True climbers: parrots walk with beak, neck, and feet
Parrots, some 410 species found mostly in the tropics, rank with crows and ravens among the brainiest birds. They are also the only animals that truly climb on three limbs, hauling themselves up vertical surfaces with the beak and neck as hard as a primate pulls with its arms.
Four families make up the order: the Old World parrots, the African and New World parrots, the cockatoos, and the New Zealand parrots, whose members include the kea and the flightless, critically endangered kākāpō. Cockatoos stand apart with movable head crests, a gall bladder and differences in their arteries and skulls. Parrots vary more in length than any other bird order, and most males and females look alike to human eyes.
Diets rely on seeds, nuts, fruit and buds, although a few species eat animals or carrion and the lories and lorikeets are built for nectar and soft fruit. Nearly all nest in tree hollows and lay white eggs that hatch into helpless chicks. Genetic studies show their nearest relatives are the songbirds and other perching birds, from which they parted about 62 million years ago.
Their history is patchy. Molecular clocks put their origin around 59 million years ago in the southern supercontinent Gondwana, but fossils are rare there. A 15-millimetre bill fragment from Wyoming, about 70 million years old, was once hailed as the oldest parrot but may belong to a beaked dinosaur. The first undisputed fossils come from tropical Europe around 50 million years ago, and bones of fully modern parrots appear about 23 to 20 million years ago, with none known in the Southern Hemisphere before about 20 million years ago. The Greek name reached Europe through Ctesias in the fifth century BCE, borrowed from an Indian word for a bird, and English speakers once said popinjay.
Their appeal is also their danger. Trapping for pets, hunting, habitat loss and invasive competitors have hit parrots harder than any other wild bird group, and a third of species face extinction. By 2021 roughly 50 million parrots, half of all that exist, lived in captivity, mostly as household pets.
Source: Parrot
