Cox's Sandpiper
Encyclopedia
Cox's Sandpiper is the name given to shorebirds which are hybrids between male Pectoral
and female Curlew Sandpiper
s. It was discovered in Australia
in the 1950s, and named after Australian ornithologist John B. Cox
. Originally described by other Australian ornithologists as a species new to science
, it was later found to be a hybrid between two other common sandpiper species. Most if not all birds found to date are males, in accord with Haldane's rule
.
s, but as more birds were discovered (particularly in the period between 1968 and 1975) doubts were cast on this identification. By 1986, at least 20 such birds had been observed in various locations on the south and east coasts of the continent, although no consensus existed about their identity; among the theories postulated were that the birds were aberrant individual or a previously undescribed subspecies
of the Dunlin
, or that they were a stereotyped hybrid (meaning that all birds of some hybrid parentage appear near-identical). In order to help resolve the problem of the birds' identity John Cox collected two specimens, one in 1975 and another in 1977, and deposited them at the South Australian Museum
. Thinking that the birds might be "Cooper's Sandpipers" (see below), the two specimens were sent to the American Museum of Natural History
in 1977 for comparison with the type specimen from which that form was named; replies indicated that the birds were not of the same species (Buckley 1988). A live bird was caught and photographed in 1981, and, in 1982, Shane Parker
formally described the bird as a new species
(Parker 1982).
Following Parker's description, the view that these birds represented a good species (as opposed to aberrant individuals or hybrids) gained some ground; the 'species' was listed in the Shorebirds volume of the Helm Identification Guides
(Prater et al. 1986) for example, although with a note indicating that the possibility of hybrid origin could not be ruled out.
s. The bill is fairly long, blackish and slightly drooping, sometimes with a yellowish base; the legs are dull brownish-green in colour. The birds' wings at rest extend just slightly beyond the tail.
Cox's Sandpiper has never been observed in breeding plumage
. It is possible none exists, as it would require the birds to have functioning gonads (an uncertain possibility). All mature specimens that have been observed have been in non-breeding plumage, although some have started to acquire a few breeding-plumage feathers. In non-breeding plumage, birds are brown-grey above and white below, with a brown-grey breast-band and no flank-streaks. When hints of a breeding plumage are acquired, a rusty tinge develops on the breast and ear-coverts, some flank streaks appear, and on the upper parts the non-breeding-plumaged feathers are replaced by feathers with black centres, grey tips and buff or pale chestnut fringes. In both plumages, the breast-band is not as distinctly demarcated from the rest of the underparts as on Pectoral Sandpiper, and no birds have been observed which display the characteristic flank-chevrons shown by Sharp-tailed Sandpiper. Also, more white is present on the uppertail-coverts of Cox's Sandpiper than on the parent species.
Juvenile Cox's Sandpipers are known from only two individuals, one from Massachusetts
(Grant, 1987; Kasprzyk et al., 1987; Vickery et al., 1987, and Buckley, 1988). and one from Japan
(Ujihara 2002), both believed to be Cox's Sandpiper based on their morphology, but not identified with certainty. These birds closely resembled juvenile Pectoral Sandpipers, but without a well-demarcated breast-band (although the Japanese bird showed strong streaking on the breast-sides). In this plumage, the birds also showed large amounts of white on the uppertail-coverts.
in 1858 based on a specimen collected on Long Island
, New York
, in May 1833 and deposited at the American Museum of Natural History
. It was named after the conchologist
William Cooper
, who collected the bird.
When John Cox examined slides of the specimen in February 1988, he found a number of features in common with the Australian birds. The birds appeared to be of the same size and structure, with several plumage features in common including a heavily streaked head and neck with a rusty wash, a split supercilium, and identically-patterned upperparts feathers. Although the bill of the Cooper's specimen was straight (compared to the drooping bill of Cox's), this could be due to damage and distortion. The birds do differ insofar as that the Cooper's specimen has a spotted, not streaked breast. This could be accounted for by the plumage stage, given the differences in the times of year when the specimens were collected; also, some of the Cox's Sandpipers seen in Australia have had similar underparts markings to the Cooper's specimen. Nonetheless, those that have directly compared the Cooper's and Cox's sandpipers feel that they are not identical (Buckley, 1988; Cox, 1990).
, Plymouth Bay
, Massachusetts, USA, in September, 1987, and was tentatively identified as a Cox's Sandpiper. The bird was observed in the field, and also trapped and examined in the hand as well as banded. Several accounts of this individual were published (Grant, 1987; Kasprzyk et al., 1987; Vickery et al., 1987, and Buckley, 1988).
In late August, 2001, another juvenile Calidris showing features of both Pectoral and Curlew Sandpipers was found at Shintone
, Ibaraki Prefecture
, Japan
. An account of this bird, illustrated with photographs, was published in the British journal Birding World
(Ujihara 2002). This bird was believed to be another juvenile "Cox's Sandpiper".
of the cytochrome b
gene
was identical to that of Curlew Sandpipers, while allozyme
variation fit the pattern seen in Curlew and Pectoral Sandpipers, but neither agreed with that of other proposed parent species (Sharp-tailed Sandpiper, White-rumped Sandpiper
, and Ruff). Since mtDNA is inherited only from the mother, they concluded that the parentage of Cox's Sandpipers was a male Pectoral and a female Curlew 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...
and female 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...
s. It was discovered in 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...
in the 1950s, and named after Australian ornithologist John B. Cox
John B. Cox
John B. Cox is a British-born ornithologist, who emigrated to Australia in 1968.The hybrid shorebird Cox's Sandpiper was named after him by Shane Parker.-References:...
. Originally described by other Australian ornithologists as a species new to science
Bird species new to science
This article describes bird species new to science since 1900. Prior to the 20th century, and indeed into its early decades, the pace of discovery of new species was fast; during this period, with numerous collecting expeditions into species-rich areas not previously visited by western...
, it was later found to be a hybrid between two other common sandpiper species. Most if not all birds found to date are males, in accord with Haldane's rule
Haldane's rule
Haldane's rule or Haldane's law was formulated in 1922 by the British evolutionary biologist J.B.S. Haldane. It describes hybrid sterility in species and is extended to describe speciation in evolutionary theory, in two parts: the rule of hybrid sterility and the rule of hybrid inviability...
.
Discovery and naming
The first Cox's Sandpiper was recorded in Australia in 1955. Observers initially felt that the birds were DunlinDunlin
The Dunlin, Calidris alpina, is a small wader, sometimes separated with the other "stints" in Erolia. It is a circumpolar breeder in Arctic or subarctic regions. Birds that breed in northern Europe and Asia are long-distance migrants, wintering south to Africa, southeast Asia and the Middle East...
s, but as more birds were discovered (particularly in the period between 1968 and 1975) doubts were cast on this identification. By 1986, at least 20 such birds had been observed in various locations on the south and east coasts of the continent, although no consensus existed about their identity; among the theories postulated were that the birds were aberrant individual or a previously undescribed subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the Dunlin
Dunlin
The Dunlin, Calidris alpina, is a small wader, sometimes separated with the other "stints" in Erolia. It is a circumpolar breeder in Arctic or subarctic regions. Birds that breed in northern Europe and Asia are long-distance migrants, wintering south to Africa, southeast Asia and the Middle East...
, or that they were a stereotyped hybrid (meaning that all birds of some hybrid parentage appear near-identical). In order to help resolve the problem of the birds' identity John Cox collected two specimens, one in 1975 and another in 1977, and deposited them at the South Australian Museum
South Australian Museum
The South Australian Museum is a museum in Adelaide, South Australia, founded in 1856. It occupies a complex of buildings on North Terrace in the cultural precinct of the Adelaide Parklands.-History:...
. Thinking that the birds might be "Cooper's Sandpipers" (see below), the two specimens were sent to the American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
in 1977 for comparison with the type specimen from which that form was named; replies indicated that the birds were not of the same species (Buckley 1988). A live bird was caught and photographed in 1981, and, in 1982, Shane Parker
Shane A. Parker
Shane A. Parker was a British-born museum curator and ornithologist, who emigrated to Australia in 1967 after participating in the second Harold Hall Australian ornithological collecting expedition in 1964...
formally described the bird as a new species
Bird species new to science
This article describes bird species new to science since 1900. Prior to the 20th century, and indeed into its early decades, the pace of discovery of new species was fast; during this period, with numerous collecting expeditions into species-rich areas not previously visited by western...
(Parker 1982).
Following Parker's description, the view that these birds represented a good species (as opposed to aberrant individuals or hybrids) gained some ground; the 'species' was listed in the Shorebirds volume of the Helm Identification Guides
Helm Identification Guides
The Helm Identification Guides are a series of books that identify groups of birds. The series include two types of guides, those that are:* Taxonomic, dealing with a particular family of birds on a worldwide scale—most early Helm Guides were this type, as well as many more-recent ones,...
(Prater et al. 1986) for example, although with a note indicating that the possibility of hybrid origin could not be ruled out.
Appearance
Cox's Sandpiper is similar in size and shape to Pectoral and Sharp-tailed SandpiperSharp-tailed Sandpiper
The Sharp-tailed Sandpiper, Calidris acuminata is a small wader.- Taxonomy :More recently, a review of new data has indicated that this bird should perhaps better be placed into the genus Philomachus- as P...
s. The bill is fairly long, blackish and slightly drooping, sometimes with a yellowish base; the legs are dull brownish-green in colour. The birds' wings at rest extend just slightly beyond the tail.
Cox's Sandpiper has never been observed in breeding 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...
. It is possible none exists, as it would require the birds to have functioning gonads (an uncertain possibility). All mature specimens that have been observed have been in non-breeding plumage, although some have started to acquire a few breeding-plumage feathers. In non-breeding plumage, birds are brown-grey above and white below, with a brown-grey breast-band and no flank-streaks. When hints of a breeding plumage are acquired, a rusty tinge develops on the breast and ear-coverts, some flank streaks appear, and on the upper parts the non-breeding-plumaged feathers are replaced by feathers with black centres, grey tips and buff or pale chestnut fringes. In both plumages, the breast-band is not as distinctly demarcated from the rest of the underparts as on Pectoral Sandpiper, and no birds have been observed which display the characteristic flank-chevrons shown by Sharp-tailed Sandpiper. Also, more white is present on the uppertail-coverts of Cox's Sandpiper than on the parent species.
Juvenile Cox's Sandpipers are known from only two individuals, one from Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
(Grant, 1987; Kasprzyk et al., 1987; Vickery et al., 1987, and Buckley, 1988). and one from Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
(Ujihara 2002), both believed to be Cox's Sandpiper based on their morphology, but not identified with certainty. These birds closely resembled juvenile Pectoral Sandpipers, but without a well-demarcated breast-band (although the Japanese bird showed strong streaking on the breast-sides). In this plumage, the birds also showed large amounts of white on the uppertail-coverts.
The original specimen of "Cooper's" Sandpiper
Cooper's Sandpiper, "Calidris" × cooperi was described (as Tringa cooperi) by Spencer Fullerton BairdSpencer Fullerton Baird
Spencer Fullerton Baird was an American ornithologist, ichthyologist and herpetologist. Starting in 1850 he was assistant-secretary and later secretary of the Smithsonian Institution in Washington, D.C...
in 1858 based on a specimen collected on Long Island
Long Island
Long Island is an island located in the southeast part of the U.S. state of New York, just east of Manhattan. Stretching northeast into the Atlantic Ocean, Long Island contains four counties, two of which are boroughs of New York City , and two of which are mainly suburban...
, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
, in May 1833 and deposited at the American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
. It was named after the conchologist
Conchology
Conchology is the scientific or amateur study of mollusc shells. Conchology is one aspect of malacology, the study of molluscs, however malacology studies molluscs as whole organisms, not just their shells. Conchology pre-dated malacology as a field of study. It includes the study of land and...
William Cooper
William Cooper (conchologist)
William Cooper was an American conchologist and collector.Cooper studied zoology in Europe from 1821 to 1824, and afterwards travelled to Nova Scotia, Kentucky and the Bahamas collecting specimens. Although he was not an author himself his specimens were of great help to others, such as John James...
, who collected the bird.
When John Cox examined slides of the specimen in February 1988, he found a number of features in common with the Australian birds. The birds appeared to be of the same size and structure, with several plumage features in common including a heavily streaked head and neck with a rusty wash, a split supercilium, and identically-patterned upperparts feathers. Although the bill of the Cooper's specimen was straight (compared to the drooping bill of Cox's), this could be due to damage and distortion. The birds do differ insofar as that the Cooper's specimen has a spotted, not streaked breast. This could be accounted for by the plumage stage, given the differences in the times of year when the specimens were collected; also, some of the Cox's Sandpipers seen in Australia have had similar underparts markings to the Cooper's specimen. Nonetheless, those that have directly compared the Cooper's and Cox's sandpipers feel that they are not identical (Buckley, 1988; Cox, 1990).
Pattern of records in Australia
Most records to date have come from the more heavily-populated south and south-east of Australia.Records outside Australia
A mysterious juvenile Calidris sandpiper was encountered on Duxbury BeachDuxbury Beach
Duxbury Beach is a beach in the town of Duxbury, Massachusetts. It is four miles long and is accessed by the Powder Point Bridge from Duxbury.It is a barrier beach, defined by sand dunes, rosa ragusa, and beach grass...
, Plymouth Bay
Plymouth Bay
Plymouth Bay is the name of a small, well-protected bay of the Atlantic Ocean on the western shore of larger Cape Cod Bay along the coastline of the Commonwealth of Massachusetts...
, Massachusetts, USA, in September, 1987, and was tentatively identified as a Cox's Sandpiper. The bird was observed in the field, and also trapped and examined in the hand as well as banded. Several accounts of this individual were published (Grant, 1987; Kasprzyk et al., 1987; Vickery et al., 1987, and Buckley, 1988).
In late August, 2001, another juvenile Calidris showing features of both Pectoral and Curlew Sandpipers was found at Shintone
Shintone, Ibaraki
Shintone was a town located in Inashiki District, Ibaraki, Japan.On March 22, 2005 Shintone was merged with the towns of Azuma and Edosaki, and the village of Sakuragawa, all from Inashiki District, to form the new city of Inashiki and no longer exists as an independent municipality.In 2003, the...
, Ibaraki Prefecture
Ibaraki Prefecture
is a prefecture of Japan, located in the Kantō region on the main island of Honshu. The capital is Mito.-History:Ibaraki Prefecture was previously known as Hitachi Province...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. An account of this bird, illustrated with photographs, was published in the British journal Birding World
Birding World
Birding World is a monthly birding magazine published in the United Kingdom. It is the magazine of the Bird Information Service, based at Cley next the Sea, Norfolk....
(Ujihara 2002). This bird was believed to be another juvenile "Cox's Sandpiper".
The mystery solved
The birds were conclusively shown to be hybrids by Christidis et al. (1996). They analyzed 3 specimens of Cox's Sandpiper and found that the mtDNA sequenceDNA 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...
of the cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
was identical to that of Curlew Sandpipers, while allozyme
Allozyme
Variant forms of an enzyme that are coded by different alleles at the same locus are called allozymes. These are opposed to isozymes, which are enzymes that perform the same function, but which are coded by genes located at different loci....
variation fit the pattern seen in Curlew and Pectoral Sandpipers, but neither agreed with that of other proposed parent species (Sharp-tailed Sandpiper, White-rumped Sandpiper
White-rumped Sandpiper
The White-rumped Sandpiper is a small shorebird.Adults have black legs and a small thin dark bill. The body is dark brown on top and mainly white underneath, with brown streaks on the breast and a white rump. They have a white stripe over their eyes. This bird shows long wings in flight. In winter...
, and Ruff). Since mtDNA is inherited only from the mother, they concluded that the parentage of Cox's Sandpipers was a male Pectoral and a female Curlew Sandpiper.
External links
- Juvenile Calidris Hybrid ? Photos of the 2001 Shintone specimen.