Eclectus

The parrot genus Eclectus consists of two known species, the extant eclectus parrot (Eclectus roratus) and the extinct oceanic eclectus parrot (Eclectus infectus). The extant eclectus parrot (Eclectus roratus) is a medium sized parrot native to Oceania, particularly New Guinea and Australia. Males are mostly bright green, while females are a bright red. The male and female eclectus look so different from each other that they were thought to be different species for many years. Conservationally, they are of least concern.[1] Eclectus parrots do well in captivity, and are a very popular pet across the world.

Eclectus
A pair of eclectus parrots (Eclectus roratus)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Family: Psittaculidae
Tribe: Psittaculini
Genus: Eclectus
Wagler, 1832

Description

Eclectus parrots generally have a big head and a short tail, and are striking in their coloration. They measure about 35–42 cm in length.[1] They unusually exhibit reverse sexual dichromatism, a form of sexual dimorphism where the two sexes have differential coloration.  Males are mostly green, with bright red underwings, blue primaries, and a yellow beak, while females are a striking red with a royal blue underbelly and black beak.[2]

Usually when birds exhibit sexual dimorphism, it comes with a sex role reversal, in which the males who usually gather food are left to incubate eggs, while the female forages. It is important to note that in the eclectus, no such sex role reversal occurs. The male still forages, while the female incubates the eggs. Research has shown this dimorphism with no role reversal is a product of the rare nest hollows, and the selective pressures that accompany this.[3][4]

It is thought that sexual selection has affected these birds in this way in order to provide camouflage for the male, while making the female a beacon, which is not what is usually seen in sexually dimorphic birds.[3] Good nesting sites are rare to come by, so the female’s bright coloration alerts other males to females with hollows in the area, with whom they can then mate. It also serves as a signal to other females that the nesting site is occupied. The male is primarily responsible for obtaining food for the female and chicks, so his green coloration provides adequate camouflage from predators, such as peregrine falcons, while he is in the rainforest canopy in search of food. The male also has UV coloration in his feathers, which allows him to appear extra radiant to females, who are able to visualize the UV spectrum, yet remain camoflauged to predators who cannot. This unique coloration is evidence of an evolutionary compromise between the need to attract and compete for mates, and the risk of predation.[3][4]

Taxonomy

Eclectus parrots are of the class Aves, order Psittaciformes, family Psittacidae, and genus Eclectus. The extinct oceanic eclectus parrot was of species Eclectus infectus, while the extant ecectus parrot is of species Eclectus roratus.[5] The oceanic eclectus parrot is thought to be from the late Pleistocene to the Holocene epoch, and was found in Vanuatu, Fiji, and on the Tonga Archipelago. It became extinct around 3000 years ago as a result of human settlement in these areas during that time.[1] The genus was named by Johann Georg Wagler in 1832. The epithet derives from eklektos, the ancient Greek cum Latin term for 'chosen one'; Wagler acknowledges the Latin in a publication later the same year.[6]

There are 9 subspecies of the extant eclectus roratus including the following:[5]

  1. Eclectus roratus aruensis: Aru Island eclectus parrot
  2. Eclectus roratus biaki: Biak Island eclectus parrot
  3. Eclectus roratus cornelia: Sumba Island eclectus parrot
  4. Eclectus roratus macgillivrayi: Australian eclectus parrot
  5. Eclectus roratus polychloros: New Guinea Red-sided eclectus parrot
  6. Eclectus roratus riedeli: Tanimbar Island eclectus parrot
  7. Eclectus roratus roratus: grand eclectus parrot
  8. Eclectus roratus solomonenisis: Solomon Islands eclectus parrot
  9. Eclectus roratus vosmaeri: Vosmaer’s eclectus parrot

Females of the Red-sided, Solomon Island, Australian, Aru Island, and Biaki eclectus all display a blue eye ring, blue breast, and do not have yellow in their plumage. The grand eclectus and Vosmaer’s eclectus both lack the blue eye ring, and have a purple breast. Both the Tanimbar Island and Sumba Island eclectus are completely red, but the Sumba Island eclectus is larger than the Tanimbar, while the Tanimbar has yellow on its tail. The Australian eclectus is the largest of all the subspecies, at 37 cm.[7]

In 2019, Birdlife International proposed that the eclectus parrot be split into four species,[8] which are also recognized by the IUCN Red List.[9]

  • Moluccan Eclectus (Eclectus roratus) - including subspecies voesmaeri
  • Papuan Eclectus (Eclectus polychloros) - including subspecies aruensis, biaki, macgillivrayi, and solomonensis
  • Sumba Eclectus (Eclectus cornelia)
  • Tanimbar Eclectus (Eclectus riedeli)

Habitat and Distribution

The eclectus parrot is endemic to rainforests from New Guinea to the Solomon Islands, and the tip of the Cape York Peninsula of Australia. On the peninsula, they are restricted to rainforest patches in the Iron and McIllwraith ranges.[2] Though geographically, the areas of Papua New Guinea and Australia where these parrots live seem relatively close together, these parrots do not fly enough to be able to cross the 70 miles between the peninsula and mainland Papua New Guinea. As such, it is thought that they expanded from Papua New Guinea into Australia around 10,000 years ago, when the two were connected by a land bridge. They prefer to stay in the canopy level of the rainforests, and can nest anywhere from 20 to 30 meters above the ground. Breeding hollows lower than this height tend to flood easily in the rainforest climate, and are generally avoided if possible.[2][10]

Behavior

Vocalizations

Eclectus parrots have a varied range of calls, from a loud, high-pitched squawk to whistles and screeches.[1] They have also been observed to make a chime-like call when a male returns to the nest with food, in what seems to be a show of gratitude or an acknowledgement of return.[11]

Diet

In the wild, eclectus parrots primarily feed on various fruits and their pulp. However, they will also feed on seeds, leaf buds, blossoms, nectar, figs, and nuts. They are frequently found to be eating the pulp of the fruit of Salacia chinensis (lolly berry) and Leea indica (bandicoot berry), and the seeds of Dodonea lanceolata. These items are of high nutritional value to the birds.[11]

These parrots eat intermittently, in order to increase food storage capacity and process means as quick and efficiently as possible. They have special adaptations in their digestive system to help them with this. Their esophagus is wide and flexible, to allow the fast passage of food and rapid digestion, and their proventriculus (glandular region between the crop and gizzard) is elongated and highly distensible, allowing it to hold comparable amounts of food as the crop. Ecelctus parrots can produce the fat they don’t get from their diet endogenously in their liver, from hexose sugars found in the fruit pulp they eat.[11]

After securing a good nesting hollow, females generally never leave the nest unless threatened, so the males are primarily responsible for feeding the female and her chicks. They have been observed to travel long distances in search of food, some over a 30 km2 range. The males usually feed the female in the mornings and the afternoons, and generally stick to a strict and regulated feeding schedule.[11]

Reproduction

As stated previously, eclectus parrots nest in hollow cavities 20 to 30 meters above the ground. Optimal nesting hollows are relatively rare within the eclectus’ habitat, and can be very difficult to find.[10] As such, females tend to monopolize good nesting hollows once found, staying there up to 11 months a year, and returning to the same nest at times for multiple years. Females have been known to fight off other females, sometimes to the death, to defend their nesting hollows. Males have been known to travel unusually large distances to mate with females, the longest found being 7.2 kilometers (4.5 miles).[2]

Eclectus parrots are unusual among parrots because they exhibit both polyandrous mating (females mate with multiple males) and polygynandrous mating (males mate with multiple females and females mate with multiple males).[2] Even more unusual, these birds exhibit a form of polyandry known as cooperative polyandry,[12] in which multiple males breed with a single female, and all the males work together to help the female raise the chicks, rather than compete with each other. They are the only parrot known to do this. Females will lay 2 eggs per clutch, but often only fledge 1 young.[13]

Eclectus are also unusual in that they can bias the sex of their offspring, such that they can manipulate whether their offspring are male or female.[13] It is thought that this behavior occurs as a result of the scarcity of their nesting hollows.[10][2] As such, females will only have male offspring when resources are plentiful, a good nesting hollow is secured, and many males are around to feed her and her offspring, as male offspring are more energetically expensive to raise as compared to females.[2]

References
  1. Collar, Nigel; Kirwan, Guy M.; Boesman, Peter F. D. (2020-03-04), Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.), "Eclectus Parrot (Eclectus roratus)", Birds of the World, Cornell Lab of Ornithology, doi:10.2173/bow.eclpar.01, retrieved 2020-10-13
  2. Heinsohn, Robert (June 2008). "Ecology and Evolution of the Enigmatic Eclectus Parrot (Eclectus Roratus)". Journal of Avian Medicine and Surgery. 22 (2): 146–150. doi:10.1647/2007-031.1. ISSN 1082-6742.
  3. Heinsohn, Robert; Legge, Sarah; Endler, John A. (2005-07-22). "Extreme Reversed Sexual Dichromatism in a Bird Without Sex Role Reversal". Science. 309 (5734): 617–619. doi:10.1126/science.1112774. hdl:10536/DRO/DU:30023060. ISSN 0036-8075. PMID 16040708.
  4. Heinsohn, Robert (2008-07-01). "The ecological basis of unusual sex roles in reverse-dichromatic eclectus parrots". Animal Behaviour. 76 (1): 97–103. doi:10.1016/j.anbehav.2008.01.013. ISSN 0003-3472.
  5. Integrated Taxonomic Information System. "Eclectus roratus". ITIS.
  6. Gray, Jeannie; Fraser, Ian (2013). Australian Bird Names: A Complete Guide. Collingwood, Victoria: Csiro Publishing. p. 143. ISBN 978-0-643-10471-6.
  7. "Eclectus Parrots - Sub-species Identification | Beauty of Birds". www.beautyofbirds.com. Retrieved 2020-10-13.
  8. https://globally-threatened-bird-forums.birdlife.org/eclectus-parrot-eclectus-roratus-is-being-split-assessment-of-newly-recognised-taxa/
  9. "Sumba Eclectus". IUCN Red List. IUCN. Retrieved 31 December 2020.
  10. Legge, S.; Heinsohn, R.; Garnett, S. (2004). "Availability of nest hollows and breeding population size of eclectus parrots, Eclectus roratus, on Cape York Peninsula, Australia". Wildlife Research. 31 (2): 149–161. doi:10.1071/wr03020. ISSN 1448-5494.
  11. "Exploring The Wild Diet". birdhealth. Retrieved 2020-10-13.
  12. Heinsohn, Robert; Ebert, Daniel; Legge, Sarah; Peakall, Rod (2007-10-01). "Genetic evidence for cooperative polyandry in reverse dichromatic Eclectus parrots". Animal Behaviour. 74 (4): 1047–1054. doi:10.1016/j.anbehav.2007.01.026. ISSN 0003-3472.
  13. Heinsohn, Robert; Legge, Sarah; Barry, Simon (1997). "Extreme Bias in Sex Allocation in Eclectus Parrots". Proceedings: Biological Sciences. 264 (1386): 1325–1329. ISSN 0962-8452.
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