Wader

Waders Temporal range: Late Oligocene–recent PreꞒ Ꞓ O S D C P T J K Pg N
Semipalmated sandpiper (Calidris pusilla)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Clade:	Neoaves
Order:	Charadriiformes
Groups included
(Eu)Charadrii Scolopaci Dromadidae Turnicidae (occasionally included) Glareolidae (occasionally included)
Cladistically included but traditionally excluded taxa
Laridae Stercorariidae Alcidae

Waders roosting on the beach at high tide

Waders in flight

Common ringed plover wading on a shore

Common greenshank and Common redshank.

Waders or shorebirds are birds of the order Charadriiformes commonly found wading along shorelines and mudflats in order to forage for food crawling or burrowing in the mud and sand, usually small arthropods such as aquatic insects or crustaceans. The term "wader" is used in Europe, while "shorebird" is used in North America, where "wader" may be used instead to refer to long-legged wading birds such as storks and herons.

There are about 210^[1] species of wader, most of which live in wetland or coastal environments. Many species of Arctic and temperate regions are strongly migratory, but tropical birds are often resident, or move only in response to rainfall patterns. Some of the Arctic species, such as the little stint, are amongst the longest distance migrants, spending the non-breeding season in the southern hemisphere.

Many of the smaller species found in coastal habitats, particularly but not exclusively the calidrids, are often named as "sandpipers", but this term does not have a strict meaning, since the upland sandpiper is a grassland species.

The smallest member of this group is the least sandpiper, small adults of which can weigh as little as 15.5 grams (0.55 oz) and measure just over 13 centimetres (5 inches). The largest species is believed to be the Far Eastern curlew, at about 63 cm (25 in) and 860 grams (1 pound 14 ounces), although the beach thick-knee is the heaviest at about 1 kg (2 lb 3 oz).