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Parrot

Parrots, also known as are birds of the roughly 372 species in 86 genera that make up the order found in most tropical and subtropical regions. The order is subdivided into three super families: the Psittacoidea, the Cacatuoidea (cockatoos) and the Strigopoidea (New Zealand parrots). Parrots have a generally pan tropical distribution with several species inhabiting temperate regions in the Southern Hemisphere as well. The greatest diversity of parrots is in South America and Australasia.

Characteristic features of parrots include a strong, curved bill, an upright stance, strong legs, and clawed zygodactyls feet. Many parrots are vividly coloured, and some are multi-colored. 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 lorikeets are specialized 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 antiracial (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. Trapping wild 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. Measures taken to conserve the habitats of some high-profile charismatic species have also protected many of the less charismatic species living in the same ecosystems.

Taxonomy Origins and evolution

Blue-and-yellow macaw eating a walnut held in its 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 confirming the hypothesis.

A single 15 mm (0.6 in) fragment from a large lower bill , 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–Paleocene extinction event (K-Pg extinction), some 66 Ma. If so, they probably had not evolved their morphological autapomorphies yet, but were generalized arboreal birds, roughly similar (though not necessarily closely related) to today’s photos or frogmouths (see also Palaeopsittacus below). 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.

Europe is the origin of the first undeniable 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 hummers. However, the rather nondescript bone is not unequivocally psittaciform, and more recently it was pointed out that it may rather belong to a newly discovered ibis of the genus Rhynchaeites, whose fossil legs were found in the same deposits.

Morphology

Glossy black cockatoo showing the parrot’s strong bill, clawed feet, and sideways positioned eyes Extant species range in size from the buff-faced pygmy parrot, at under 10 g (0.4 oz) in weight and 8 cm (3.1 in) in length, to the hyacinth macaw, at 1 m (3.3 ft) in length, and the kakapo, at 4.0 kg (8.8 lb) in weight. Among the superfamilies, the three extant Strigopoidea species are all large parrots, and the cockatoos tend to be large birds as well. The Psittacoidea parrots are far more variable, ranging the full spectrum of sizes shown by the family.

The most obvious physical characteristic is the strong, curved, broad bill. The upper mandible is prominent, curves downward, and comes to a point. It is not fused to the skull, which allows it to move independently, and contributes to the tremendous biting pressure the birds are able to exert. The lower mandible is shorter, with a sharp, upward-facing cutting edge, which moves against the flat portion of the upper mandible in an anvil-like fashion. There are touch receptors along the inner edges of the keratinized bill, which are collectively known as the “bill tip organ”, allowing for highly dexterous manipulations. Seed-eating parrots have a strong tongue (containing similar touch receptors to those in the bill tip organ), which helps to manipulate seeds or position nuts in the bill so that the mandibles can apply an appropriate cracking force. The head is large, with eyes positioned high and laterally in the skull, so the visual field of parrots are unlike any other birds. Without turning its head, a parrot can see from just below its bill tip, all above its head, and to quite far behind its head. Parrots also have quite a wide frontal binocular field for a bird, although this is nowhere near as large as primate binocular visual fields.

Parrots have strong zygodactyls feet with sharp, elongated claws, which are used for climbing and swinging. Most species are capable of using their feet to manipulate food and other objects with a high degree of dexterity, in a similar manner to a human using his hands. A study conducted with Australian parrots has demonstrated that they exhibit “handedness”—that is a distinct preference with regards to the foot used to pick up food, with adult parrots being almost exclusively “left-footed” or “right footed”, and with the prevalence of each preference within the population varying from species to species.

Cockatoo species have a mobile crest of feathers on the top of their heads which can be raised for display, and retracted. No other parrots can do so, but the Pacific lorikeets in the genera Vini and Phigys are able to ruffle the feathers of the crown and nape and the red-fan parrot (or hawk-headed parrot) has a prominent feather neck frill which can be raised and lowered at will. The predominant colour of plumage in parrots is green, though most species have some red or another colour in small quantities. Cockatoos are the main exception to this, having lost the green and blue plumage colors in their evolutionary history they are now predominately black or white with some red, pink or yellow. Strong sexual dimorphism in plumage is not typical among parrots, with some notable exceptions, the most striking being the eclectus parrot.

Distribution and habitat

Most parrot species are tropical but a few species, like this austral parakeet, range deeply into temperate zones

See also: List of Psittaciformes by population

Parrots are found on all tropical and subtropical continents and regions 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 Adriane encompasses all the Geotropically parrots, including the amazons, macaws and course, 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 super family, 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), Wallace and 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, as well as in Greece.

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.

Behavior

There are numerous challenges in studying wild parrots, as they are difficult to catch and once caught they are difficult to mark. Most wild bird studies rely on banding or wing tagging, but parrots chew off such attachments. Parrots also tend to range widely and consequently there are many gaps in knowledge of their behaviour. Some parrots have a strong, direct flight. Most species spend much of their time perched or climbing in tree canopies. They often use their bills for climbing by gripping or hooking on branches and other supports. On the ground parrots often walk with a rolling gait.

Diet

File:Yellow-tailed Black-Cockatoo kobble08.oggPlay media A yellow-tailed black cockatoo using its strong bill to search for grubs A white-eyed parakeet couple eating queen palm seeds. Parrots have curved and strong beaks that can break very hard seeds. The diet of parrots consists of seeds, fruit, nectar, pollen, buds, and sometimes arthropods and other animal prey. The most important of these for most true parrots and cockatoos are seeds; the evolution of the large and powerful bill can be explained primarily as an adaptation to opening and consuming seeds. All true parrots except the Pesquet’s parrot employ the same method to obtain the seed from the husk; the seed is held between the mandibles and the lower mandible crushes the husk, whereupon the seed is rotated in the bill and the remaining husk is removed. A foot is sometimes used to help holding large seeds in place. Parrots are seed predators rather than seed dispersers; and in many cases where species are recorded as consuming fruit they are only eating the fruit to get at the seed. As seeds often have poisons to protect them, parrots are careful to remove seed coats and other fruit parts which are chemically well defended, prior to ingestion. Many species in the Americas, Africa, and Papua New Guinea consume clay which both releases minerals and absorbs toxic compounds from the gut.

Parrots at a clay lick in Ecuador.

The lories and lorikeets, hanging parrots and swift parrot are primarily nectar and pollen consumers, and have tongues with brush tips to collect this source of food, as well as some specialised gut adaptations to accommodate this diet. Many other species also consume nectar as well when it becomes available.

Breeding

Although there are a few exceptions, parrots are monogamous breeders which nest in cavities and hold no territories other than their nesting sites. The pair bonds of the parrots and cockatoos are strong and a pair remains close even during the non-breeding season, even if they join larger flocks. As with many birds, pair bond formation is preceded by courtship displays; these are relatively simple in the case of cockatoos. In Psittacidae parrots common breeding displays, usually undertaken by the male, include slow deliberate steps known as a “parade” or “stately walk” and the “eye-blaze”, where the pupil of the eye constricts to reveal the edge of the iris. Allopreening is used by the pair to help maintain the bond. Cooperative breeding, where birds other than the breeding pair help the pair raise the young and is common in some bird families, is extremely rare in parrots, and has only unambiguously been demonstrated in the El Oro parakeet and the golden parakeet (which may also exhibit polyamorous, or group breeding, behaviour with multiple females contributing to the clutch). The vast majority of parrots are, like this feral rose-ringed parakeet, cavity nesters.

Only the monk parakeet and five species of Agapornis lovebird build nests in trees, and three Australian and New Zealand ground parrots nest on the ground. All other parrots and cockatoos nest in cavities, either tree hollows or cavities dug into cliffs, banks or the ground. The use of holes in cliffs is more common in the Americas. Many species use termite nests, possibly to reduce the conspicuousness of the nesting site or to create a favorable microclimate. In most cases both parents participate in the nest excavation. The length of the burrow varies with species, but is usually between 0.5–2 m (1.6–6.6 ft) in length. The nests of cockatoos are often lined with sticks, wood chips and other plant material. In the larger species of parrot and cockatoo the availability of nesting hollows may be limited, leading to intense competition for them within the species and between species, as well as with other bird families. The intensity of this competition can limit breeding success in some cases. Some species are colonial, with the burrowing parrot nesting in colonies up to 70,000 strong. Coloniality is not as common in parrots as might be expected, possibly because most species adopt old cavities rather than excavate their own.

The eggs of parrots are white. In most species the female undertakes all the incubation, although incubation is shared in cockatoos, the blue lorikeet, and the vernal hanging parrot. The female remains in the nest for almost all of the incubation period and is fed both by the male and during short breaks. Incubation varies from 17 to 35 days, with larger species having longer incubation periods. The newly born young are altricial, either lacking feathers or with sparse white down. The young spend anything from three weeks to four months in the nest, depending on species, and may receive parental care for several months thereafter.

As typical of K-selected species, the macaws and other larger parrot species have low reproductive rates. They require several years to reach maturity, produce one or very few young per year, and do not necessarily breed every year.

Intelligence and learning

Sun conure demonstrating parrots’ puzzle-solving skills

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 Alex and 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. 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 HVC, as the seat of their intelligence. Research has shown that these species tend to have the largest hyperstriata, and 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.

Sound imitation and speech

Main article: Talking bird

See also: Animal language

File:Amazon edited.oggPlay media

Video of an orange-winged amazon saying “Hello” having been prompted by some people

Many parrots can imitate human speech or other sounds. A study by Irene Pepperberg suggested a high learning ability in an African grey parrot named Alex. Alex was trained to use words to identify objects, describe them, count them, and even answer complex questions such as “How many red squares?” with over 80% accuracy. N’kisi, another African grey, has been shown to have a vocabulary of approximately a thousand words, and has displayed an ability to invent as well as use words in context and in the correct tense.

Parrots do not have vocal cords, so sound is accomplished by expelling air across the mouth of the bifurcated trachea. Different sounds are produced by changing the depth and shape of the trachea. African grey parrots of all subspecies are known for their superior ability to imitate sounds and human speech. This ability has made them prized as pets from ancient times to the present. In the Masnavi, written by Rumi of Persia in 1250, the author describes an ancient method for training parrots to speak.

Although most parrot species are able to imitate, some of the amazon parrots are generally regarded as the next-best imitators and speakers of the parrot world. The question of why birds imitate remains open, but those that do often score very high on tests designed to measure problem solving ability. Wild African grey parrots have been observed imitating other birds. Most other wild parrots have not been observed imitating other species.

Relationship with humans

File:Amazona aestiva -The Parrot Zoo, Friskney, Lincolnshire, England -laughing-8a.ogvPlay media Video of a blue-fronted amazon mimicking a human laughing 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 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.

Culture

Moche parrot. 200 A.D. Larco Museum Collection Lima, Peru Parrots have featured in human writings, story, art, humor, religion and music for thousands of years. From Aesop’s fable “The parrot and the cat” and the Roman poet Ovid’s “The Dead Parrot”(Latin), (English) to Monty Python’s “Dead Parrot Sketch” millennia later, parrots have existed in the consciousness of many cultures. Recent books about parrots in human culture include Parrot Culture.

In ancient times and current, parrot feathers have been used in ceremonies, and for decoration. The “idea” of the parrot has been used to represent the human condition in medieval literature such as the bestiary. They also have a long history as pets.

In Polynesian legend as current in the Marquesas Islands, the hero Laka/Aka is mentioned as having undertaken a long and dangerous voyage to Aotona in what are now the Cook Islands, to obtain the highly prized feathers of a red parrot as gifts for his son and daughter. On the voyage a hundred out of his 140 rowers died of hunger on their way, but the survivors reached Aotona and captured enough parrots to fill 140 bags with their feathers. By at least some versions, the feathers were plucked off living parrots without killing them.

Macaws, like other parrots, mate for life Currently parrots feature in many media. There are magazines devoted to parrots as pets, and to the conservation of parrots. Fictional films include Paulie and Rio, and documentaries include The Wild Parrots of Telegraph Hill.

Parrots have also been considered sacred. The Moche people of ancient Peru worshipped birds and often depicted parrots in their art. Parrots are used as symbols of nations and nationalism. A parrot is found on the flag of Dominica. The St. Vincent parrot is the national bird of St. Vincent and the Grenadines, a Caribbean nation.

Parrots are popular in Buddhist scripture and there are many writings about them. For example, Amitābha once changed itself into a parrot to aid in converting people. Another old story tells how after a forest caught fire, the parrot was so concerned it carried water to try and put out the flames. The ruler of heaven was so moved upon seeing the parrot’s act, that he sent rain to put out the fire. In Chinese Buddhist iconography, a parrot is sometimes depicted hovering on the upper right side Guan Yin clasping a pearl or prayer beads in its beak.

Sayings about parrots colour the modern English language. The verb “parroting” can be found in the dictionary, and means “to repeat by rote.” There are also clichés such as the British expression “sick as a parrot”; although this refers to extreme disappointment rather than illness, it may originate from the disease of psittacosis which can be passed to humans. The first occurrence of a related expression is in Aphra Behn’s 1681 play The False Count.

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