Terek Sandpiper
Encyclopedia
The Terek Sandpiper is a small migratory
Palearctic
wader
species
, the only member of the genus
Xenus.
_w_img_6894.jpg)
Slightly larger than the Common Sandpiper
at 22–25 cm length, its long upcurved bill – somewhat reminiscent of an avocet
's, but not as strongly curved – makes it very distinctive. As the scientific specific name implies, this wader has a grey back, face and breast in all plumage
s; a white supercilium
may appear more or less distinct. The belly is whitish and the feet yellow; the bill
has a yellowish base, with the rest being black.
The call is a high whistle.
Among the Scolopacidae
, Xenus is part of the shank
-tattler
-phalarope
clade
and less closely related to the calidrid
sandpipers. Based on the degree of DNA sequence
divergence and putative shank and phalarope fossil
s from around the Oligocene
/Miocene
boundary some 23-22 million years ago, the Terek Sandpiper presumably diverged from their relatives in the Late Oligocene. Given the numerous basal fossils of the group found in Eurasia
it is likely that the Terek Sandpiper lineage originated there, possibly by being isolated as the remains of the Turgai Sea
dried up, which happened just around this time.
from Finland
through northern Siberia
to the Kolyma River
, and migrate
south in winter to tropical coasts in east Africa, south Asia and Australia
, usually preferring muddy areas. It is a rare vagrant in western Europe, and particularly in autumn it is sometimes seen passing through the Marianas on migration; on Palau
, further off its usual migration route, it is decidedly uncommon on the other hand. Almost annually and apparently more and more often in recent times, a few birds stray to Alaska
and the Aleutian and Pribilof Islands
. Every few years, individual vagrants are recorded in the Neotropics, where they arrive either as migrating birds from Africa, or as North American strays accompanying local waders south for winter. Such vagrants have been recorded as far south as Argentina
.
It feeds in a distinctive and very active way, chasing insects and other mobile prey, and sometimes then running to the water's edge to wash its catch. It lays three or four eggs in a lined ground scrape.
_w3_img_6891.jpg)
The Terek Sandpiper likes to associate with Ruddy Turnstone
s (Arenaria interpres), smallish calidrid
s, and Charadrius
(but maybe not Pluvialis
) plover
s; a vagrant bird at Paraty
(Rio de Janeiro state) was noted to pair up with a Spotted Sandpiper
(Actitis macularius). Thus it may be that the Terek Sandpiper under natural conditions may mate with Common Sandpiper
(A. hypoleucos) , the Old World sister species of Spotted Sandpiper
(A. macularius). As hybridisation in shorebirds
is extremely commonplace and Actitis is among the closer relatives of the Terek Sandpiper, such pairings (should they indeed occur) may produce hybrid offspring.
This is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA
) applies. Widespread and often quite commonly seen, the Terek Sandpiper is not considered a threatened species by the IUCN.
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...
Palearctic
Palearctic
The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...
wader
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...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, the only member of the genus
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...
Xenus.
Description and systematics
Common Sandpiper
The Common Sandpiper is a small Palearctic wader. This bird and its American sister species, the Spotted Sandpiper , make up the genus Actitis. They are parapatric and replace each other geographically; stray birds of either species may settle down with breeders of the other and hybridize...
at 22–25 cm length, its long upcurved bill – somewhat reminiscent of an avocet
Avocet
The four species of Avocets are a genus, Recurvirostra, of waders in the same avian family as the stilts.Avocets have long legs and long, thin, upcurved bills which they sweep from side to side when feeding in the brackish or saline wetlands they prefer...
's, but not as strongly curved – makes it very distinctive. As the scientific specific name implies, this wader has a grey back, face and breast in all plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
s; a white supercilium
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...
may appear more or less distinct. The belly is whitish and the feet yellow; the bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
has a yellowish base, with the rest being black.
The call is a high whistle.
Among the Scolopacidae
Scolopacidae
The sandpipers are a large family, Scolopacidae, of waders or shorebirds. They include many species called sandpipers, as well as those called by names such as curlew and snipe. The majority of these species eat small invertebrates picked out of the mud or soil...
, Xenus is part of the shank
Tringa
Tringa is a genus of waders, containing the shanks and tattlers. They are mainly freshwater birds, often with brightly coloured legs as reflected in the English names of six species, as well as the specific names of two of these and the Green Sandpiper. They are typically associated with northern...
-tattler
Tattler (bird)
The tattlers are the two very similar bird species in the shorebird genus Tringa. They formerly had their own genus, Heteroscelus. The old genus name means "different leg" in Greek, referring to the leg scales that differentiate the tattlers from their close relatives, the shanks.The species are:*...
-phalarope
Phalarope
A phalarope or wadepiper is any of three living species of slender-necked shorebirds in the genus Phalaropus of the bird family Scolopacidae. They are close relatives of the shanks and tattlers, the Actitis and Terek Sandpipers, and also of the turnstones and calidrids...
clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
and less closely related to the calidrid
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...
sandpipers. Based on the degree of DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
divergence and putative shank and phalarope fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s from around the Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
/Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
boundary some 23-22 million years ago, the Terek Sandpiper presumably diverged from their relatives in the Late Oligocene. Given the numerous basal fossils of the group found in Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
it is likely that the Terek Sandpiper lineage originated there, possibly by being isolated as the remains of the Turgai Sea
Turgai Sea
The Turgai Sea or Turgai Strait, also known as the West Siberian Sea, was a large shallow body of salt water of the Mesozoic and Cenozoic Eras...
dried up, which happened just around this time.
Distribution and ecology
This bird breeds near water in the taigaTaiga
Taiga , also known as the boreal forest, is a biome characterized by coniferous forests.Taiga is the world's largest terrestrial biome. In North America it covers most of inland Canada and Alaska as well as parts of the extreme northern continental United States and is known as the Northwoods...
from Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
through northern Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
to the Kolyma River
Kolyma River
The Kolyma River is a river in northeastern Siberia, whose basin covers parts of the Sakha Republic, Chukotka Autonomous Okrug, and Magadan Oblast of Russia. Itrises in the mountains north of Okhotsk and Magadan, in the area of and...
, and migrate
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...
south in winter to tropical coasts in east Africa, south Asia and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, usually preferring muddy areas. It is a rare vagrant in western Europe, and particularly in autumn it is sometimes seen passing through the Marianas on migration; on Palau
Palau
Palau , officially the Republic of Palau , is an island nation in the Pacific Ocean, east of the Philippines and south of Tokyo. In 1978, after three decades as being part of the United Nations trusteeship, Palau chose independence instead of becoming part of the Federated States of Micronesia, a...
, further off its usual migration route, it is decidedly uncommon on the other hand. Almost annually and apparently more and more often in recent times, a few birds stray to Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
and the Aleutian and Pribilof Islands
Pribilof Islands
The Pribilof Islands are a group of four volcanic islands off the coast of mainland Alaska, in the Bering Sea, about north of Unalaska and 200 miles southwest of Cape Newenham. The Siberia coast is roughly northwest...
. Every few years, individual vagrants are recorded in the Neotropics, where they arrive either as migrating birds from Africa, or as North American strays accompanying local waders south for winter. Such vagrants have been recorded as far south as Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
.
It feeds in a distinctive and very active way, chasing insects and other mobile prey, and sometimes then running to the water's edge to wash its catch. It lays three or four eggs in a lined ground scrape.
Ruddy Turnstone
The Ruddy Turnstone is a small wading bird, one of two species of turnstone in the genus Arenaria. It is now classified in the sandpiper family Scolopacidae but was formerly sometimes placed in the plover family Charadriidae...
s (Arenaria interpres), smallish calidrid
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...
s, and Charadrius
Charadrius
Charadrius is a genus of plovers, a group of wading birds. They are found throughout the world.Many of the Charadrius species are characterised by breast bands or collars...
(but maybe not Pluvialis
Pluvialis
Pluvialis is a genus of plovers, a group of wading birds. There are four species which breed in the temperate or Arctic Northern Hemisphere.In breeding plumage, they all have largely black underparts, and golden or silvery upperparts...
) plover
Plover
Plovers are a widely distributed group of wading birds belonging to the subfamily Charadriinae. There are about 40 species in the subfamily, most of them called "plover" or "dotterel". The closely related lapwing subfamily, Vanellinae, comprises another 20-odd species.Plovers are found throughout...
s; a vagrant bird at Paraty
Paraty
Paraty [pronounced Par-a-CHEE] is a preserved Portuguese colonial and Brazilian Imperial town with a population of about 36,000. It is located on the Costa Verde , a lush, green corridor that runs along the coastline of the state of Rio de Janeiro, in Brazil...
(Rio de Janeiro state) was noted to pair up with a Spotted Sandpiper
Spotted Sandpiper
The Spotted Sandpiper is a small shorebird, 18–20 cm long. Together with its sister species, the Common Sandpiper they make up the genus Actitis...
(Actitis macularius). Thus it may be that the Terek Sandpiper under natural conditions may mate with Common Sandpiper
Common Sandpiper
The Common Sandpiper is a small Palearctic wader. This bird and its American sister species, the Spotted Sandpiper , make up the genus Actitis. They are parapatric and replace each other geographically; stray birds of either species may settle down with breeders of the other and hybridize...
(A. hypoleucos) , the Old World sister species of Spotted Sandpiper
Spotted Sandpiper
The Spotted Sandpiper is a small shorebird, 18–20 cm long. Together with its sister species, the Common Sandpiper they make up the genus Actitis...
(A. macularius). As hybridisation in shorebirds
Hybridisation in shorebirds
Hybridisation in shorebirds has been proven on only a small number of occasions; however, many individual shorebirds have been recorded by birdwatchers worldwide which do not fit the characters of known species. Many of these have been suspected of being hybrids. In several cases, shorebird hybrids...
is extremely commonplace and Actitis is among the closer relatives of the Terek Sandpiper, such pairings (should they indeed occur) may produce hybrid offspring.
This is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA
AEWA
The Agreement on the Conservation of African-Eurasian Migratory Waterbirds is the largest of its kind developed so far under the Bonn Convention. It was concluded on 16 June 1995 at The Hague, the Netherlands and entered into force on 1 November 1999 after the required number of at least fourteen...
) applies. Widespread and often quite commonly seen, the Terek Sandpiper is not considered a threatened species by the IUCN.