A handsome and striking large wader (shorebird) with a long wispy crest. Fairly common in open habitats, from grassland and farmland to wetlands, and locally on coastal mudflats. Declining in some areas with land-use changes. Forms flocks from late summer through winter, locally in hundreds or even thousands. Boldly patterned plumage looks black and white overall, but the back shows green gloss in good light. Flies with deep, rather floppy wingbeats and dives steeply in the breeding display; wingtips notably broad and rounded, not pointed like most waders.