This group gathers Birds subcategory members that do not belong to any of this subcategory's other, more narrowly defined order-based groups, spanning several distinct non-passerine orders too small on their own, within this subcategory's membership, to warrant a separate heading. It includes the gamebirds of the order Galliformes, the chickens, turkeys, pheasants, grouse, quail, peafowl and their relatives, most of which spend much of their lives on the ground; the cranes, rails, crakes, moorhens, coots, the kagu and the bustards, loosely allied ground and wetland birds historically grouped near Gruiformes; the swifts and their close relatives the hummingbirds, both capable of extraordinarily fast or sustained flight on rapidly beating wings; the nightjar and its relative the oilbird, nocturnal or crepuscular birds with wide gapes suited to catching insects or, in the oilbird's case, echolocating in dark caves; the flamingos, filter-feeding wading birds of shallow saline lakes; the resplendent quetzal, a trogon prized for its iridescent tail plumes; and the hoatzin, a leaf-eating South American bird whose chicks retain clawed wings, itself so evolutionarily distinct that its own place on the bird family tree remains debated.