Broad-billed parrot

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Broad-billed parrot
Sketch of two broad-billed parrots
Sketch of two individuals in the Gelderland ship's journal, 1601

Extinct (by 1693)  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Family: Psittaculidae
Genus: †Lophopsittacus
Newton, 1875
Species:
†L. mauritianus
Binomial name
†Lophopsittacus mauritianus
(Owen, 1866)
Map showing former range of the broad-billed parrot
Location of Mauritius in blue
Synonyms
  • Psittacus mauritianus Owen, 1866

The broad-billed parrot or raven parrot (Lophopsittacus mauritianus) is a large

subfossil mandible in 1866, but this was not linked to the old accounts until the rediscovery of a detailed 1601 sketch that matched both the subfossils and the accounts. It is unclear what other species it was most closely related to, but it has been classified as a member of the tribe Psittaculini, along with other Mascarene parrots. It had similarities with the Rodrigues parrot
(Necropsittacus rodricanus), and may have been closely related.

The broad-billed parrot's head was large in proportion to its body, and there was a distinct crest of feathers on the front of the head. The bird had a very large beak, comparable in size to that of the

flightless. The bird became extinct in the 17th century owing to a combination of deforestation, predation by introduced invasive species
, and probably hunting as well.

Taxonomy

Dutch activities on Mauritius. A broad-billed parrot is perched on a tree
Woodcut from 1601, with the first published depiction of a broad-billed parrot (5, perched in a tree above).

The earliest known descriptions of the broad-billed parrot were provided by Dutch travellers during the

Rudolf II (Roelant painted other extinct Mauritian species in the emperor's menagerie).[4]

The British naturalist

oceanic islands.[5]

The first known physical remain of the broad-billed parrot was a subfossil mandible collected along with the first batch of dodo bones found in the

metatarsus, and a lower jaw larger than the one that was originally described.[11]

subfossil holotype
mandible, 1866

In 1967, the American ornithologist

Julian Hume reclassified it as a species in the genus Psittacula and called it Thirioux's grey parrot. Hume also reidentified a skull found by Thirioux that was originally assigned to the Rodrigues parrot (Necropsittacus rodricanus) as belonging to the broad-billed parrot instead, making it only the second skull known of this species.[5]

Evolution

The taxonomic affinities of the broad-billed parrot are undetermined. Considering its large jaws and other

osteological features, Newton and Gadow thought it to be closely related to the Rodrigues parrot in 1893, but were unable to determine whether they both belonged in the same genus, since a crest was only known from the latter.[11] The British ornithologist Graham S. Cowles instead found their skulls too dissimilar for them to be close relatives in 1987.[14]

Many endemic Mascarene birds, including the dodo, are derived from South Asian ancestors, and the British ecologist

hotspot islands before the Mascarenes emerged from the sea.[15]

Description

Life restoration by Julian P. Hume
, with colouration based on contemporary accounts

The broad-billed parrot had a disproportionately large head and jaws, and the skull was flattened from top to bottom, unlike in other Mascarene parrots. Ridges on the skull indicate that its distinct frontal

secondary feathers, and a slightly bifurcated tail, with the two central feathers longer than the rest.[16][5] Measurements of some of the first known bones show that the mandible was 65–78 millimetres (2.6–3.1 in) in length, 65 mm (2.6 in) in width, the femur was 58–63 mm (2.3–2.5 in) in length, the tibia was 88–99 mm (3.5–3.9 in), and the metatarsus 35 mm (1.4 in).[11] The sternum was relatively reduced.[5]

Subfossils show that the males were larger, measuring 55–65 centimetres (22–26 in) to the females' 45–55 cm (18–22 in). The sexual dimorphism in size between male and female skulls is the largest among parrots.[5] Differences in the bones of the rest of the body and limbs are less pronounced; nevertheless, it had greater sexual dimorphism in overall size than any living parrot. The size differences between the two birds in the 1601 sketch may be due to this feature.[17] A 1602 account by the Dutch sailor Reyer Cornelisz has traditionally been interpreted as the only contemporary mention of size differences among broad-billed parrots, listing "large and small Indian crows" among the animals of the island. A full transcript of the original text was only published in 2003, and showed that a comma had been incorrectly placed in the English translation; "large and small" instead referred to "field-hens", possibly the red rail and the smaller Cheke's wood rail.[18]

Possible colouration

Henrik Grönvold
(based on the Gelderland sketch), inaccurately showing the bird as entirely blue; the body probably had a different colour in reality

There has been some confusion over the colouration of the broad-billed parrot.[19] The report of van Neck's 1598 voyage, published in 1601, contained the first illustration of the parrot, with a caption stating that the bird had "two or three colours".[3] The last account of the bird, and the only mention of specific colours, was by the German preacher Johann Christian Hoffman in 1673–75:

There are also geese, flamingos, three species of pigeon of varied colours, mottled and green perroquets, red crows with recurved beaks and with blue heads, which fly with difficulty and have received from the Dutch the name of Indian crow.[3]

In spite of the mention of several colours, authors such as the British naturalist

Extinct Birds.[20] Examination of the journal by Hume in 2003 revealed only a description of the dodo. He suggested that the distinctively drawn facial mask may represent a separate colour.[16] Hume suggested in 1987 that in addition to size dimorphism, the sexes may have had different colours, which would explain some of the discrepancies in the old descriptions.[21] The head was evidently blue, and in 2007, Hume suggested the beak may have been red, and the rest of the plumage greyish or blackish, which also occurs in other members of Psittaculini.[5]

In 2015, a translation of the 1660s report of the Dutch soldier Johannes Pretorius about his stay on Mauritius (from 1666 to 1669) was published, wherein he described the bird as "very beautifully coloured". Hume accordingly reinterpreted Hoffman's account, and suggested the bird may have been brightly coloured with a red body, blue head, and red beak; the bird was illustrated as such in the paper. Possible

Joseph M. Forshaw agreed in 2017 that the bill was red (at least in males), but interpreted Hoffman's account as suggesting a more subdued reddish-brown colouration in general, with a pale bluish-grey head, similar to the Mascarene parrot.[23]

Behaviour and ecology

Drawing of two broad-billed parrots
Illustration based on a tracing of the Gelderland sketch, 1896

Pretorius kept various now-extinct Mauritian birds in captivity, and described the behaviour of the broad-billed parrot as follows:

The Indian ravens are very beautifully coloured. They cannot fly and are not often found. This kind is a very bad tempered bird. When captive it refuses to eat. It would prefer to die rather than to live in captivity.[22]

Though the broad-billed parrot may have fed on the ground and been a weak flier, its

Norfolk Island kaka.[22]

Subfossil broad-billed parrot bones
Subfossil leg bones, a mandible, and a sternum, 1893

Sexual dimorphism in beak size may have affected behaviour. Such dimorphism is common in other parrots, for example in the

New Zealand kaka. In species where it occurs, the sexes prefer food of different sizes, the males use their beaks in rituals, or the sexes have specialised roles in nesting and rearing. Similarly, the large difference between male and female head size may have been reflected in the ecology of each sex, though it is impossible to determine how.[5][24]

In 1953, the Japanese ornithologist

leeward side of Mauritius, which was the most accessible for people, and it was noted that birds were more abundant near the coast, which may indicate that the fauna of such areas was more diverse. It may have nested in tree cavities or rocks, like the Cuban amazon. The terms raven or crow may have been suggested by the bird's harsh call, its behavioural traits, or just its dark plumage.[5]
The following description by the Dutch bookkeeper Jacob Granaet from 1666 mentions some of the broad-billed parrot's co-inhabitants of the forests, and might indicate its demeanour:

Sir Thomas Herbert from 1634 showing a broad-billed parrot ("Cacato"), a red rail, and a dodo

Within the forest dwell parrots, turtle and other wild doves, mischievous and unusually large ravens [broad-billed parrots], falcons, bats and other birds whose name I do not know, never having seen before.[3]

Many other endemic species of Mauritius were lost after human colonisation, so the

palm orchid, have also become extinct.[27]

Diet

Brown seeds
Seeds of Latania loddigesii, perhaps part of this parrot's diet

Species that are morphologically similar to the broad-billed parrot, such as the

Diospyros egrettorium, and Pandanus utilis.[5] The broad-billed parrot and other extinct Mascarene birds, such as the dodo and the Rodrigues solitaire could only reach seeds at low heights, and were therefore probably important seed-dispeersers, able to destroy the largest seeds among the Mascarene flora.[28]

On the basis of

Psephotus, actually have weak jaws in life, and that the morphologies cited by Holyoak do not indicate strength.[31] Hume pointed out in 2007 that the mandible morphology of the broad-billed parrot is comparable to that of the largest living parrot, the hyacinth macaw, which cracks open palm nuts with ease. It is therefore probable that the broad-billed parrot fed in the same manner.[32]

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

The Brazilian ornithologist Carlos Yamashita suggested in 1997 that macaws once depended on now-extinct South American megafauna to eat fruits and excrete the seeds, and that they later relied on domesticated cattle to do this. Similarly, in Australasia the palm cockatoo feeds on undigested seeds from cassowary droppings.[5][33] Yamashita also suggested that the abundant Cylindraspis tortoises and dodos performed the same function on Mauritius, and that the broad-billed parrot, with its macaw-like beak, depended on them to obtain cleaned seeds.[34]

Extinction

Though Mauritius had previously been visited by

Maurice of Nassau, and it was used from then on for the provisioning of trade vessels of the Dutch East India Company.[36] To the Dutch sailors who visited Mauritius from 1598 and onwards, the fauna was mainly interesting from a culinary standpoint.[19] Of the eight or so parrot species endemic to the Mascarenes, only the echo parakeet of Mauritius has survived. The others were likely all made extinct by a combination of excessive hunting and deforestation.[5]

Because of its poor flying ability, large size and possible island tameness, Hume stated in 2007 the broad-billed parrot was easy prey for sailors who visited Mauritius, and their nests would have been extremely vulnerable to predation by introduced crab-eating macaques and rats. Various sources indicate the bird was aggressive, which may explain why it held out so long against introduced animals after all. The bird is believed to have become extinct by the 1680s, when the palms it may have sustained itself on were harvested on a large scale. Unlike other parrot species, which were often taken as pets by sailors, there are no records of broad-billed parrots being transported from Mauritius either live or dead, perhaps because of the stigma associated with ravens.[5][22] The birds would not in any case have survived such a journey if they refused to eat anything but seeds.[34] Cheke pointed out in 2013 that hunting of this species was never reported and that deforestation was minimal at the time. He also suggested that old birds would have survived long after reproduction was possible.[37]

References

  1. doi:10.2305/IUCN.UK.2016-3.RLTS.T22728847A94998733.en
    . Retrieved 12 November 2021.
  2. ^ a b c d Cheke & Hume 2008, pp. 23–25.
  3. ^ a b c d Cheke & Hume 2008, p. 172.
  4. S2CID 226613585
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  5. ^ a b c d e f g h i j k l m n o p q r s t Hume 2007, pp. 4–17.
  6. ISBN 978-1-4081-5725-1
    .
  7. doi:10.1111/j.1474-919X.1866.tb06084.x
    .
  8. ^ Owen, R. (1869). "On the osteology of the dodo (Didus ineptus Linń.)". Transactions of the Zoological Society. 6: 49–86.
  9. doi:10.1111/j.1474-919X.1876.tb06925.x
    .
  10. ISBN 978-1-4081-2501-4. Archived from the original
    on 29 October 2013.
  11. ^
    doi:10.1111/j.1469-7998.1893.tb00001.x
    .
  12. ISBN 978-0-486-21869-4
    .
  13. doi:10.1111/j.1474-919X.1973.tb01980.x
    .
  14. ISBN 978-0-511-73576-9.{{cite book}}: CS1 maint: location missing publisher (link
    )
  15. ^ a b Cheke & Hume 2008, p. 71.
  16. ^
    doi:10.3366/anh.2003.30.1.13
    .
  17. doi:10.11646/zootaxa.1513.1.1
    . p. 51.
  18. ^ Cheke, A. S. (2013). "A single comma in a manuscript alters Mauritius avian history" (PDF). Phelsuma. 21: 1–3.
  19. ^
    ISBN 978-0-8014-3954-4
    .
  20. ^ Rothschild, W. (1907). Extinct Birds. London: Hutchinson & Co. p. 49.
  21. ISBN 978-0-521-11331-1
    .
  22. ^
    S2CID 84473440
    .
  23. ISBN 9780643096325
    .
  24. ISBN 978-0-691-09251-5
    .
  25. doi:10.1017/S0030605300020457
    .
  26. doi:10.1017/S0030605300012643
    .
  27. ISBN 978-0-7136-6544-4
    . pp. 371-373.
  28. S2CID 225292938
    .
  29. ^ Holyoak, D. T. (1971). "Comments on the extinct parrot Lophopsittacus mauritianus". Ardea. 59: 50–51.
  30. doi:10.1071/MU973157
    .
  31. doi:10.1111/j.1474-919X.1975.tb04187.x
    .
  32. ^ Hume, J. P.; R. P. Prys-Jones, R. P. (2005). "New discoveries from old sources, with reference to the original bird and mammal fauna of the Mascarene Islands, Indian Ocean" (PDF). Zoologische Mededelingen. 79 (3): 85–95.
  33. ^ Yamashita, C. (1997). "Anodorhynchus Macaws as a followers of extinct megafauna: an hypothesis". Ararajuba. 5 (2): 176–182.
  34. ^ a b Cheke & Hume 2008, p. 38.
  35. ISBN 978-0-00-714572-0
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  36. S2CID 128421372
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  37. ^ Cheke, A. S. (2013). "Extinct birds of the Mascarenes and Seychelles – a review of the causes of extinction in the light of an important new publication on extinct birds". Phelsuma. 21: 4–19.

External links

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