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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. There are 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 as 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 and measure just over . The largest species is believed to be the Far Eastern curlew, at about and , although the beach thick-knee is the heaviest at about . In the Sibley-Ahlquist taxonomy, waders and many other groups are subsumed into a greatly enlarged Ciconiiformes order. However, the classification of the Charadriiformes is one of the weakest points of the Sibley-Ahlquist taxonomy, as DNA-DNA hybridization has turned out to be incapable of properly resolving the interrelationships of the group. Formerly, the waders were united in a single suborder Charadrii, but this has turned out to be a "wastebasket taxon", uniting no less than four charadriiform lineages in a paraphyletic assemblage. However, it indicated that the plains wanderer actually belonged into one of them. Following recent studies (Ericson ''et al.'', 2003; Paton ''et al.'', 2003; Thomas ''et al.'', 2004a, b; van Tuinen ''et al.'', 2004; Paton & Baker, 2006), the waders may be more accurately subdivided as follows: * Suborder Scolopaci * * Family Scolopacidae: snipe, sandpipers, phalaropes, and allies * Suborder Thinocori * * Family Rostratulidae: painted snipe * * Family Jacanidae: jacanas * * Family Thinocoridae: seedsnipe * * Family Pedionomidae: plains wanderer * Suborder Chionidi * * Family Burhinidae: thick-knees * * Family Chionididae: sheathbills * * Family Pluvianellidae: Magellanic plover * Suborder Charadrii * * Family Ibidorhynchidae: ibisbill * * Family Recurvirostridae: avocets and stilts * * Family Haematopodidae: oystercatchers * * Family Charadriidae: plovers and lapwings In keeping more in line with the traditional grouping, the Thinocori could be included in the Scolopaci, and the Chionidi in the Charadrii. However, the increasing knowledge about the early evolutionary history of modern birds suggests that the assumption of Paton ''et al.'' (2003) and Thomas ''et al.'' (2004b) of 4 distinct "wader" lineages (= suborders) already being present around the Cretaceous–Paleogene boundary is correct. == Characteristics == Shorebirds is a blanket term used to refer to multiple species of birds that live in wet, coastal environments. Because most these species spend much of their time near bodies of water, many have long legs suitable for wading (hence the name ‘Waders’). Some species prefer locations with rocks or mud. Many shorebirds display migratory patterns and often migrate before breeding season. These behaviors explain the long wing lengths observed in species, and can also account for the efficient metabolisms that give the birds energy during long migrations.〔"Explore the World With Shorebirds." U.S. Fish and Wildlife Service, 1 Aug. 2004. Web.< The majority of species eat small invertebrates picked out of mud or exposed soil. Different lengths of bills enable different species to feed in the same habitat, particularly on the coast, without direct competition for food. 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Wader」の詳細全文を読む スポンサード リンク
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