Echo parakeet
Echo parakeet | |
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Female by a feeding hopper
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Psittaciformes |
Family: | Psittaculidae |
Genus: | Psittacula |
Species: | P. eques
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Binomial name | |
Psittacula eques (Boddaert, 1783)
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Subspecies | |
Current range (red) in Mauritius | |
Synonyms | |
The echo parakeet (Psittacula eques) is a
The echo parakeet is 34–42 cm (13–17 in) long, weighs 167–193 g (5.9–6.8 oz), and its wingspan is 49–54 cm (19–21 in). It is generally green (the female is darker overall) and has two collars on the neck; the male has one black and one pink collar, and the female has one green and one indistinct black collar. The upper bill of the male is red and the lower blackish brown; the female's upper bill is black. The skin around the eyes is orange and the feet are grey. Juveniles have a red-orange bill, which turns black after they fledge, and immature birds are similar to the female. The Réunion parakeet had a complete pink collar around the neck, whereas it tapers out at the back in the Mauritius subspecies. The related rose-ringed parakeet which has been introduced to Mauritius is similar, though slightly different in colouration and smaller. The echo parakeet has a wide range of vocalisations, the most common sounding like "chaa-chaa, chaa-chaa".
As the species is limited to forests with native vegetation, it is largely restricted to the
Taxonomy
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
The green parakeets of Mauritius and Réunion were usually treated together in historical literature, and their histories have consequently been muddled.
In a 1987 book about Mascarene birds, the British ecologist
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.[12][13] The local Mauritian name is cateau vert, kato, or katover (derived from French).[11][7] 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.[4][12]
Evolution
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.[14]
In 2007, based on
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.[16]
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
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In 2018, the American ornithologist Kaiya L. Provost and colleagues found the
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
Also in 2017, Australian ornithologist
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
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
Description
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
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.[12] 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.[13][14][27]
Vocalisations
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.[11][28][13]
Habitat and distribution
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
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.[29]
Behaviour and ecology
The echo parakeet is
The activity patterns of the echo parakeet are similar to those of other Psittacula parakeets in most respects. They mainly
Breeding
The breeding behaviour of the echo parakeet is similar to that of other Psittacula parakeets, most of which can breed by the time they are two years old.
Pair maintenance behaviour is demonstrated throughout the year, the male usually being assertive, and includes
Eggs are laid between August and October, mostly in late September and early October, and late
Two of the young are normally raised.[13] Chicks develop slowly, with dark feather tracts visible on the back and primary quills after five days. The tracts are more visible after ten days when down tips breakthrough, their eyes are slit-like as they begin to open, and the legs turn from pinkish to pale grey. The eyes are almost fully open after fifteen days, and the chicks have a fine covering of greenish-grey down on most of the body, the secondary quills emerge, and feather tracts appear on the crown of the head. They are completely covered by greenish down after twenty days, and after thirty days the wing and tail feathers emerge. After forty days, all contour, wing, and tail feathers are well developed, but down is still retained on the lower parts and flanks. When nestlings are developed enough, they can threaten nest intruders with loud growls and bites but will retreat into nooks and stay still if the intruder persists. After fifty days, the chicks are rather active, flapping their wings and venturing near the entrance hole. Chicks fledge after 50–60 days, between late October and February, and fledglings remain near the nest entrance sometime after leaving. They accompany their parents to forage as soon as they can fly, and remain with them and are fed for two to three months after leaving the nest. The young have been observed imitating adults which were carefully selecting fruits, and have been observed being fed by adults as late as March.[23][11]
Additional adult male echo parakeets acting as "helpers" by feeding the nesting female and the nestlings (usually rebuffed by the nesting pair, but sometimes disrupting nesting by making the pair leave their nest) were speculated to be correlated with a skewed sex ratio in the 1980s. The "helpers" were thought to be perhaps a recent phenomenon, possibly due to the destruction of foraging areas, and many non-breeding birds consequently being displaced to other areas, creating an unsustainable excess in the populations there.[11] In the late 1990s, it was reported that the echo parakeet is perhaps not monogamous, but has a tendency for polyandry, where breeding groups consist of multiple males and a single female (though monogamous pairs were also observed). It was also shown that the sex ratio in the population is consistently biased towards males according to historical counts. A 2008 genetic study by the British biologists Tiawanna D. Taylor and David T. Parkin showed that the sex ratio was equal among echo parakeet chicks and embryos and that the male-biased sex ratio among adults is therefore not due to, for example, inbreeding.[31] A preliminary 2009 genetic study by Taylor and Parkin showed that matings of "auxiliary males" with the female of a breeding pair do occur, and that the echo parakeet is therefore not strictly monogamous. Such a mating system is beneficial to the conservation of the species, as it increases genetic diversity, but it is unclear why such breeding groups form.[32]
Diet and feeding
The echo parakeet mainly feeds on native Mauritian plants, though small amounts of
Echo parakeets never forage on the ground, in contrast to the rose-ringed parakeet, and may have been pushed into an arboreal niche because other parrots of Mauritius were already adapted for ground feeding.
The echo parakeet forages in different areas in different seasons, and dwarf forest and scrubland are important throughout the year, the birds feeding on different species as edible parts become available. However, the fruiting of many plants is irregular and some species have become rare, and food is therefore not always seasonally available. When fruits are scarce during winter and early spring, the birds eat more leaves and spend more time foraging. The birds wander in search for food, sometimes several kilometres to and from an area. The echo parakeet forages alone or in small groups with individuals ignoring each other, but since so few birds used to exist, it has been hard to estimate how social the species is. Pairs stay loosely associated throughout the year and forage together. They mainly forage during the morning and late afternoon, feeding activity diminishing during harsh weather.[11]
Echo parakeets are silent when they clamber around feeding. They remove fruits and flowers with their bills, sometimes hanging upside down to reach, the food is then held by a foot while eaten. When feeding on Tabernaemontana mauritiana leaves, the parakeets often scoop out the
Aggression and competition
Psittacula parakeets employ
The echo parakeet is only territorial during the
The rose-ringed parakeet (of the subspecies P. k. borealis[14]) was introduced to Mauritius around 1886 and is now flourishing there. Its population is estimated at 10,000 birds and it is widespread across Mauritius. Closely related to the echo parakeet and physically similar, though no hybrids have been recorded, they compete for nest-sites and probably some food. The two species are usually passive towards each other outside the breeding season; they have been seen pursuing each other as well as flying together and feeding in the same trees. While the rose-ringed parakeet has much broader feeding requirements (and may be ecologically separated), it may have excluded the echo parakeet from expanding and adjusting its feeding ecology to the changing environment by entirely occupying this more generalised niche. The most serious form of competition between the echo parakeet and the rose-ringed parakeet is over nest-sites; the introduced species often takes over cavities used by the native parakeets. Echo parakeets are reportedly easily frustrated when defending their nest-territories and have been seen relinquishing them without physically defending them. Two out of seven echo parakeet nest cavities were taken over by rose-ringed parakeets in 1974, and only rose-ringed parakeets were nesting in the Macabé Ridge area for several years.[11][27][33]
Status
Decline
There are believed to have been seven endemic Mascarene parrot species; all but the echo parakeet have vanished. The others were likely made extinct by a combination of excessive hunting and deforestation by humans, as well as the invasive species brought with them (through predation and competition). On Mauritius, the echo parakeet coexisted with the broad-billed parrot (Lophopsittacus mauritianus) and the Mascarene grey parakeet (Psittacula bensoni), and the Réunion parakeet lived alongside the Mascarene parrot and the Mascarene grey parakeet. Newton's parakeet and the Rodrigues parrot (Necropsittacus rodricanus) lived on nearby Rodrigues. Worldwide, many parrots have been driven to extinction by humans; island populations have been especially vulnerable, partially due to their tameness. To the sailors who visited the Mascarene Islands from the late 16th-century onwards, the fauna was largely viewed as a source of food.[4][5] Many other endemic species of Mauritius were lost after the arrival of humans to the island, including the dodo (Raphus cucullatus, which has since become a symbol of extinction), so the ecosystem of the island is severely damaged and hard to reconstruct. The surviving endemic fauna is still seriously threatened. Before humans arrived, Mauritius was entirely covered in forests, almost all of which have since been lost.[34]
The last report of the Réunion parakeet is that of the French colonist Joseph-François Charpentier de Cossigny from 1732, and Hume expressed surprise that the population disappeared so quickly after the arrival of humans, considering the available habitat and the fact that the Mauritius population managed to survive. Hume estimated that the Réunion parakeet had gone extinct due to hunting and deforestation around 1730–50.[4] Jones and colleagues pointed out that other Mascarene birds survived into the 18th and 19th centuries without being noted, and suggested that the Réunion parakeet could have survived as late as the early 19th century (Jossigny's sketch could support the parakeet surviving at least until c. 1770).[12] Cossigny's final 1732 account of the Réunion parakeet (and the last of the Mascarene grey parakeet) reads as follows:
The woods are full of parrots, either completely grey or completely green. They were eaten a lot formerly, the grey especially, but both are always lean and very tough whatever sauce one puts on them.[4]
The Dutch soldier Johannes Pretorius (on Mauritius from 1666 to 1669) reported that there were many parrots, and that echo parakeets were caught alive with nets, but could sometimes not be caught, being too high up in trees. Parrots were often caught to be given as gifts or sold during the 17th century and were probably kept alive on Mauritius before being exported. That the parrots kept to high trees indicates they had become wary of humans at this time.[35] In 1754 and 1756, D. de La Motte described the abundance of echo parakeets in Mauritius, and their use as food:
One eats here [in Mauritius] a good number of long-tailed green parrots called perruches whose flesh is black and very good. A hunter can kill three or four dozen in a day. There is a time of year when these birds eat a seed that makes their flesh bitter and even dangerous.[4]
Assessments of the echo parakeet's status varied in early literature; while it was said to be "quite common" in the 1830s, by 1876 the Newtons said "its numbers are gradually falling". In 1904, the French naturalist Paul Carié said the population was "reasonably large", while Rothschild said the bird was rare and apparently "on the verge of extinction" in 1907. Areas where the echo parakeet could be found were cleared for tea and forestry from the 1950s to the 1970s, and the birds were forced into the remaining native habitat, in and around the Black River Gorges. 50 pairs were estimated to be left in 1970, though this may have been too high. By 1975, it was estimated that about 50 individuals remained, but the population appears to have dropped noticeably in the following years, and by 1983 only a flock of 11 birds was seen, which was believed to represent the entire population. The drop in numbers around this time may have been tied to cyclone Claudette in December 1979. There was little nesting success, and the parakeets reproduced at a level below that necessary for replacement.[11]
Conservation
The plight of the endangered Mauritian birds attracted the attention of ornithologists beginning in the early 1970s, who went to the island to study them. The Mauritius kestrel was by 1973 considered the rarest bird in the world, with only six individuals left, and the pink pigeon numbered about 20 birds in the wild; both species were later saved from extinction through captive breeding by the
In 1980, Carl Jones described the situation as desperate, and stated that the remaining birds would have to be caught for captive breeding if the echo parakeet was to be saved; this solution was also recommended by the
In 1996, six previously unknown echo parakeet breeding groups were found in the Black River Gorges, some in areas of the Bel Ombre forest that had not been surveyed before and others within the known breeding range. These almost doubled the number of breeding groups from those seen the previous season. The echo parakeet was made a priority project by the Mauritian Wildlife Foundation following the season's breeding success, and it was decided to initiate a captive breeding programme at the Gerald Durrell Endemic Wildlife Sanctuary.[39] It was discovered that from clutches of three or four eggs, only one chick would usually fledge, so the team began to take the surplus; the parents could more easily raise the brood they were left with, and such surplus chicks would be given to pairs that had failed to hatch their eggs. Many surplus chicks were also taken to the breeding centre where they were reared successfully, and the first three birds bred in captivity were released into the wild in 1997. These and later hand-reared birds were found to be too tame and naive; they would land on people's shoulders, or near cats and mongooses, which subsequently killed them. Jones decided to release the captive-bred birds after nine to ten weeks when fledging would normally occur, instead of seventeen, and these young birds were better at integrating with wild birds, and learning social and survival skills. Captive-bred birds who had learned to use feeding hoppers in captivity passed on this ability to wild birds, and the number of birds that fed at food hoppers and used nest boxes provided by the team increased in the following years. The birds had not used the nest boxes before 2001, after which they were improved in design.[36][40] By 1998, there were 59–73 birds, including 14 that had been captive bred since 1997.[37]
By 2005, 139 captive birds had been released and intensive management of the wild population ceased in 2006. Since then only supplemental food and nest boxes have been provided. By 2007, about 320 echo parakeets lived in the wild, with numbers growing, and the species was downgraded from
Threats
The main threat to the species is destruction and alteration of its native habitat, resulting in the loss of feeding areas, which would force the birds to travel widely to find food. In times of food shortage, the female may not receive adequate amounts of food from the male and would be forced to leave the nest to forage, sometimes abandoning it completely. Parakeets have difficulties finding new nest sites if their nests are destroyed or taken by competitors, and many of the old trees used for nesting sites have been destroyed by cyclones; cyclones also kill birds and remove the fruit from trees. Competitors for nest-cavities include bees and wasps, white-tailed tropic-birds, rose-ringed parakeets,
An isolated case of psittacine beak and feather disease was recorded in an echo parakeet in 1996; in 2004 there was a significant outbreak, and a subsequent screening programme showed that more than 30% of sampled birds had encountered the disease. Birds younger than two years old are most affected, and 40–50% of fledglings die from it and associated infections each year. Some birds recover, but it is not known if they remain carriers of the disease and pass it on to their offspring, or how it is spread.[23] The disease is also found in local rose-ringed parakeets, but it is not known in which direction it was first transmitted.[33] Though Temple speculated that the population crash in the 1970s was due to disease, no evidence supports this. No parasites were found in droppings examined in the 1970s.[11]
References
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- ^ "Black River Gorges National Parks". npcs.govmu.org. National Parks and Conservation Service. Archived from the original on 27 July 2018. Retrieved 11 February 2019.
- ^ "More wild Echo Parakeets found". Issuu (8): 9. 1996.
- ^ Tatayah, R. V. V.; Malham, J.; Haverson, P.; Van de Wetering, J. (2007). "Design and provision of nest boxes for echo parakeets Psittacula eques in Black River Gorges National Park, Mauritius". Conservation Evidence. 4: 16–19. Archived from the original on 2019-02-17. Retrieved 2019-02-17.
- ^ Harvey, F. (2019). "Flightless bird provides 'spark of hope' amid environmental crisis". The Guardian. Retrieved 10 December 2019.
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- ^ Tatayah, R. V. V.; Malham, J.; Haverson, P. (2007). "The use of copper strips to exclude African giant land-snails Achatina spp. from echo parakeet Psittacula eques nest cavities, Black River Gorges National Park, Mauritius". Conservation Evidence. 4: 6–8. Archived from the original on 2019-02-17. Retrieved 2019-02-17.
External links
- Professor Carl Jones: The Story of the Echo Parakeet – video by Durrell Wildlife Conservation Trust