Newton's parakeet

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Newton's parakeet
Life drawing
by Paul Jossigny, 1770s

Extinct (ca. 1875)  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Family: Psittaculidae
Genus: Psittacula
Species:
†P. exsul
Binomial name
†Psittacula exsul
(Newton, 1872)
Location of Rodrigues
Synonyms
  • Palaeornis exsul Newton, 1872

Newton's parakeet (Psittacula exsul), also known as the Rodrigues parakeet or Rodrigues ring-necked parakeet, is an

Mascarene island of Rodrigues in the western Indian Ocean. Several of its features diverged from related species, indicating long-term isolation on Rodrigues and subsequent adaptation. The rose-ringed parakeet of the same genus is a close relative and probable ancestor. Newton's parakeet may itself have been ancestral to the endemic parakeets of nearby Mauritius and Réunion
.

Around 40 centimetres (16 in) long, Newton's parakeet was roughly the size of a rose-ringed parakeet. Its

slate blue in colour, which is unusual in Psittacula, a genus containing mostly green species. The male had stronger colours than the female and possessed a reddish instead of black beak, but details of a mature male's appearance are uncertain; only one male specimen is known, and it is believed to be immature. Mature males might have possessed red patches on the wing like the related Alexandrine parakeet. Both sexes had a black collar running from the chin to the nape, but this was clearer in the male. The legs were grey and the iris yellow. Some 17th-century accounts indicate that some members of the species were green, which would suggest that both blue and green colour morphs occurred, but no definitive explanation exists for these reports. Little is known about its behaviour in life, but it may have fed on the nuts of the bois d'olive tree, along with leaves. It was very tame and was able to mimic speech
.

Newton's parakeet was first written about by the French

Huguenot François Leguat in 1708 and was only mentioned a few times by other writers afterwards. The specific name "exsul" is a reference to Leguat, who was exiled from France. Only two life drawings exist, both of a single specimen held in captivity in the 1770s. The species was scientifically described in 1872, with a female specimen as the holotype. A male, the last specimen recorded, was collected in 1875, and these two specimens are the only ones that exist today. The bird became scarce due to deforestation and perhaps hunting, but it was thought to have been finally wiped out by a series of cyclones
and storms that hit Rodrigues in the late 19th century. Speculation about the possible survival of the species, though unfounded, lasted as late as 1967.

Taxonomy

Illustration of the female holotype specimen, by John Gerrard Keulemans, 1875

Newton's parakeet was first recorded by

1761 transit of Venus.[2][3][4]

In 1871, George Jenner, the British

Cambridge University Museum as specimen UMZC 18/Psi/67/h/1.[3]

A. Newton requested further specimens, especially males, but in 1875 he finally published a plate of the female, lamenting that no male specimens could be found. Tafforet's 1726 account had been rediscovered the previous year, and A. Newton noted that it confirmed his assumption that the male would turn out be much more colourful than the female. Newton's collector, the English naturalist Henry H. Slater, had seen a live Newton's parakeet the year before, but was not carrying a gun at the time.[6][7] On 14 August 1875, William Vandorous shot a male specimen.[8] It may have been the same specimen Slater had observed. It was subsequently sent to E. Newton by William J. Caldwell.[9] This is the paratype of the species, numbered UMZC 18/Psi/67/h/2 and housed in the Cambridge Museum.[3]

In 1876, the Newton brothers noted that they had expected the male would be adorned with a red patch on the wing, but that the absence of this indicated it was immature. They still found it more beautiful than the female.

Palaeornis with Psittacula, wherein he also classified other extant parakeets of Asia and Africa.[11]

Evolution

Sternum and mandible extracted from the female specimen, 1875

Based on

derived features of Newton's parakeet indicates it had long been isolated on Rodrigues.[3][12]

Many endemic Mascarene birds, including the

hotspot islands before the Mascarenes emerged from the sea. Other members of the genus Psittacula from the Mascarenes include the extant echo parakeet (Psittacula eques echo) of Mauritius, as well as its extinct Réunion subspecies (Psittacula eques eques), and the Mascarene grey parakeet (Psittacula bensoni) of both Mauritius and Réunion.[13]

A 2011

phylogeny was unable to include Newton's parakeet, as no viable DNA could be extracted.[14] A 2015 genetic study by the British geneticist Hazel Jackson and colleagues included viable DNA from the toe-pad of the female Newton's parakeet specimen. It was found to group within a clade of rose-ringed parakeet subspecies (from Asia and Africa), which it had diverged from 3.82 million years ago. Furthermore, Newton's parakeet appeared to be ancestral to the parakeets of Mauritius and Réunion. The cladogram accompanying the study is shown below:[15]

The echo parakeet of nearby Mauritius, the closest living relative

Psittacula krameri parvirostris (Abyssinian rose-ringed parakeet)

Psittacula krameri manillensis (Indian rose-ringed parakeet)

Psittacula krameri borealis (Boreal rose-ringed parakeet)

Psittacula eques echo
(echo parakeet)

Psittacula eques eques (Réunion parakeet)

Psittacula exsul (Newton's parakeet)

Psittacula krameri krameri
(African rose-ringed parakeet)

In 2018, the American ornithologist Kaiya L. Provost and colleagues found the

Alexandrinus, along with its closest relatives, the echo parakeet and the rose-ringed parakeet.[17]

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.[18]

Description

Jossigny's other 1770s life drawing

Newton's parakeet was about 40 cm (16 in) long – roughly the size of the rose-ringed parakeet.

cere. It had a broad black collar running from the chin to the nape, where it became gradually narrower. The underside of the tail was greyish, the upper beak was dark reddish brown, and the mandible was black. The legs were grey and the iris yellow. The female was similar but had a greyer head and a black beak. The black collar was not so prominent as that of the male and did not extend to the back of the neck.[19]

The general appearance of Newton's parakeet was similar to the extant Psittacula species, including the black collar, but the bluish grey colouration set it apart from other members of its genus, which are mostly green.[19] It differed from its Mascarene relatives in some skeletal details, including in that the internal margin of the mandibular symphysis (where the two halves of the lower jaw connected) was oval instead of square-shaped when seen from above, and in that the upper end of the humerus (upper arm bone) was less expanded than in the Mascarene grey parakeet and the echo parakeet.[3]

Possible colour variation

The French naturalist Philibert Commerson received a live specimen on Mauritius in the 1770s and described it as "greyish blue". French artist Paul Philippe Sanguin de Jossigny made two illustrations of this specimen, the only known depictions of Newton's parakeet in life, unpublished until 2007.[3] Though both existing specimens are blue, some early accounts from Rodrigues have caused confusion over the colouration of the plumage.[19] One of these is Leguat's following statement:

Extinct Birds
, based on his 1875 illustration of the female specimen

There are abundance of green and blew Parrets, they are of a midling and equal bigness; when they are young, their Flesh is as good as young Pigeons.[3]

If the green parrots Leguat referred to were not the

colour morph of Newton's parakeet, as Hume has suggested. As A. Newton observed in his original description, some feathers of the female specimen display both blue and green tinges, depending on the light. This may explain some of the discrepancies.[3] According to Fuller, the green parrots mentioned could also instead have been storm-blown members of Psittacula species from other islands, that survived on Rodrigues for a short time.[19]

The two existing specimens were originally preserved in alcohol, but though this can discolour specimens, it is not probable that it could turn green to blue.

collecting bias, as unusually coloured specimens are more likely to be collected than those of normal colour.[20]

Tafforet also described what appears to be green Newton's parakeets, but the issue of colouration was further complicated by the mention of red plumage:

The parrots are of three kinds, and in quantity ... The second species [mature male Newton's parakeet?] is slightly smaller and more beautiful, because they have their plumage green like the preceding [Rodrigues Parrot], a little more blue, and above the wings a little red as well as their beak. The third species [Newton's parakeet] is small and altogether green, and the beak black.[3]

In 1987, the British ecologist

grey-headed lovebirds (Agapornis canus) by A. Newton, but Cheke did not find this likely, as their beaks are grey.[21] Pingré also mentioned green birds, perhaps with some red colours, but his account is partially unintelligible and therefore ambiguous. A red shoulder patch is also present on the related Alexandrine parakeet.[3] None of the existing Newton's parakeet specimens have red patches. Fuller suggested the single known male specimen may have been immature, judged on the colour of its beak, and this may also explain the absence of the red patch.[19] When Psittacula are bred by aviculturalists, blue is easily produced from green; the production of blue may suppress red colouration, so blue morphs may have lacked the red patch.[3]

Behaviour and ecology

Map of Rodrigues, decorated with solitaires
Map of human settlement on Rodrigues
François Leguat's 1708 maps of Rodrigues and his settlement

Almost nothing is known about the behaviour of Newton's parakeet, but it is probable that it was similar to that of other members of its genus. Leguat mentioned that the parrots of the island ate the nuts of the bois d'olive tree (Cassine orientalis). Tafforet also stated that the parrots ate the seeds of the bois de buis shrub (Fernelia buxifolia), which is endangered today, but was common all over Rodrigues and nearby islets during his visit.[3] Newton's parakeet may have fed on leaves as the related echo parakeet does. The fact that it survived long after Rodrigues had been heavily deforested shows that its ecology was less vulnerable than that of, for example, the Rodrigues parrot.[13]

Leguat and his men were hesitant to hunt the parrots of Rodrigues because they were so tame and easy to catch.[12] Leguat's group took a parrot as a pet and were able to teach it to speak:

Hunting and Fishing were so easie to us, that it took away from the Pleasure. We often delighted ourselves in teaching the Parrots to speak, there being vast numbers of them. We carried one to Maurice Isle [Mauritius], which talk'd French and Flemish.[13]

The authors of the 2015 study which resolved the phylogenetic placement of the Mascarene island parakeets suggested that the echo parakeet of Mauritius would be a suitable

ecological replacement for the Réunion parakeet and Newton's parakeet, due to their close evolutionary relationship. The echo parakeet was itself close to extinction in the 1980s, numbering only twenty individuals, but has since recovered, so introducing it to the nearby islands could also help secure the survival of this species.[15]

Many other species endemic to Rodrigues became extinct after humans arrived, and the island's ecosystem remains heavily damaged. Forests had covered the entire island before humans arrived, but very little forestation can be seen today. Newton's parakeet lived alongside other recently extinct birds such as the Rodrigues solitaire, the Rodrigues parrot, the Rodrigues rail, the Rodrigues starling, the Rodrigues scops owl, the Rodrigues night heron, and the Rodrigues pigeon. Extinct reptiles include the domed Rodrigues giant tortoise, the saddle-backed Rodrigues giant tortoise, and the Rodrigues day gecko.[13]

Extinction

Statues in Hungary of Newton's parakeet and the also extinct broad-billed parrot of Mauritius

Of the roughly eight parrot species endemic to the Mascarenes, only the echo parakeet has survived. The others were likely all made extinct by a combination of excessive hunting and deforestation by humans.[3] Leguat stated that Newton's parakeet was abundant during his stay. It was still common when Tafforet visited in 1726, but when Pingré mentioned it in 1761, he noted that the bird had become scarce. It was still present on southern islets off Rodrigues (Isle Gombrani), along with the Rodrigues parrot. After this point, much of Rodrigues was severely deforested and used for livestock.[3]

According to early accounts praising its flavour, it appears visitors commonly ate Newton's parakeet.[13] Several individuals would likely be needed to provide a single meal, owing to the bird's small size.[19] Pingré stated:

The perruche [Newton's parakeet] seemed to me much more delicate [than the flying-fox]. I would not have missed any game from France if this one had been commoner in Rodrigues; but it begins to become rare. There are even fewer perroquets [Rodrigues parrots], although there were once a big enough quantity according to François Leguat; indeed a little islet south of Rodrigues still retains the name Isle of Parrots [Isle Pierrot].[3]

According to government surveyor Thomas Corby, Newton's parakeet may still have been fairly common in 1843. Slater reported that he saw a single specimen in southwestern Rodrigues during his three-month stay to observe the

1874 Transit of Venus, and assistant colonial secretary William J. Caldwell saw several specimens in 1875 during his own three-month visit. The male that he received in 1875 and gave to Newton is the last recorded member of the species. A series of cyclones struck the following year and may have devastated the remaining population.[3] Further severe storms hit in 1878 and 1886, and since few forested areas were left by this time, there was little cover to protect any remaining birds. The male could, therefore, have been the last of the species alive.[13]

There were unfounded rumours of its continued existence until the beginning of the 20th century.[13] In 1967, the American ornithologist James Greenway stated that an extremely small population might still survive on small offshore islets, since this is often the last refuge of endangered birds.[22] The Mauritian ornithologist France Staub stated in 1973 that his visits to Rodrigues the previous seven years confirmed the bird was extinct.[23] Hume concluded in 2007 that the islets were probably too small to sustain a population.[3]

References

  1. doi:10.2305/IUCN.UK.2016-3.RLTS.T22685465A93074571.en
    .
  2. ^ Leguat, F. (1891). Oliver, S. P. (ed.). The voyage of François Leguat of Bresse, to Rodriguez, Mauritius, Java, and the Cape of Good Hope. Vol. 1. London: Hakluyt Society. pp. 84–85.
  3. ^
    doi:10.11646/zootaxa.1513.1.1
    .
  4. ^ Newton, A. (1875). "Additional evidence as to the original fauna of Rodriguez". Proceedings of the Zoological Society of London. 1875: 39–43.
  5. doi:10.1111/j.1474-919X.1872.tb05858.x
    .
  6. doi:10.1111/j.1474-919X.1875.tb05978.x
    .
  7. ^ Cheke, A. S. (2019). "Unpublished material from the Transit of Venus expedition to Rodrigues in 1874 - Henry Slater's sketchbook and notes on the birds of Rodrigues". Journal of the Royal Society of Arts & Sciences of Mauritius. 1: 48–56.
  8. ^
    doi:10.1111/j.1474-919X.1876.tb06925.x
    .
  9. S2CID 128901896
    .
  10. ^ Rothschild, W. (1907). Extinct Birds. London: Hutchinson & Co. p. 65.
  11. S2CID 41950882
    .
  12. ^
    ISBN 978-1-4081-5725-1
    .
  13. ^
    ISBN 978-0-7136-6544-4
    .
  14. PMID 22019932
    .
  15. ^
    doi:10.1111/ibi.12275
    .
  16. S2CID 52995298
    .
  17. S2CID 91969786
    .
  18. doi:10.1111/jbi.14466
    .
  19. ^
    ISBN 978-0-670-81787-0
    .
  20. ^ Hume, J. P.; van Grouw, H. (2014). "Colour aberrations in extinct and endangered birds". Bulletin of the British Ornithologists' Club. 134: 168–193.
  21. ISBN 978-0-521-11331-1
    .
  22. ISBN 978-0-486-21869-4
    .
  23. OCLC 6800045
    .

External links
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