Sharp-tailed Sandpiper
The Sharp-tailed Sandpiper, Calidris acuminata (but see below) is a small wader
Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...



More recently, a review of new data has indicated that this bird should perhaps better be placed into the genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

- as P. acuminatus - which now contains only the ruff but if the Sharp-tailed Sandpiper is merged into it would need to accommodate the Broad-billed Sandpiper
Broad-billed Sandpiper
The Broad-billed Sandpiper is a small wading bird. It is the only member of the genus Limicola; some have proposed that it should be placed in the genus Erolia with the "stint" sandpipers, but more recent research suggests that it is should rather go into the genus Philomachus with the ruff and...

 also (Thomas et al., 2004).

While the latter certainly is a most peculiar calidrid
The calidrids or typical waders are a group of Arctic-breeding, strongly migratory wading birds. These birds form huge mixed flocks on coasts and estuaries in winter. They are the typical "sandpipers", small to medium-sized, long-winged and relatively short-billed.Their bills have sensitive tips...

, the Sharp-tailed Sandpiper is much more similar to other Calidris/Erolia species such as the Pectoral Sandpiper
Pectoral Sandpiper
The Pectoral Sandpiper, Calidris melanotos, is a small wader. It is sometimes separated with the "stint" sandpipers in Erolia. This may or may not represent a good monophyletic group, depending on the placement of the phylogenetically enigmatic Curlew Sandpiper , the type species of Erolia...

. On the one hand, its larger size and long-legged stance, and the breast pattern which gradually fades away on the belly as in the Ruff instead of having a fairly sharp border as in the Calidris/Erolia stint
A stint is one of several very small waders in the paraphyletic "Calidris" assemblage - often separated in Erolia -, which in North America are known as peeps...

s indicate that placement in Philomachus may be correct. Still, it is just as possible that - given the fairly common instances of hybridization in calidrines - mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...

 data has given a false picture of this species' true affinities. The Curlew Sandpiper
Curlew Sandpiper
The Curlew Sandpiper is a small wader that breeds on the tundra of Arctic Siberia. It is strongly migratory, wintering mainly in Africa, but also in south and southeast Asia and in Australasia...

, which is a proposed parent of the hybrid called "Cooper's Sandpiper" ("Calidris" × cooperi) together with the Sharp-tailed Sandpiper, is another unusual calidrid that is hard to place systematically.

Distribution and habitat

It breeds in the boggy tundra of northeast Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 and is strongly migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

, wintering in south east Asia and Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...

. It occurs as a rare autumn migrant to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, but in western Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 only as a very rare vagrant.


Breeding adults are a rich brown with darker feather centres above, and white underneath apart from a buff breast. They have a light superciliary line above the eye and a chestnut crown. In winter, Sharp-tailed Sandpipers are grey above. The juveniles are brightly patterned above with rufous colouration and white mantle stripes.

This bird looks a lot like the Pectoral Sandpiper, within whose Asian range it breeds. It differs from that species in its breast pattern, stronger supercilium
The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...

 and more rufous crown. It has some similarities to the Long-toed Stint
Long-toed Stint
The Long-toed Stint, Calidris or Erolia subminuta, is a small wader bird. It breeds across northern Asia and is strongly migratory, wintering in south and south east Asia and Australasia...

, but is much larger than that tiny stint
A stint is one of several very small waders in the paraphyletic "Calidris" assemblage - often separated in Erolia -, which in North America are known as peeps...



Little is known of the breeding habits of this species, although it nests on the ground, and the male has a display flight.


These birds forage on grasslands and mudflats, like the Pectoral Sandpiper, picking up food by sight, sometimes by probing. They mainly eat insects and other invertebrates.

External links

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