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Parrots, also known as psittacines /ˈsɪtəsaɪnz/, are birds of the roughly 372 species in 86 genera that make up the order Psittaciformes, found in most tropical and subtropicalregions. The order is subdivided into three superfamilies: the Psittacoidea ('true' parrots), theCacatuoidea (cockatoos) and the Strigopoidea (New Zealand parrots). Parrots have a generally pantropical distribution with several species inhabiting temperate regions in theSouthern Hemisphere as well. The greatest diversity of parrots is found in South America andAustralasia.
Characteristic features of parrots include a strong, curved bill, an upright stance, strong legs, and clawed zygodactyl feet. Many parrots are vividly coloured, and some are multi-coloured. The plumage of cockatoos ranges from mostly white to mostly black, with a mobile crest of feathers on the tops of their heads. Most parrots exhibit little or no sexual dimorphism. They form the most variably sized bird order in terms of length.
The most important components of most parrots' diets are seeds, nuts, fruit, buds and other plant material. A few species sometimes eat animals and carrion, while the lories and lorikeetsare specialised for feeding on floral nectar and soft fruits. Almost all parrots nest in tree hollows(or nest boxes in captivity), and lay white eggs from which hatch altricial (helpless) young.
Parrots, along with ravens, crows, jays and magpies, are among the most intelligent birds, and the ability of some species to imitate human voices enhances their popularity as pets. Trappingwild parrots for the pet trade, as well as hunting, habitat loss and competition from invasive species, has diminished wild populations, with parrots being subjected to more exploitation than any other group of birds.[6] Measures taken to conserve the habitats of some high-profilecharismatic species have also protected many of the less charismatic species living in the same ecosystems.[7]
Origins and evolution

Blue-and-yellow Macaw eating a walnut held by a foot
Psittaciform diversity in South America and Australasia suggests that the order may have evolved in Gondwanaland, centred in Australasia. The scarcity of parrots in the fossil record, however, presents difficulties in supporting the hypothesis.
A single 15 mm (0.6 in) fragment from a large lower bill (UCMP 143274), found in deposits from the Lance Creek Formation in Niobrara County, Wyoming, had been thought to be the oldest parrot fossil and is presumed to have originated from the Late Cretaceous period, which makes it about 70 Ma (million years ago) Other studies suggest that this fossil is not from a bird, but from a caenagnathid theropod or a non-avian dinosaur with a birdlike beak.
It is now generally assumed that the Psittaciformes, or their common ancestors with several related bird orders, were present somewhere in the world around the Cretaceous–Paleogene extinction event (K-Pg extinction), some 65 Ma If so, they probably had not evolved theirmorphological autapomorphies yet, but were generalised arboreal birds, roughly similar (though not necessarily closely related) to today's potoos or frogmouths (see also Palaeopsittacusbelow). Though these birds (Cypselomorphae) are a phylogenetically challenging group, they seem at least closer to the parrot ancestors than, for example, the modern aquatic birds (Aequornithes). The combined evidence supported the hypothesis of Psittaciformes being "near passerines", i.e. the mostly land-living birds that emerged in close proximity to the K-Pg extinction. Indeed, analysis of transposable element insertions observed in the genomes of passerines and parrots, but not in the genomes of other birds, provides strong evidence that parrots are the sister group of passerines, forming a clade Psittacopasserae, to the exclusion of the next closest group, the falcons.[12]
Europe is the origin of the first presumed parrot fossils, which date from about 50 Ma. The climate there and then was tropical, consistent with the Paleocene-Eocene Thermal Maximum. Initially, a neoavian named Mopsitta tanta, uncovered in Denmark's Early Eocene Fur Formation and dated to 54 Ma, was assigned to the Psittaciformes; it was described from a single humerus.[13] However, the rather nondescript bone is not unequivocally psittaciform, and more recently it was pointed out that it may rather belong to a newly-discoveredibis of the genus Rhynchaeites, whose fossil legs were found in the same deposits.

Fossils assignable to Psittaciformes (though not yet the present-day parrots) date from slightly later in the Eocene, starting around 50 Ma. Several fairly complete skeletons of parrot-like birds have been found in England and Germany.[14] Some uncertainty remains, but on the whole it seems more likely that these are not direct ancestors of the modern parrots, but related lineages which evolved in the Northern Hemisphere and have since died out. These are probably not "missing links" between ancestral and modern parrots, but rather psittaciform lineages that evolved parallel to true parrots and cockatoos and had their own peculiar autapomorphies:
The earliest records of modern parrots date to about 23–20 Ma and are also from Europe. Subsequently, the fossil record—again mainly from Europe—consists of bones clearly recognisable as belonging to parrots of modern type. The Southern Hemisphere does not have nearly as rich a fossil record for the period of interest as the Northern, and contains no known parrot-like remains earlier than the early to middle Miocene, around 20 Ma. At this point, however, is found the first unambiguous parrot fossil (as opposed to a parrot-like one), an upper jaw which is indistinguishable from that of modern cockatoos. A few modern genera are tentatively dated to a Miocene origin, but their unequivocal record stretches back only some 5 million years (see genus articles for more).

The named fossil genera of parrots are probably all in the Psittacidae or close to its ancestry: * Archaeopsittacus (Late Oligocene/Early Miocene) * Xenopsitta (Early Miocene of Czechia) * Psittacidae gen. et spp. indet. (Bathans Early/Middle Miocene of Otago, New Zealand)—several species * Bavaripsitta (Middle Miocene of Steinberg, Germany) * Psittacidae gen. et sp. indet. (Middle Miocene of France)—erroneously placed in Pararallus dispar, includes "Psittacus" lartetianus
Some Paleogene fossils are not unequivocally accepted to be of psittaciforms: * Palaeopsittacus (Early – Middle Eocene of NW Europe)—caprimulgiform (podargid?) or quercypsittid? * "Precursor" (Early Eocene)—part of this apparent chimera seems to be of a pseudasturid or psittacid * Pulchrapollia (Early Eocene)—includes "Primobucco" olsoni—psittaciform (pseudasturid or psittacid)?
Molecular studies suggest that parrots evolved approximately 59 Ma (range 66–51 Ma) in Gondwanaland.[15] The three major clades of Neotropical parrots originated about 50 Ma (range 57–41 Ma).
Distribution and habitat

Parrots are found on all tropical and subtropical continents including Australia and Oceania,South Asia, Southeast Asia, Central America, South America and Africa. Some Caribbean and Pacific islands are home to endemic species. By far the greatest number of parrot species come from Australasia and South America. The lories and lorikeets range from Sulawesi and the Philippines in the north to Australia and across the Pacific as far as French Polynesia, with the greatest diversity being found in and around New Guinea. The subfamily Arinaeencompasses all the Neotropical parrots, including the Amazons, macaws and conures, and ranges from northern Mexico and the Bahamas to Tierra del Fuego in the southern tip of South America. The pygmy parrots, tribe Micropsittini, form a small genus restricted to New Guinea. The superfamily Strigopoidea contains three living species of aberrant parrots from New Zealand. The broad-tailed parrots, subfamily Platycercinae, are restricted to Australia, New Zealand and the Pacific islands as far eastwards as Fiji. The true parrot superfamily, Psittacoidea, includes a range of species from Australia and New Guinea to South Asia and Africa. The centre of cockatoo biodiversity is Australia and New Guinea, although some species reach the Solomon Islands (and one formerly occurred in New Caledonia), Wallaceaand the Philippines.
Several parrots inhabit the cool, temperate regions of South America and New Zealand. One, the Carolina Parakeet, lived in temperate North America, but was hunted to extinction in the early 20th century. Many parrots have been introduced to areas with temperate climates, and have established stable populations in parts of the United States (including New York City),] the United Kingdom,]Belgium] and Spain.
Few parrots are wholly sedentary or fully migratory. Most fall somewhere between the two extremes, making poorly understood regional movements, with some adopting an entirely nomadic lifestyle.[32]

Intelligence and learning

Studies with captive birds have given insight into which birds are the most intelligent. While parrots are able to mimic human speech, studies with the African Grey Parrot have shown that some are able to associate words with their meanings and form simple sentences (see Alexand N'kisi). Along with crows, ravens, and jays (family Corvidae), parrots are considered the most intelligent of birds. The brain-to body size ratio of psittacines and corvines is actually comparable to that of higher primates.[47] One argument against the supposed intelligent capabilities of bird species is that birds have a relatively small cerebral cortex, which is the part of the brain considered to be the main area of intelligence in other animals. However, birds use a different part of the brain, the medio-rostral neostriatum / hyperstriatum ventrale, as the seat of their intelligence. Not surprisingly, research has shown that these species tend to have the largest hyperstriata, and Dr Harvey J. Karten, a neuroscientist at the University of California, San Diego, who studied bird physiology, has discovered that the lower part of the avian brain is functionally similar to that in humans. Not only have parrots demonstrated intelligence through scientific testing of their language-using ability, but some species of parrot such as the Kea are also highly skilled at using tools and solving puzzles.
Learning in early life is apparently important to all parrots, and much of that learning is social learning. Social interactions are often practised with siblings, and in several species creches are formed with several broods, and these as well are important for learning social skills. Foraging behaviour is generally learnt from parents, and can be a very protracted affair. Supra-generalists and specialists are generally independent of their parents much quicker than partly specialised species which may have to learn skills over a long period of time as various resources become seasonally available. Play forms a large part of learning in parrots; it can be solitary, and related to motor skills, or social. Species may engage in play fights or wild flights to practice predator evasion. An absence of stimuli can retard the development of young birds, as demonstrated by a group of Vasa Parrots kept in tiny cages with domesticated chickens from the age of 3 months; at 9 months these birds still behaved in the same way as 3 month olds, but had adopted some chicken behaviour.] In a similar fashion captive birds in zoo collections or pets can, if deprived of stimuli, develop stereotyped behaviours and harmful behaviours like self plucking. Aviculturists working with parrots have identified the need for environmental enrichment to keep parrots stimulated.
Relationship with humans Humans and parrots have a complicated relationship. Economically they can be beneficial to communities as sources of income from the pet trade and are highly marketable tourism draws and symbols. But some species are also economically important pests, particularly some cockatoo species in Australia. Some parrots have also benefited from human changes to the environment in some instances, and have expanded their ranges alongside agricultural activity, but many species have declined as well.
There exist a number of careers and professions devoted to parrots. Zoos and aquariums employ keepers to care for and shape the behaviour of parrots. Some veterinarians who specialise in avian medicine will treat parrots exclusively. Biologists study parrot populations in the wild and help to conserve wild populations. Aviculturalists breed and sell parrots for the pet trade.
Tens of millions of parrots have been removed from the wild, and parrots have been traded in greater numbers and for far longer than any other group of wild animals. Many parrot species are still threatened by this trade as well as habitat loss, predation by introduced species, and hunting for food or feathers. Some parrot species are agricultural pests, eating fruits, grains, and other crops, but parrots can also benefit economies through birdwatching based ecotourism.

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