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.

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 , 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.

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.

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