Sandpipers vary a great deal in size, from 4.7 to 26 inches (12 to 66 centimeters) in length and from 0.5 to 48 ounces (14.5 to 1,360 grams) in weight. Bill size and shape also vary a lot in the group, depending largely on the type of food eaten. Different sandpiper species have long or short bills, straight bills, upwardly curved bills, or downwardly curved bills. There are also more unusual bills, such as wedge-shaped bills and spoon-shaped bills, in the family. Some sandpipers have slender bodies, while others have plump bodies. Most species have short tails, long necks, long legs, and partially webbed toes. The wings tend to be long. Many sandpipers are colored to blend into their environments, although some species develop brighter black or reddish-colored patches during the breeding season. In many sandpipers, females and males are fairly similar in appearance. However, there are exceptions. In the ruff, for example, the male is 25 percent larger than the female and also has special feathers around the head and neck during the breeding season. Young sandpipers are generally colored to blend into their habitats.
Sandpipers are found worldwide on all continents except Antarctica. A large number of sandpipers breed in the Northern Hemisphere and migrate to the tropics or to the Southern Hemisphere for the winter. Only a small number of sandpipers breed in the tropics. The sandpiper family includes species which breed the farthest north of any birds, including on Franz Joseph Land, the Zemlya Islands, and the northern tip of Greenland.
Most sandpipers breed in inland freshwater wetlands, although a few species prefer to breed in coastal saltwater marshes. Snipes are found in marshes, swamps, and wet grassland habitats. Curlews make use of woodland, tundra, grassland, farmlands, and lakeshores. Some sandpiper species breed on gravelly or rocky tundra, treeless plains found in artic regions. Woodcocks inhabit deciduous forests, forests where there are four seasons and trees lose their leaves in the fall. Favored wintering areas for sandpipers include tropical wetlands such as river mouths, lakeshores, and marshes. The phalaropes are unusual in that they are pelagic (puhLAJ-ik), meaning they live on the open ocean, during the winter.
Sandpipers eat primarily invertebrates, animals without backbones, such as worms, mollusks, crustaceans, insects, and spiders. They also eat some vertebrates, animals with backbones, including small fish and amphibians. Some species will also eat plant material at certain times of year, often when insect prey is unavailable. Plant material eaten may include berries, rice, seeds, and green shoots.
Sandpiper species with short bills generally obtain food by pecking at it. Snipes and woodcocks probe mud with their bills to look for food. Shanks run after fish in shallow water with their bills submerged. They sometimes work together to drive entire schools of small fish into shallow areas. Phalaropes and a few other species peck tiny prey from the water, focusing on invertebrates such as shrimp and copepods. A few members of the family have unique feeding strategies. For example, turnstones flip over stones and shells to look for prey, and the Terek sandpiper runs after small burrowing crabs.
BEHAVIOR AND REPRODUCTION
During the nonbreeding season, many sandpiper species feed and rest in large flocks. Sandpipers also migrate in large flocks of just one species. Some sandpipers migrate distances as great as several thousand miles, having built up large fat deposits to sustain them during the trip.
During the breeding season, most sandpipers are territorial, and defend areas of land from other pairs. A few species, however, including the Asian dowitcher, common redshank, and some godwits and curlews, nest close together in breeding colonies. Most sandpiper species are monogamous (muh-NAH-guh-mus), with a single male mating with a single female, during the breeding season. However, polygyny (puh-LIH-juh-nee), a single male mating with multiple females, describes the mating behavior of the Eurasian woodcock, white-rumped sandpiper, sharp-tailed sandpiper, and several other species. Polyandry (PAH-lee-an-dree), a single female mating with multiple males, is found in the spotted sandpiper and also in some phalaropes. In the phalaropes, females defend territories while males take care of the nests and chicks alone.
Courtship in sandpipers most frequently involves singing in flight and displays related to finding a site to build the pair’s nest. Some species, including the ruff, buff-breasted sandpiper, and great snipe, have leks, special areas where males gather to display for females. Females go to the lek to choose a partner and mate. Species with leks are polygynous (puh-LIH-juh-nus), and males do not participate in care of eggs or young. The sandpiper nest is most commonly a shallow indentation scraped in the ground and lined with vegetation. However, some species build more complicated nests or use old tree nests that have been abandoned by other birds. Females usually lay four eggs at a time, although some species lay only two or three.
Eggs are colored to blend into the environment, and are typically pale with brown or black markings. Chicks hatch after about three weeks. Sandpiper chicks are precocial (preeKOH-shul), meaning they hatch able to move and covered with down. Chicks usually leave the nest within a day of hatching. Woodcocks and snipes feed their young, but other species do not. However, sandpiper parents do protect their chicks from potential predators by pretending to be injured or by trying to look like rodents, fluffing up their feathers, running, and making squeaky noises. Nonetheless, in most species of sandpipers, fewer than half the chicks survive their first year.
SANDPIPERS AND PEOPLE
Many species in the family, particularly the snipe and woodcock, are widely hunted for food or sport. Some sandpipers are considered pests because they eat crops, particularly rice, whereas others actually help farmers by eating large numbers of insects. Some sandpipers have also played significant roles in human folklore. One group of Australian Aborigines performs a “sandpiper dance” since the arrival of the birds marks the beginning of the rainy season. In the Russian Far East, inhabitants of the Chukchi Peninsula imitate the impressive dance of lekking male ruffs.
Two species of sandpipers are known to have gone extinct since 1600 C.E. These are the white-winged sandpiper of Tahiti and Ellis’s sandpiper of Moorea. Both were probably driven to extinction by rats brought to their island habitats by humans. Of the eighty-six sandpiper species currently in existence, two are Critically Endangered, facing an extremely high risk of extinction, including the Eskimo curlew, which has not been seen since the 1980s, and the slender-billed curlew. Both species were hunted in large numbers by humans and also suffer from habitat loss. The Nordmann’s greenshank is Endangered, facing a very high risk of extinction in the wild, due to hunting and habitat loss. The tuamotu sandpiper is Endangered because of habitat loss and human-introduced predators. The Vulnerable, facing a high risk of extinction, species in the family include the spoon-billed sandpiper, bristle-thighed curlew, wood snipe, Chatham snipe, Amami woodcock, and Moluccan woodcock. These species are affected by factors such as hunting, habitat destruction and disturbance, and predators introduced by humans.