Calidrid

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Typical waders
Purple Sandpiper, a small sandpiper or "stint"
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Charadriiformes Family: Scolopacidae
Genera
see text

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 "peeps", small to medium-sized, long-winged and relatively short-billed.

Their bills have sensitive tips which enable them to locate buried prey items, which they typically seek with restless running and probing.

As the common name sandpiper is shared by some calidrids with more distantly related birds such as the Actitis species, the term stint is preferred in Britain for the smaller species of this group.

The calidrids' closest relatives are the two species of turnstone, and if the calidrids were to be considered a tribe Calidriini, the turnstones would be included in it.

The interrelationships of the calidrid group are not altogether well resolved. Several former genera have been included in Calidris, such as the Stilt Sandpiper (previously Micropalama himantopus)^{[citation needed]}, but the new placement was also not entirely satisfactory. It was suggested, for example, that the sanderling should be placed into a monotypic genus Crocethia^{[citation needed]}, and the other small Calidris species separated as Erolia^{[citation needed]}. Alternatively, it was suggested that the monotypic Aphriza, Limicola and Eurynorhynchus be also merged into Calidris.

A comprehensive analysis combining newly available data (Thomas et al, 2004) indicates that the extended Calidris is indeed paraphyletic (or polyphyletic if all calidrids are combined in it), but found the present DNA sequence data insufficient to resolve the relationships of some more unusual taxa such as the Curlew Sandpiper.

Still, three groups of close relatives emerge:

1. The largest contains the smaller species, including the Sanderling, and probably also the Buff-breasted Sandpiper. If it is considered a distinct genus, the name Erolia would only apply if the Curlew Sandpiper also belongs here, as this was the type species of Erolia when first published in 1816.
2. The genus Calidris sensu stricto contains the knots and the surfbird.
3. Another small group contains somewhat aberrant species, namely the Ruff, the Broad-billed Sandpiper, and the Sharp-tailed Sandpiper, which would use the name Philomachus.

The species, according to updated / traditional taxonomy, are as follows:

• Genus Calidris sensu stricto - knots
  • Surfbird, Calidris virgatus / Aphriza virgata
  • Great Knot, Calidris tenuirostris
  • Red Knot, Calidris canutus

Other calidrids (all at some time placed in Calidris too)

• Stints - possibly genus Erolia
  • Semipalmated Sandpiper, "Calidris" pusilla
  • Little Stint, "Calidris" minuta
  • Least Sandpiper, "Calidris" minutilla
  • White-rumped Sandpiper, "Calidris" fuscicollis
  • Baird's Sandpiper, "Calidris" bairdii
  • Dunlin, "Calidris" alpina
  • Red-necked Stint, "Calidris" ruficollis
  • Long-toed Stint, "Calidris" subminuta
  • Pectoral Sandpiper, "Calidris" melanotos
  • Sanderling, "Calidris" alba ("Crocethia alba")
  • Western Sandpiper, "Calidris" mauri
  • Purple Sandpiper, "Calidris" maritima
  • Rock Sandpiper, "Calidris" ptilocnemis
  • Temminck's Stint, "Calidris" temminckii
  • Buff-breasted Sandpiper, "Tryngites" subruficollis
• Genus Philomachus
  • Ruff, Philomachus pugnax
  • Broad-billed Sandpiper, Philomachus falcinellus / Limicola falcinellus ("Erolia falcinella")
  • Sharp-tailed Sandpiper, Philomachus acuminatus / Calidris acuminata
• Genus Micropalama (doubtfully valid; Erolius sensu stricto?)
  • Stilt Sandpiper, Micropalama himantopus / Calidris himantopus
• Genus Eurynorhynchus (doubtfully valid)
  • Spoon-billed Sandpiper, Eurynorhynchus pygmeus
• incertae sedis (Erolia sensu stricto?)
  • Curlew Sandpiper, ?Calidris ferruginea

[edit] See also

• Cox's Sandpiper
• Hybridisation in shorebirds

[edit] References

• Thomas, Gavin H.; Wills, Matthew A. & Székely, Tamás (2004): A supertree approach to shorebird phylogeny. BMC Evol. Biol. 4: 28. DOI:10.1186/1471-2148-4-28 PDF fulltext Supplementary Material