Charadriiformes is a diverse order of small to medium-large bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s. It includes about 350 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 and has members in all parts of the world. Most Charadriiformes live near water and eat invertebrate

Invertebrate

An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s or other small animals; however, some are pelagic (sea birds), some occupy deserts and a few are found in thick forest.
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The order was formerly divided into three suborders:

• The wader
  Wader
  Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...
  
  s (or "Charadrii"): typical shorebirds, most of which feed by probing in the mud or picking items off the surface in both coastal and freshwater environments.
• The gull
  Gull
  Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...
  
  s and their allies (or "Lari"): these are generally larger species which take fish from the sea.