and black wings at the nest site. The female chooses the nest site and work on the nest continues until the eggs are laid.

They maintain separate feeding and nesting territories, are very territorial and will aggressively defend their nest and feeding territory. They will circle low or go to treetops or other perches to call loudly until the perceived threat retreats. They will continue to protect their territory by following the intruder for some distance.

The nest may be conspicuous and elaborate but is usually well hidden in a depression about 16 cm (6.5 in) in diameter, on open ground, lined with dry vegetable matter, and concealed among low-growing bushes or in a clump of grass. Usually 4 olive or buff colored eggs, thickly spotted with chocolate brown and 53 mm (2.1 in) long, are laid. Both parents incubate the eggs for from 22 to 29 days. The male incubates the eggs at night. The chicks are precocial, leaving the nest within one day of hatching. They are led by both parents to feeding areas away from the nest to find their own food. Two to three weeks after the hatching of the chicks the female abandons her mate and the brood. The male attends the brood for one or two more weeks. They will pick and probe, wade up to their belly, and will also swim while learning to forage for food. The male parent leaves the breeding grounds when the chicks are about 4 weeks old, just before the young fledge at about 28 days. A second clutch of eggs is produced if the first is destroyed.

The adults depart the breeding grounds in June and July, with the juveniles following by August, to wintering grounds in the southern U.S. to central South America and the West Indies. Willets stay on their wintering grounds until March/April, when they migrate back to their breeding grounds. They maintain a strong fidelity to their feeding territory. Non-breeders feed day or night during ebb, low, and flood tides in coastal estuaries with extensive intertidal mudflats. During high tide they roost nearby in saline emergent wetlands, salt ponds, dikes, or upland fields. On non-tidal shores, feeding may be primarily diurnal. They may fly several miles between feeding grounds and high tide roosts.

A group of sandpipers may be called a “bind”, “contradiction”, “fling”, “hill”, or a “time-step” of sandpipers! Along the central coast, non-breeding Willets do not migrate to breeding territories in the spring. Monterey Bay residents remain to summer around Elkhorn Slough and nearby river mouths.


Red foxes, coyotes, raccoons, birds of prey, crows and human visitation, which may attract other mammalian predators.


Aquatic insects and larvae, crustaceans, mollusks, marine worms, small fishes and plant material.

Feeding behavior

Carnivore, Omnivore

Feeding behavior notes:

Willets forage on mudflats, beaches, or in shallow water, probing or picking up food by sight. They separate when feeding but remain in loose contact. If one bird takes flight, all the others will join it, flying together, calling back and forth, before landing again farther along the beach. The distance from roosts to intertidal feeding areas may be as little as 1000 m (3300 ft), or several kilometers.

March - April


Willets two years of age and older end their winter foraging along the west coast from northern California to South America and migrate to their breeding grounds, the interior West from southern Alberta to eastern South Dakota, and southward to northeastern California and western Colorado. In the east, Willets leave Maryland and points south to breed along the Atlantic Coast from Newfoundland and Nova Scotia, Florida and Texas, to Mexico and the West Indies.

April - July


Willets breed in two distinct habitats. Western Willets Catoptrophorus semipalmatus inornata breed in freshwater prairie marshes in the Great Plains of western North America. The Eastern Willet Catoptrophorus semipalmatus semipalmatus prefers coastal salt marshes from Newfoundland and Nova Scotia south to Mexico. Both nest on the ground in well-hidden locations, sometimes in loose colonies. The female chooses the nest site. The male displays for her, strutting his white wing flash marks and bowing. Clutch size is generally 4 eggs. Both parents incubate the eggs for 22 to 29 days. The male incubates the eggs at night. The chicks are precocial and are feeding themselves within 24 hours of hatching. Western Willet chicks feed primarily on flies taken from the surface of water. Both parents attend them for two to three weeks, when the female departs. The male parent stays with his young until they are about 28 days old, when he too departs. In less than a week the chicks also depart their summer breeding and feeding grounds. If the first clutch is destroyed and second clutch will be attempted.

June - August


Parents of successful first clutches and their chicks can be ready to migrate to winter feeding grounds as early as June. Later breeders or second clutches may not be able to leave the breeding grounds until August. Western Willets head for the west coasts of Oregon, California, and on to South America. Eastern Willets winter from Maryland south to South America.

July - February


Wintering along both west and east coasts, the Willet feeds along beaches and mudflats and shallow water, eating crabs, mollusks, small fishes, aquatic insects, marine worms, crustaceans, and some plant material. Willets use their bill to pick up food items or to probe in mud or sand for buried prey. They will wade in shallow water and follow the tide as it recedes. They are fairly solitary feeders, straying from each other on the beach or mud, but all will startle and rise in unison to fly a short distance away from the disturbance, landing again a few meters away. They are often seen in mixed flocks of Whimbrels, Marbled Godwits, and Curlews. In the MBNMS area, Del Monte Beach in Monterey is a good place to find Willets as is Jetty Road near Elkhorn Slough.

Listing Status:

The Willet’s population declined due to hunting in the 19th and early 20th centuries. Now, their population has increased, but habitat loss puts them at risk. The IUCN lists the Willet as a species of Least Concern (IUCN 3.1).
Click on an image below to view a larger version in the SIMoN Photo Library. You will also be able to view important information on each photo such as photographer, date, caption and more.
Ehrlich, P., D.S. Dobkin, and D. Wheye. 1988. The Birders Handbook: A Field Guide to the Natural History of North American Birds. Simon & Schuster Inc., New York. 785 p.
Schoenherr, A. A. 1995. A Natural History of California. University of California Press. 772 p.
Sibley, D.A. 2000. The Sibley Guide to Bird. Alfred A. Knopf, Inc. 545 p.
Swarth, C. 1988. California Wildlife Habitat Relationships System, California Department of Fish and Game, California Interagency Wildlife Task Group: Willet. Note: Life history accounts for species in the California Wildlife Habitat Relationships (CWHR) System were originally published in: Zeiner, D.C., W.F.Laudenslayer, Jr., K.E. Mayer, and M. White, eds. 1988-1990. California's Wildlife. Vol. I-III. California Depart. of Fish and Game, Sacramento, California.
Birds of Nova Scotia. 1998.
Nova Scotia Museum of Natural History

WWW Field Guides. 2007

Great Plains Nature Center. 2009.

WWW Field Guide to Birds of North America.