66 To make identification easier, birds are divided into different groups, based on characteristics that they share. The biggest group of birds is the passerines (sparrow-shaped birds), which include the perching and singing birds. BIRD GROUPS Flightless birds This group contains species that run, but cannot fly. On land, they include ostriches, rheas, cassowaries, and kiwis. Wading birds Many birds, such as spoonbills, flamingos, and herons, wade into water to find food. Most have long legs and probing beaks to catch fish and crustaceans. Waterfowl Swans, geese, and ducks are waterfowl and live near rivers, ponds, and lakes. They have webbed feet and large beaks. Long, flexible neck Spoon-shaped bill sweeps sideways through water Mute swan Stocky build and upright stance Roseate spoonbill Strong legs for fast running Ostrich Long, shaggy wing feathers Stilt-like legs Juvenile greater flamingo Dagger- shaped bill Black-crowned night heron Rhea Short, thick toes Common shelduck Some ducks may have bold markings. Snowy owl Swan goose