Wader

Waders
Temporal range:
Small bird with long legs standing at water's edge
Semipalmated sandpiper (Calidris pusilla)
Scientific classificationEdit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Clade: Gruimorphae
Order: Charadriiformes
Groups included
Cladistically included but traditionally excluded taxa
Flock of birds on a beach
Waders roosting on the beach at high tide
Flock of birds in flight above a rocky beach
Waders in flight
refer to caption
Common ringed plover wading on a shore
A flock of Dunlin and Red knot in Sweden

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 approximately 255 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 sanderling and grey plover, are amongst the longest distance migrants, spending the non-breeding season in the Southern Hemisphere; the bar-tailed godwit holds the global record for the longest non-stop flight of any bird, some flying over 13,000 km from Alaska to New Zealand.

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, and many others, like the wood sandpiper and solitary sandpiper, primarily use muddy or sandy margins of inland freshwater.

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 in length is to be the Far Eastern curlew, at about 63 cm (25 in) and 860 g (1 lb 14 oz), while the heaviest is the beach thick-knee at about 1 kg (2 lb 3 oz).