PARROTs
Parrots, also known as psittacines are birds of the roughly 393 species in 92 genera that make up the orderPsittaciformes, found in most tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoidea ("true" parrots), the Cacatuoidea (cockatoos), and the Strigopoidea (New Zealand parrots). Parrots have a generally pantropical distribution with several species inhabiting temperate regions in the Southern Hemisphere, as well. The greatest diversity of parrots is 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. 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 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. Trapping wild parrots for the pet trade, as well as hunting, habitat loss, and competition frominvasive 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 (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 million years ago (Mya). Other studies suggest that this fossil is not from a bird, but from a caenagnathidtheropod 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 66 Mya. If so, they probably had not evolved theirmorphological autapomorphies yet, but were generalised arboreal birds, roughly similar (though not necessarily closely related) to today'spotoos 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, thefalcons.
Europe is the origin of the first undeniable parrot fossils, which date from about 50 Mya. 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 Mya, was assigned to the Psittaciformes; it was described from a single humerus. 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.
The feathers of a yellow-headed amazon: The blue component of the green colouration is due to light scattering, while the yellow is due to pigment.
Fossils assignable to Psittaciformes (though not yet the present-day parrots) date from slightly later in the Eocene, starting around 50 Mya. Several fairly complete skeletons of parrot-like birds have been found in England and Germany. 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:
Psittacopes (Early/Middle Eocene of Geiseltal, Germany)—basal[citation needed]
Serudaptus—pseudasturid or psittacid[citation needed]
Pseudasturidae (Halcyornithidae may be correct name)
Pseudasturides – formerly Pseudastur
Vastanavidae
Vastanavis (Early Eocene of Vastan, India)
Quercypsittidae
Quercypsitta (Late Eocene)
The earliest records of modern parrots date to about 23–20 Mya 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 Mya. 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).
Fossil skull of a presumed parrot relative from the Eocene Green River Formation in Wyoming
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)[citation needed] or quercypsittid[citation needed]
"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)[citation needed]
Molecular studies suggest that parrots evolved approximately 59 Mya (range 66–51 Mya) in Gondwanaland. The three major clades of Neotropical parrots originated about 50 Ma (range 57–41 Ma).
Phylogeny.
Parrots
Psittacoidea
Cacatuoidea
Strigopoidea
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. 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 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. Trapping wild parrots for the pet trade, as well as hunting, habitat loss, and competition frominvasive 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 (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 million years ago (Mya). Other studies suggest that this fossil is not from a bird, but from a caenagnathidtheropod 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 66 Mya. If so, they probably had not evolved theirmorphological autapomorphies yet, but were generalised arboreal birds, roughly similar (though not necessarily closely related) to today'spotoos 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, thefalcons.
Europe is the origin of the first undeniable parrot fossils, which date from about 50 Mya. 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 Mya, was assigned to the Psittaciformes; it was described from a single humerus. 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.
The feathers of a yellow-headed amazon: The blue component of the green colouration is due to light scattering, while the yellow is due to pigment.
Fossils assignable to Psittaciformes (though not yet the present-day parrots) date from slightly later in the Eocene, starting around 50 Mya. Several fairly complete skeletons of parrot-like birds have been found in England and Germany. 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:
Psittacopes (Early/Middle Eocene of Geiseltal, Germany)—basal[citation needed]
Serudaptus—pseudasturid or psittacid[citation needed]
Pseudasturidae (Halcyornithidae may be correct name)
Pseudasturides – formerly Pseudastur
Vastanavidae
Vastanavis (Early Eocene of Vastan, India)
Quercypsittidae
Quercypsitta (Late Eocene)
The earliest records of modern parrots date to about 23–20 Mya 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 Mya. 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).
Fossil skull of a presumed parrot relative from the Eocene Green River Formation in Wyoming
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)[citation needed] or quercypsittid[citation needed]
"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)[citation needed]
Molecular studies suggest that parrots evolved approximately 59 Mya (range 66–51 Mya) in Gondwanaland. The three major clades of Neotropical parrots originated about 50 Ma (range 57–41 Ma).
Phylogeny.
Parrots
Psittacoidea
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Cacatuoidea
Strigopoidea
-_Wellington_-NZ-8-2c.jpg)
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