Waders, called Shorebirds
in North America (where "wader" is used to refer to
long-legged wading birds such as storks and herons), are members
of the order Charadriiformes, excluding the more marine web-footed
seabird groups. The latter are the skuas (Stercoraracidae), gulls
(Laridae), terns (Sternidae), skimmers (Rhynchopidae), sheathbill
(Chionididae) and auks (Alcidae). This leaves about 210 species,
most of which are associated with 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 Little
Stint are amongst the longest distance migrants, wintering in
the southern hemisphere The majority of species eat small invertebrates
picked out of the mud or soil. Different lengths of bills enable
different species to feed in the same habitat, particularly on
the coast, without direct competition for food.
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Many waders have
sensitive nerve endings at the end of their bills which enable
them to detect prey items hidden in mud or soft soil. Some larger
species, particularly those adapted to drier habitats will take
larger prey including insects and small reptiles. The pratincoles
are aerial insect eaters, hunting like swallows. 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.
Above Pictures From The U.S. Fish and Wildlife Service
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