Parrots are a group of 328 species of birds native to many regions of the world. Members of Order Psittaciformes are generally thought of as parrots, although only members of the family Psittacidae are true parrots. The other two families in Psittaciformes are Cacatuidae (cockatoos) and Loriidae (lories and lorikeets). Cockatoos can be distinguished by a crest of feathers on the top of their heads and powdery down feathers. Lories and lorikeets differ from parrots primarily in their specialized diet, which consists almost entirely of pollen and nectar that they gather using a brush-like tongue. Parrots have a generally upright posture and large curved beaks which they use to crack nuts and seeds. They also have clawed zygodactyl feet, which means that they have two toes on each side of their foot to effectively grasp tree branches. Most parrots spend the majority of their time in the forest canopy and eat nuts, fruits, leaves, bark, flowers, buds, and seeds.