Order containing around 370 species in 17 families including plovers, jacanas, stilts, avocets, thickknees, terns, and murres, having three basic body plans: waders (shorebirds) that usually feed on small animals in mud or water; web-footed dense-plumaged water birds that feed by plunging into water for fish, robbing other birds, or scavenging; and dense-plumaged, web-footed, marine, wing-propelled divers that feed on fish or invertebrates.