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 |
| |
| Numenius | ||
| Limosa | ||
| Limnodromus | ||
| Lymnocryptes | ||
| Scolopax | ||
| Coenocorypha | ||
| Gallinago | ||
| Phalaropus | ||
| Xenus | ||
| Actitis | ||
| Tringa | ||
| Prosobonia | ||
| Arenaria | ||
| Calidris |
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
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.