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 that do not fit the characters of known species. Many of these have been suspected of being hybrids. In several cases, shorebird hybrids have been described as new species before their hybrid origin was discovered. Compared to other groups of birds (such as gulls), only a few species of shorebirds are known or suspected to hybridize, but nonetheless, these hybrids occur quite frequently in some cases.
Hybrids in the Scolopaci (typical waders).
"Cooper's" and "Cox's" sandpipers.
An apparently new sandpiper species ("Cooper's sandpiper "Tringa"/"Calidris cooperi") was described in 1858 based on a specimen collected in 1833 on Long Island, New York. A similar bird was collected in 1981 at Stockton, New South Wales, Australia. These are probably hybrids between the curlew sandpiper ("Calidris" ferruginea") and the sharp-tailed sandpiper ("Philomachus acuminatus"/"Calidris acuminata").
Cox's sandpiper ("Calidris" × "paramelanotos"), described as a new species in 1982, is now known to be a stereotyped hybrid between males of the pectoral sandpiper (""Calidris" melanotos") and female curlew sandpipers. It is known from nearly two dozen sightings since the 1950s, almost all of which are from Australia, with one record from Massachusetts. and another from Japan.
Other hybrid scolopacids.
A stint at Groote Keeten in the Netherlands which was initially thought to be that country's first record of the least sandpiper but which showed anomalous features, was postulated to be a hybrid between little stint (""Calidris" minuta") and Temminck's stint (""Calidris" temminckii").
Putative hybrids between the dunlin (""Calidris" alpina") and the white-rumped sandpiper (""Calidris" fuscicollis") have been occasionally seen in northeastern North America. In Europe, on the other hand, an apparent hybrid between the dunlin and the purple sandpiper (""Calidris" maritima") has turned up.
Courtship and copulation have also been observed between common ("Actitis hypoleucos") and spotted sandpipers ("Actitis macularia"), but there are no records of hybrid offspring.
Occurrence of intrageneric hybridization has been reported between the buff-breasted sandpiper (""Tryngites" subruficollis") and the white-rumped (or possibly Baird's, ""Calidris" bairdii") sandpiper – the parent species apparently do belong into the same genus, however (see calidrid) -, as well as between the common and the green sandpiper ("Tringa ochropus").
Hybridisation in the Charadrii (oystercatchers, stilts, avocets and plovers).
Hybridisation between American ("Haematopus palliatus frazari") and black oystercatchers ("Haematopus bachmani") is relatively common in southern California and adjacent Mexico.
The "avistilt" or "stavocet" is a hybrid between black-necked stilt ("Himantopus mexicanus") and American avocet ("Recurvirostra americana"), occasionally found in California. One such bird was accidentally bred in the San Francisco Zoo in 1971 and lived at least until 1974. The avocet was the father and the stilt the mother of this individual, which apparently was a male.
The nearly extinct New Zealand black stilt ("Himantopus novaezelandiae") hybridizes with the pied stilt ("Himantopus leucocephalus"), which jeopardizes the survival of the former species.
A "Pluvialis" plover wintering with a flock of golden plover near Marksbury, England in 1987 was believed to be possibly a hybrid between golden plover and Pacific golden plover.