Sandpiper

Scolopacidae is a large family of shorebirds, or waders, which mainly includes many species known as sandpipers, but also others such as woodcocks, curlews, and snipes. Most of these species eat small invertebrates picked out of the mud or soil. There is no evidence that different lengths of bills enable multiple species to feed in the same habitat, particularly on the coast, without direct competition for food. On sandy beaches, species with different bill lengths feed on the only abundant invertebrate, such as mole crabs Emerita.
Sandpipers have long bodies and legs, and narrow wings. Most species have a narrow bill, but the form and length are variable. They are small to medium-sized birds, measuring in length. The bills are sensitive, allowing the birds to feel the mud and sand as they probe for food. They generally have dull plumage, with cryptic brown, grey, or streaked patterns, although some display brighter colours during the breeding season.
Most species nest in open areas and defend their territories with aerial displays. The nest itself is a simple scrape in the ground, in which the bird typically lays three or four eggs. The young of most species are precocial.

Taxonomy

The family Scolopacidae was introduced by the French polymath Constantine Samuel Rafinesque in 1815. The family contains 98 extant or recently extinct species divided into 15 genera. For more details, see the article List of sandpiper species.
The following genus-level cladogram of the Scolopacidae is based on a study by David Černý and Rossy Natale that was published in 2022.

Image	Genus	Living and recently extinct species
	Bartramia	Upland sandpiper, Bartramia longicauda
	Numenius	Bristle-thighed curlew, Numenius tahitiensis Eurasian whimbrel, Numenius phaeopus Hudsonian whimbrel, Numenius hudsonicus Little curlew, Numenius minutus †? Eskimo curlew, Numenius borealis Long-billed curlew, Numenius americanus Far Eastern curlew, Numenius madagascariensis † Slender-billed curlew, Numenius tenuirostris Eurasian curlew, Numenius arquata
	Limosa	Bar-tailed godwit, Limosa lapponica Black-tailed godwit, Limosa limosa Hudsonian godwit, Limosa haemastica Marbled godwit, Limosa fedoa
	Limnodromus	Asian dowitcher, Limnodromus semipalmatus Long-billed dowitcher, Limnodromus scolopaceus Short-billed dowitcher, Limnodromus griseus
	Lymnocryptes	Jack snipe, Lymnocryptes minimus
	Scolopax	American woodcock, Scolopax minor Eurasian woodcock, Scolopax rusticola Amami woodcock, Scolopax mira Bukidnon woodcock, Scolopax bukidnonensis Javan woodcock, Scolopax saturata New Guinea woodcock, Scolopax rosenbergii Sulawesi woodcock, Scolopax celebensis Moluccan woodcock, Scolopax rochussenii
	Coenocorypha	† North Island snipe, Coenocorypha barrierensis Oliver, 1955 – also known as the Little Barrier Snipe † South Island snipe, Coenocorypha iredalei Rothschild, 1921 – also known as the Stewart Island Snipe Chatham snipe, Coenocorypha pusilla – Chatham Islands Snares snipe, Coenocorypha huegeli – Snares Islands Subantarctic snipe, Coenocorypha aucklandica * Auckland snipe, C. a. aucklandica – Auckland Islands * Antipodes snipe, C. a. meinertzhagenae Rothschild, 1927 – Antipodes Islands * Campbell snipe, C. a. perseverance Miskelly & Baker, 2010 – Campbell Island † Forbes's snipe, Coenocorypha chathamica – Chatham Islands † Viti Levu snipe, Coenocorypha miratropica Worthy, 2003 – Fiji † New Caledonian snipe, Coenocorypha neocaledonica Worthy et al., 2013 – New Caledonia † Norfolk snipe, Coenocorypha sp. – Norfolk Island
	Gallinago	Imperial snipe, Gallinago imperialis Jameson's snipe, Gallinago jamesoni Fuegian snipe, Gallinago stricklandii Solitary snipe, Gallinago solitaria Wood snipe, Gallinago nemoricola Great snipe, Gallinago media Swinhoe's snipe, Gallinago megala Pin-tailed snipe, Gallinago stenura Latham's snipe, Gallinago hardwickii African snipe, Gallinago nigripennis Common snipe, Gallinago gallinago Wilson's snipe, Gallinago delicata Giant snipe, Gallinago undulata Noble snipe, Gallinago nobilis Puna snipe, Gallinago andina Madagascar snipe, Gallinago macrodactyla Pantanal snipe, Gallinago paraguaiae Magellanic snipe, Gallinago magellanica
	Phalaropus	Wilson's phalarope, Phalaropus tricolor Red phalarope, Phalaropus fulicarius Red-necked phalarope, Phalaropus lobatus
	Xenus	Terek sandpiper, Xenus cinereus
	Actitis	Common sandpiper, Actitis hypoleucos Spotted sandpiper, Actitis macularius
	Tringa	Green sandpiper, Tringa ochropus Solitary sandpiper, Tringa solitaria Grey-tailed tattler, Tringa brevipes Wandering tattler, Tringa incana Marsh sandpiper, Tringa stagnatilis Wood sandpiper, Tringa glareola Common redshank, Tringa totanus Lesser yellowlegs, Tringa flavipes Nordmann's greenshank, Tringa guttifer Willet, Tringa semipalmata Spotted redshank, Tringa erythropus Common greenshank, Tringa nebularia Greater yellowlegs, Tringa melanoleuca
	Prosobonia	† Kiritimati sandpiper, Prosobonia cancellata † Tahiti sandpiper, Prosobonia leucoptera † Moorea sandpiper, Prosobonia ellisi Tuamotu sandpiper, Prosobonia parvirostris
	Arenaria	Ruddy turnstone, Arenaria interpres Black turnstone, Arenaria melanocephala
	Calidris	Great knot, Calidris tenuirostris Red knot, Calidris canutus Surfbird, Calidris virgata Ruff, Calidris pugnax Broad-billed sandpiper, Calidris falcinellus Sharp-tailed sandpiper, Calidris acuminata Stilt sandpiper, Calidris himantopus Curlew sandpiper, Calidris ferruginea Temminck's stint, Calidris temminckii Long-toed stint, Calidris subminuta Red-necked stint, Calidris ruficollis Spoon-billed sandpiper, Calidris pygmaea Buff-breasted sandpiper, Calidris subruficollis Sanderling, Calidris alba Dunlin, Calidris alpina Purple sandpiper, Calidris maritima Rock sandpiper, Calidris ptilocnemis Baird's sandpiper, Calidris bairdii Little stint, Calidris minuta Least sandpiper, Calidris minutilla White-rumped sandpiper, Calidris fuscicollis Pectoral sandpiper, Calidris melanotos Western sandpiper, Calidris mauri Semipalmated sandpiper, Calidris pusilla

Evolution

The early fossil record is scant for a group that was probably present at the non-avian dinosaurs' extinction. "Totanus" teruelensis is sometimes considered a scolopacid – maybe a shank – but may well be a larid; little is known of it.
Paractitis has been named from the Early Oligocene of Saskatchewan, while Mirolia is known from the Middle Miocene at Deiningen in the Nördlinger Ries. Most living genera would seem to have evolved throughout the Oligocene to Miocene with the waders perhaps a bit later; see the genus accounts for the fossil record.
In addition there are some indeterminable remains that might belong to extant genera or their extinct relatives:

Scolopacidae gen. et sp. indet.
Scolopacidae gen. et sp. indet.

Description

The sandpipers exhibit considerable range in size and appearance, the wide range of body forms reflecting a wide range of ecological niches. Sandpipers range in size from the least sandpiper, at as little as and in length, to the Far Eastern curlew, at up to in length, and the Eurasian curlew, at up to. Within species there is considerable variation in patterns of sexual dimorphism. Males are larger than females in ruffs and several sandpipers, but are smaller than females in the knots, curlews, phalaropes and godwits. The sexes are similarly sized in the snipes, woodcock and tringine sandpipers. Compared to the other large family of wading birds, the plovers, they tend to have smaller eyes, more slender heads, and longer thinner bills. Some are quite long-legged, and most species have three forward pointing toes with a smaller hind toe.
Sandpipers are more geared towards tactile foraging methods than the plovers, which favour more visual foraging methods, and this is reflected in the high density of tactile receptors in the tips of their bills. These receptors are housed in a slight horny swelling at the tip of the bill. Bill shape is highly variable within the family, reflecting differences in feeding ecology. Bill length relative to head length varies from three times the length of the head in the long-billed curlew to just under half the head length in the Tuamotu sandpiper. Bills may be straight, slightly upcurled or strongly downcurved. Like all birds, the bills of sandpipers are capable of cranial kinesis, literally being able to move the bones of the skull and specifically bending the upper jaw without opening the entire jaw, an act known as rhynchokinesis. It has been hypothesized this helps when probing by allowing the bill to be partly opened with less force and improving manipulation of prey items in the substrate. Rhynchokinesis is also used by sandpipers feeding on prey in water to catch and manipulate prey.

Distribution, habitat, and movements

The sandpipers have a cosmopolitan distribution, occurring across most of the world's land surfaces except for Antarctica and the driest deserts. A majority of the family breed at moderate to high latitudes in the Northern Hemisphere, in fact accounting for the most northerly breeding birds in the world. Only a few species breed in tropical regions, ten of which are snipes and woodcocks and the remaining species being the unusual Tuamotu sandpiper, which breeds in French Polynesia.

Diet and feeding

There are broadly four feeding styles employed by the sandpipers, although many species are flexible and may use more than one style. The first is pecking with occasional probing, usually done by species in drier habitats that do not have soft soils or mud. The second, and most frequent, method employed is probing soft soils, muds and sands for prey. The third, used by Tringa shanks, involves running in shallow water with the bill under the water chasing fish, a method that uses sight as well as tactile senses. The final method, employed by the phalaropes and some Calidris sandpipers, involves pecking at the water for small prey. A few species of scolopacids are omnivorous to some extent, taking seeds and shoots as well as invertebrates.

Breeding

Many sandpipers form monogamous pairs, but some sandpipers have female-only parental care, some male-only parental care, some sequential polyandry and other compete for the mate on the lek. Sandpipers lay three or four eggs into the nest, which is usually a vague depression or scrape in the open ground, scarcely lined with soft vegetation. In species where both parents incubate the eggs, females and males share their incubation duties in various ways both within and between species. In some pairs, parents exchange on the nest in the morning and in the evening so that their incubation rhythm follows a 24-hour day, in others each sex may sit on the nest continuously for up to 24 hours before it is exchanged by its partner. In species where only a single parent incubates the eggs, during the night the parent sits on the eggs nearly continuously and then during the warmest part of a day leaves the nest for short feeding bouts. Chicks hatch after about three weeks of incubation and are able to walk and forage within a few hours of hatching. A single parent or both parents guide and brood the chicks.