Mauritiussittich

Bestimmung

The echo parakeet is 34–42 cm (13–17 in) long and weighs 167–193 g (5.9–6.8 oz), which makes it smaller than the other, now extinct, Mauritian parrots. The wingspan is 49–54 cm (19–21 in), each wing is 177–190 mm (7.0–7.5 in) long, the tail is 164–200 mm (6.5–7.9 in), the culmen is 21–23 mm (0.83–0.91 in), and the tarsus is 20–22 mm (0.79–0.87 in). The female is somewhat smaller than the male on average. It is generally green, with a darker back and yellowish underside. The male is lighter and the female darker overall. It has two ring collars on the neck, which are incomplete, failing to meet at the back. The male has one black and one pink collar, which appears crescent shaped in side view, and has blue suffusion above it. The female has an indistinct black collar and a green collar, which becomes dark green across the cheeks and yellow-green at the back of the neck. The male has a black, narrow line running from the cere to the eye. The outer primary feathers of some males are tinged with blue. The upper bill of the adult male is bright red, the lower blackish brown, while the upper bill of the female is dark, almost black. The iris is yellow, varying from pale to greenish, but individuals with pink or white irides have also been noted. The skin around the eyes is orange, and the feet are grey, varying from greenish to blackish. The bill of the juvenile is red-orange, similar to that of the adult male, until two to three months after it fledges, when it changes to black, similar to that of the adult female. The immature is similar to the female.<p>Based on the single known specimen and contemporary accounts, it is believed the male of the extinct Réunion subspecies was generally similar to that of Mauritius, but differed in being slightly larger, each wing being 193 mm (7.6 in) long and the culmen 24.5 mm (0.96 in). The pink collar entirely encircled its neck, whereas it tapers out and leaves a gap at the back of the neck in the Mauritius subspecies. The Réunion subspecies also appears to have had darker lower parts. The echo parakeet is very similar to the related rose-ringed parakeet (which has been introduced to Mauritius, making confusion possible), though the green plumage of the former is darker and richer, its nape has a bluish wash, and its tail is greener above, and shorter. The female is similar to that of the rose-ringed parakeet though darker, and more emerald green. Unlike the echo parakeet, the rose-ringed parakeet does not display sexual dimorphism in beak colour. The echo parakeet is also stockier, and about 25% larger in body size and weight than the rose-ringed parakeet. The echo parakeet has comparatively shorter, broader, and more rounded wings than other Psittacula species, as well as a shorter and broader tail.<p>The echo parakeet has a wide range of vocalisations, and are most vocal before roosting in the evening. They vocalise all year, but more during the breeding season. The most common vocalisation is the contact call, a low, nasal squawk sounding like "chaa-chaa, chaa-chaa" (also transliterated as "chaa-choa" or "kaah"), which is emitted singly or in a fast series, about twice a second. The flight call is very similar to the contact call. There is a higher pitched excitement or alarm call which sounds like "chee-chee-chee-chee" three or four times a second, usually emitted during flight with shallow, rapid wing beats. When disturbed or frightened, it may give a short, sharp "ark" call. It emits more melodious chirrups and whistles while perched. A deep, quiet "werr-werr" and a "prr-rr-rr" purr has also been heard on two occasions from a female landing in a tree. A courtship call can be heard between September and December. They also "growl" when angry, in a similar way to other parrots. The voice of the echo parakeet is very different from that of the rose-ringed parakeet, which has higher, faster, and more "excited" sounding vocalisations, and their calls cannot be confused.

Taxonomie

Green parakeets were mentioned in the accounts of early travelers to the Mascarene Islands of Réunion and Mauritius. They were first recorded on Réunion in 1674 by the French traveler Sieur Dubois, and on Mauritius in 1732 by the French engineer Jean-François Charpentier de Cossigny. The green parakeets of Réunion were referred to as perruche à double collier ("double-collared parakeet") by the French naturalists Mathurin Jacques Brisson, in 1760, Comte de Buffon, in 1770–1783, and François Levaillant, in 1801–1805, who described them from specimens that reached France. In 1783, the Dutch naturalist Pieter Boddaert coined the scientific name Psittacus eques, based on a plate by the French artist François-Nicolas Martinet, which accompanied Buffon's account of the Réunion bird in his work Histoire Naturelle. The specific name eques is Latin for "horseman", and refers to the military colours of a French cavalryman. Martinet's plate was drawn after a specimen that was part of the collection in the Cabinet Aubry in Paris, and the plate is the type illustration. Whether the contemporary illustrations were based on live or stuffed specimens is unknown; though as all show different poses, this suggests several specimens existed if they were mounted. Neither is it clear if the descriptions from France were based on different or the same imported specimens nor how many reached Europe. Levaillant knew of two specimens, and as many as five may have existed.<p>The green parakeets of Mauritius and Réunion were usually treated together in historical literature, and their histories have consequently been muddled. In 1822, the British ornithologist John Latham listed the parakeet of Réunion (and "other parts of the same latitude") as a variety of the rose-ringed parakeet, which he referred to as Psittica torquata, based on a name coined by Brisson. In 1876, the British ornithologists and brothers Alfred and Edward Newton pointed out that the avifauna of Réunion and Mauritius were generally distinct from each other, and that this might, therefore, also be true of the parakeets. They suggested the new name Palaeornis echo for the Mauritian species (referring to Echo, a nymph in Greek mythology), while noting that it was very similar to the by-then extinct Réunion species (which retained the name Palaeornis eques). The Italian ornithologist Tommaso Salvadori united the two again in 1891, while giving only Mauritius as the habitat. In 1907, British zoologist Walter Rothschild supported the separation of the two species on account of the other birds of Réunion and Mauritius being distinct, while noting that how they differed was unknown. The American ornithologist James L. Peters listed the parakeet of Mauritius as a subspecies of the rose-ringed parakeet (Psittacula krameri) in 1937; P. k. echo. He thereby replaced the genus name Palaeornis with Psittacula, wherein he also classified other extant parakeets of Asia and Africa. In 1967, the American ornithologist James Greenway considered the parakeets of both Mauritius and Réunion to be subspecies of the rose-ringed parakeet, and found it probable that they differed from each other, unless the birds on Réunion had simply been introduced, though how was unknown.<p>In a 1987 book about Mascarene birds, the British ecologist Anthony S. Cheke stated that the parakeets of Mauritius and Réunion apparently belonged to the same species. In the same publication (a chapter which was one of the few studies of echo parakeet biology), British conservation biologist Carl G. Jones noted that the parakeets of the western Indian Ocean were probably derived from Indian Alexandrine parakeets (P. eupatria), losing the characteristics of that bird the farther they dispersed. Jones also reported an old parakeet skin, possibly from Réunion, in the Royal Museum of Scotland, Edinburgh (a study skin catalogued as specimen NMS.Z 1929.186.2). Originally part of the collection of the French taxidermist Louis Dufresne, it was bought by the University Museum of Edinburgh (which later became the Royal Museum) in 1819, along with the rest of his natural-history collection. The specimen's original label referred specifically to Levaillant's plate of the "perruche a double collier", illustrated by the French artist Jacques Barraband, which was meant to depict the parakeet of Réunion. Jones cautioned that the collection data of such early specimens may not always be reliable, and that the skin could possibly have come from Mauritius, instead. Whether the Edinburgh skin was the basis of Martinet's type illustration is unknown. Jones did not find the skin particularly different from those of living echo parakeets (or the old French descriptions), based on examination of photographs. He agreed with previous authors that the parakeets of Mauritius and Réunion belonged to the same species (P. eques, the oldest name), but that they should be kept separate at the subspecific level (as P. eques eques and P. eques echo), due to lack of further information about the extinct bird.<p>The living parakeet of Mauritius has been referred to by the English common name "echo parakeet" since the 1970s, based on the scientific name, and has also been called the Mauritius parakeet. The local Mauritian name is cateau vert, kato, or katover (derived from French). The Réunion population has been referred to as the Réunion parakeet and the Réunion ring-necked parakeet, but has also been subsumed under the common name of the echo parakeet.<p>In 2004, British geneticist Jim J. Groombridge and colleagues examined the DNA of Psittacula parakeets to determine their evolutionary relationships, and found that the echo parakeet had diverged from the Indian subspecies of rose-ringed parakeet (P. k. borealis) rather than the African subspecies (P. k. krameri). They found that the echo parakeet diverged relatively recently compared to other Psittacula species, between 0.7 and 2.0 million years ago, which appears to coincide with volcanic inactivity on Mauritius between 0.6 and 2.1 million years ago. The ancestors of the echo parakeet may, therefore, have migrated southwards from India across the Indian Ocean, and arrived at the time the island was formed. The authors cautioned that their interpretations were limited by the absence of DNA from the extinct Seychelles parakeet (P. wardi) and Newton's parakeet (P. exsul) from other Indian Ocean islands.<p>In 2007, based on morphological evidence, British palaeontologist Julian P. Hume found the echo parakeet to be more closely related to the Alexandrine parakeet than to the rose-ringed parakeet. He noted that the skeletal anatomy of the echo parakeet was mainly known from fossil bones, as it was the Mauritian parrot most commonly found in cave deposits, and that skeletons are rare in museum collections. Hume pointed out that many birds endemic to the Mascarene Islands are derived from South Asian ancestors, and that a South Asian provenance was probable for the parrots, as well. Sea levels were lower during the Pleistocene, so species island hopping to the isolated islands was possible. In spite of most mascarene parrots being poorly known, fossil remains show that they shared features such as enlarged heads and jaws, reduced pectoral elements, and robust leg elements. Hume suggested they shared a common origin within the Psittaculini radiation, based on morphological features and the fact that Psittacula parrots have managed to colonise many isolated islands in the Indian Ocean. In 2008, Cheke and Hume suggested that this group may have invaded the area several times, as many of the species were so specialised that they may have diverged on hot spot islands before the Mascarenes emerged from the sea.<p>A 2011 DNA study by British biologist Samit Kundu and colleagues found the echo parakeet samples grouped between two subspecies of the rose-ringed parakeet, P. k. krameri and P. k. borealis. They suggested that since some of the Indian Ocean island species had diverged early within their clades, including the echo parakeet within P. krameri, Africa and Asia may have been colonised from there rather than the other way around. They found the echo parakeet to have diverged between 3.7 and 6.8 million years ago, which, if correct, could imply that speciation had occurred before the formation of Mauritius. These researchers were unable to extract DNA from the Edinburgh specimen.<p>In 2015, British geneticist Hazel Jackson and colleagues managed to obtain DNA from a toe pad of the Edinburgh specimen and compare it with specimens from Mauritius. They found that within the P. krameri clade, Newton's parakeet from Rodrigues was ancestral to the Mauritius and Réunion parakeets, diverging from them 3.82 million years ago and that the latter two had diverged just 0.61 million years ago, differing by 0.2% from each other. The researchers concluded that the low level of divergence between the Mauritius and Réunion populations was consistent with them being distinct at the subspecific level. The following cladogram shows the phylogenetic position of the Mauritius and Réunion subspecies, according to Jackson and colleagues, 2015:<p>In 2018, the American ornithologist Kaiya L. Provost and colleagues found the Mascarene parrot (Mascarinus mascarinus) and Tanygnathus species to group within Psittacula, making that genus paraphyletic (an unnatural grouping), and stated this argued for breaking up the latter genus. To solve the issue, the German ornithologist Michael P. Braun and colleagues proposed in 2019 that Psittacula should be split into multiple genera. They placed the echo parakeet in the new genus Alexandrinus, along with its closest relatives, Newton's parakeet and the rose-ringed parakeet.<p>Cheke and the Dutch ornithologist Justin J. F. J. Jansen stated in 2016 that the Edinburgh specimen has no clear provenance information, and that it may have been collected from Mauritius (only one of Dufresne's other bird specimens was from Réunion, while several were from Mauritius). They noted that, unlike modern Mauritian specimens, the pink neck ring of the Edinburgh specimen continued uninterrupted around the back of the neck, similar to what Buffon and Levaillant described, but that from where the specimen Levaillant described was, was unclear. They stated that the genetic differences between the specimens were not necessarily subspecific, but because the Mauritian specimens were much more recent than the Edinburgh specimen, the similarity of the former specimens could have been due to a genetic bottleneck, resulting from a severe decline of the Mauritian population in the 19th century. They concluded that the default assumption should be that it came from Réunion. They also called attention to a usually overlooked, unlabelled sketch from around 1770 by French artist Paul Philippe Sanguin de Jossigny of a ring-necked parakeet with a collar encircling the neck, which they thought could have been from either island. In 2017, Hume agreed that the Edinburgh specimen could have come from Mauritius. He stated that the genetic differences could be due to variation within the population there, and pointed out that some other bird species migrate between Mauritius and Réunion.<p>Also in 2017, Australian ornithologist Joseph M. Forshaw agreed that the Mauritius and Réunion populations were subspecifically distinct and that the Edinburgh specimen was from Réunion, and should be designated the neotype of P. eques. The following year, Jones and colleagues, including authors of the DNA studies, Hume, and Forshaw, supported the identification of the Edinburgh specimen as a Réunion parakeet and the subspecific differentiation between the populations. They found that the specimen differed from all examined Mauritius specimens in having a complete pink collar, instead of having a gap at the back of the neck, a feature emphasised by Brisson, Buffon, and Levaillant in their descriptions of the Réunion parakeet, but not obvious in the photographs seen by Jones in the 1980s. Since populations on islands usually have lower genetic diversity than those on continents, they stated that the low level of differentiation between the Mauritius and Réunion specimens would be expected. They found it possible that Jossigny's drawing showed a Réunion parakeet.<p>In 2020, Jansen and Cheke pointed out that Marinet's plate that serves as the type illustration of P. eques differs considerably in colouration between copies (some have yellow on the upper breast while others do not, for example). They concluded that these were hand-coloured by different people after an unidentified master plate by Martinet, but since it cannot be established which of the copies that accurately represents the specimen they depicted, Jansen and Cheke found it safer to rely on the description by Brisson. In 2021, Jansen and Cheke found that the variation in plumage seen in males in Mauritius is wide enough to encompass that known from the descriptions, illustrations and skin from Réunion. They therefore concluded that the two populations belonged to a single species with no subspecies. They also found that there was no evidence to reliably confirm what island the Edinburgh skin was collected from, and that since it was unknown to the French encyclopaedists that echo parakeets also lived on Mauritius, birds matching their descriptions were assigned to Réunion by default.<p>A 2022 genetic study by the Brazilian ornithologist Alexandre P. Selvatti and colleagues confirmed the earlier studies in regard to the relationship between Psittacula, the Mascarene parrot, and Tanygnathus. They suggested that Psittaculinae originated in the Australo–Pacific region (then part of the supercontinent Gondwana), and that the ancestral population of the Psittacula–Mascarinus lineage were the first psittaculines in Africa by the late Miocene (8–5 million years ago), and colonised the Mascarenes from there.

Wissenschaftlicher Name

Psittacula eques

Autorität

(Boddaert, 1783)

Ordnung

Psittaciformes

Familie

Psittaculidae

Gattung

Psittacula

Verbreitung und Lebensraum

The echo parakeet is now restricted to forested areas of Mauritius with native vegetation, which covers less than 2% of Mauritius as of 2017, namely the Black River Gorges National Park in the southwest. They occupy only about 40 square kilometres (15 sq mi), and use about half of this area regularly. Within the park, there are four northern populations (in the Black River Gorges) and two southern (in Bel Ombre forest). In the upland forest, they prefer large, mature trees such as Canarium paniculatum, Syzygium contractum, Mimusops maxima, Labourdonnaisia sp. Other important feeding areas include lowland, intermediate and scrub forests. There are annual fluctuations in how often echo parakeets are seen in their habitats, which reflect population density. While the distribution of the species is tied to native forests, its numbers and distribution decreasing as these are destroyed, several early accounts indicate its distribution was always thin. The echo parakeet also formerly occurred in heavily degraded areas, which were therefore only lightly wooded. Though now sedentary, the parakeet may have moved between areas seasonally in search for food; if cyclones had stripped trees of fruits, for example.<p>A 2012 genetic study by the British zoologist Claire Raisin and colleagues showed that before the programme of captive breeding, echo parakeets from the more isolated Bel Ombre regions in the southern part of Black River Gorges National Park were genetically different from the rest of the population, but that the genetic diversity was dispersed across the bird's range after the period of intense managing, when birds were moved between areas. The genetic differentiation between the populations may originally have been due to forest clearing, which isolated them from each other.

Zugverhalten

Standvogel

Verhalten

Zugverhalten: Standvogel.

Schutzstatus

Bestandstrend: zunehmend.

Bestandstrend

zunehmend