Meratus white-eye

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Meratus white-eye
Zosterops meratusensis 241289656.jpg
Holotype male
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Zosteropidae
Genus: Zosterops
Species:
Z. meratusensis
Binomial name
Zosterops meratusensis
Irham, Haryoko, Shakya, Mitchell, S, Burner, Bocos, Eaton, Rheindt, Suparno, Sheldon & Prawiradilaga, 2021

The Meratus white-eye (Zosterops meratusensis) is a species of bird in the white-eye family, Zosteropidae. The species was described in 2021 by the Indonesian ornithologist Mohammed Irham and his colleagues based on genetic, morphological, and vocal differences from other Zosterops white-eyes. It is endemic to the Meratus Mountains of Indonesian Borneo, where it has been recorded from Mount Besar and Mount Karokangen. It inhabits the mid and lower storeys of closed-canopy montane forests at elevations between 1,300 and 1,650 m (4,270 and 5,410 ft). It is a typical Zosterops white-eye, with deep olive-green upperparts, yellower underparts, a yellow stripe across the lores, and a distinctive bicoloured bill. Adults have a length of around 11–12 cm (4.3–4.7 in) and a mass of 8.5–9.5 g (0.30–0.34 oz). Both sexes look alike.

Contents

Most aspects of the Meratus white-eye's ecology are unknown. It has it has been seen in mixed-species foraging flocks with other insectivores. Its breeding is also poorly studied, but presumed juveniles have been seen in the second week of July. The species is classified as being of least-concern by the International Union for Conservation of Nature (IUCN) on the IUCN Red List. It is thought to be locally common within the small area it inhabits and is not currently threatened, although the songbird trade may represent a future threat. Recommended conservation measures for the species include surveys to accurately estimate its population, finding the demand for the species in the songbird trade, and finding suitable tracts of habitat to protect.

Taxonomy

The Meratus Mountains of southeastern Borneo are a small isolated patch of montane forest, surrounded by heavily degraded lowland habitats and separated from Borneo's main mountain range by a distance of around 300 km (190 mi). These mountains have high levels of endemism, but have been poorly studied ornithologically, with few expeditions having studied the birds of the region. [2] Zosterops white-eyes representing a previously-unknown species were first documented from the mountain range in July 2016; [2] [3] specimens of the species were collected the next year by a expedition of the Bogor Zoology Museum and the Louisiana State University Museum of Natural Science. The Meratus white-eye was probably previously seen during a 1996 expedition by the British ornithologist Geoffrey Davison, although he identified his sightings as black-capped white-eyes. [3]

The species was described in 2021 as Zosterops meratusensis by the Indonesian ornithologist Mohammed Irham and his colleagues on the basis of an adult male specimen collected from Mount Besar in 2017. This description was based on genetic, morphological, and vocal differences from other Zosterops white-eyes. It was described alongside the Meratus blue flycatcher, another species that was first recorded in 2016. [2] The name of the genus, Zosterops, is derived from the Ancient Greek words zōstēr, meaning 'belt' or 'girdle', and ōps, meaning 'eye'. [4] The specific epithet is named after the Meratus Mountains that are the species' type locality. 'Meratus white-eye' is the official common name designated by the International Ornithologists' Union (IOU). [5] In Indonesian, it is called Kacamata Meratus. [2]

The Meratus white-eye is one of over 100 species currently placed in the genus Zosterops, in the white-eye family, Zosteropidae. It has no subspecies. [5] It is most closely related to the lemon-bellied and Wakatobi white-eyes. [6] [7]

Description

The Meratus white-eye is a typical Zosterops white-eye with deep olive-green upperparts, more yellow underparts, a yellow stripe across the lores, and a distinctive bicoloured bill. Adults have a length of around 11–12 cm (4.3–4.7 in) and a mass of 8.5–9.5 g (0.30–0.34 oz). The wing length is 48.7–50.8 mm (1.92–2.00 in), the length of the bill is 35 mm (1.4 in), and the tail length is 12.5–13.7 mm (0.49–0.54 in). The species shows no sexual dimorphism; males and females both look alike. [6]

The eye-ring is white, broken in the front by a narrow black loral line that continues below the eye-ring, and may be widest below the eye. There is a narrow olive-yellow streak above the loral line. The upperparts are mostly uniform yellowish olive-green, with blackish streaks on the top of the head. The flight feathers are dusky brown with yellow to greenish olive edges. The throat is somewhat streaky yellow, turning more olive-yellow on the breast, and the belly is yellow-orange tinted yellow. The flanks and thighs are yellowish olive-green and olive-yellow. The exact amount of yellow on the underside varies between individuals.The uppertail-coverts are between yellowish olive-green to citrine and brighter than the rest of the upperside. The undertail-coverts are sulfur yellow with an orange-yellow that increases towards the tip, while the tail is dusky brown with paler edges. The bill is mostly pinkish-horn, with the upper ridge of the maxilla and the tip of the mandible being a darker greyish-horn. This appears conspicuous in the field, with the pinkish-orange mandible contrasting with its greyish tip and the darker grey maxilla. The iris is dark brown and the feet are grayish-horn or steel-grey, with paler toe pads. Individuals thought to be juveniles have paler, duller bills and may also have thinner eye-rings with a post-ocular gap. [6]

The only other species of white-eye that also occurs in the Meratus Mountains is Hume's white-eye, which is much alike to the Meratus white-eye in terms of structure and dimensions. That species has brighter green upperparts, yellow chin and throat, a yellow stripe down the underparts that contrasts the surrounding soft gray, and a monochromatic bill. Additionally, Hume's white-eye is found at lower elevations than the Meratus white-eye. The three other montane white-eyes found on Borneo, the black-capped white-eye, pygmy white-eye, and mountain blackeye, do not overlap in range with the Meratus white-eye. They can also be easily differentiated from the Meratus white-eye by the latter's uniform yellowish-olive colouration and white eye-ring. [6]

Compared to the Javan white-eye, the only other Bornean white-eye that is uniformly yellow or olive, the Meratus white-eye is darker overall, with a longer bill and tail and thinner, less yellowish line above the lores. The lemon-bellied white-eye, found on small offshore islands off Borneo, and the Wakatobi white-eye, found on offshore islands off southwestern Sulawesi, are a much brighter yellow than the Meratus white-eye's deep olive-green appearance. [6]

Vocalisations

The song of the Meratus white-eye is one to three second long "warbling series of high-pitched short notes, ending with a faster, lower-pitched jumble". The white-eye's usual call is a high, "buzzy" 'zip'. Spectrograms of the songs of Meratus and lemon-bellied white-eyes show the Meratus white-eye's calls being consistently higher-pitched and having shorter "phrases". [2] Songs are mostly given early in the morning at daybreak. [6]

Distribution and habitat

The species is endemic to the Meratus Mountains in Indonesian Borneo, where it has been recorded from Mount Besar and Mount Karokangen. It inhabits the mid and lower storeys of closed-canopy montane forests and has been recorded above 1,300 m (4,300 ft). Its upper elevational range is not known for certain; the highest point in its range is 1,901 m (6,237 ft) on Mount Besar, but Meratus white-eyes have only been observed up to 1,600–1,650 m (5,250–5,410 ft). The species is assumed to be non-migratory. [6]

Ecology and conservation

Most aspects of the Meratus white-eye's ecology are unknown. It diet is unknown, but it has it has been seen in mixed-species foraging flocks with other insectivores. Foraging takes place in the lower and middle stories of the forest, with white-eyes probing the underside of moss hanging from twigs and petioles while hanging upside-down. Flocks of Meratus white-eyes can have up to 40 birds. No information on breeding is known, but presumed juveniles have been seen in the second week of July. [6]

The Meratus white-eye is classified as being of least-concern by the International Union for Conservation of Nature (IUCN) on the IUCN Red List. [1] It has a very small range and the authors of the study describing it recommended it be assessed as vulnerable due to its restricted distribution and pressure due to the songbird trade. [2] The species' abundance has not been formally quantified, but it is thought to be locally common within the small area it inhabits. [1] Although low-elevation forest in the Meratus white-eye's range has been heavily deforested, the species does not occur below 1,300 m (4,300 ft), [6] so habitat loss within its habitat is likely negligible in the decade before 2022. Consequently, the species' population is thought to be stable. [1] However, forests inhabited by the species are likely disturbed at moderate levels by humans harvesting forest products. [6]

The species is also threatened by the Indonesian trade in songbirds, having first been recorded from local songbird markets in 2021. Although this threat is not currently considered very severe, other Zosterops white-eyes have been popular in Indonesia and consequently the species requires monitoring. [1] Anecdotal reports from the Meratus Mountains have found that increasing ecotourism for birdwatching in the region may reduce incentives to poach birds. [8]

The species is not protected by Indonesian law and does not occur in any protected areas; [1] its range overlaps with a single protected area, the Pleihari Martapura Wildlife Reserve, which does not cover its altitudinal range. The Meratus Mountains it inhabits are designated as an Important Bird Area by BirdLife International. [6] Recommended conservation measures for the species include surveys to accurately estimate its population, finding the demand for the species in the songbird trade, and finding suitable tracts of habitat to protect. [1]

Related Research Articles

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Zosterops is a genus of passerine birds containing the typical white-eyes in the white-eye family Zosteropidae. The genus has the largest number of species in the white-eye family. They occur in the Afrotropical, Indomalayan, and Australasian realms. Typical white-eyes have a length of between 8 and 15 cm. Their most characteristic feature is a conspicuous white feather ring around the eye, though some species lack it. The species in this group vary in the structural adaptations of the tongue. The Zosterops [griseotinctus] group is an example of a "great speciator" inhabiting a vast area and showing a remarkable morphological differentiation on islands, some of which maybe as close as 2 km (1.2 mi) apart.

<span class="mw-page-title-main">Indian white-eye</span> Species of bird

The Indian white-eye, formerly the Oriental white-eye, is a small species of passerine bird in the white-eye family. It is a resident breeder in open woodland on the Indian subcontinent. They forage in small groups, feeding on nectar and small insects. They are easily identified by the distinctive white eye-ring and overall yellowish upperparts. The range previously extended eastwards to Southeast Asia, Indonesia and Malaysia. Their name was recently changed due to previous members of Zosterops palpebrosus in Southeast Asia being renamed to a new species, making the Indian White-eye a more geographically accurate term for this species.

<span class="mw-page-title-main">Chivi vireo</span> Species of bird from South America

The chivi vireo is a small South American songbird in the family Vireonidae. It was formerly considered a subspecies of the red-eyed vireo. It is usually green to yellow-green in color with off-white underparts, and a gray crown. It has a whitish supercilium extending over its ear coverts, and its lores are dull gray in color. The chivi vireo has nine subspecies. It is found throughout most of northern, eastern and central South America, only being absent from southern Chile and southern Argentina. It inhabits multiple types of habitat across its range, and appears to adjust well to slightly disturbed habitat. The chivi vireo is mainly resident, but at least two of the subspecies inhabiting the south of its range are known to be migratory.

<span class="mw-page-title-main">Warbling white-eye</span> Species of bird

The warbling white-eye is a small passerine bird in the white-eye family. The specific epithet is occasionally written japonica, but this is incorrect due to the gender of the genus. Its native range includes much of East Asia, including the Russian Far East, Japan, Indonesia, Korea, and the Philippines. It has been intentionally introduced to other parts of the world as a pet and as pest control, with mixed results. As one of the native species of the Japanese islands, it has been depicted in Japanese art on numerous occasions, and historically was kept as a cage bird.

<span class="mw-page-title-main">Mauritius olive white-eye</span> Species of bird

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<span class="mw-page-title-main">Bornean stubtail</span> Species of bird

The Bornean stubtail is a species of bird in the cettiid warbler family Cettiidae. It is endemic to the island of Borneo, where it inhabits forest floors and undergrowth in montane forests at elevations of 750–3,150 m (2,460–10,330 ft). It is a small, short-tailed warbler, measuring 9.5–10 cm (3.7–3.9 in) in length and having an average mass of 10.4 g (0.37 oz). The tops of the head and the upperparts are brown, with whitish underparts that turn grey at the sides of the breast and the flanks. The supercilium is long and buffish-brown, with an equally long dark grey eyestripe and a thin yellow eye-ring. Both sexes are similar.

<span class="mw-page-title-main">White-fronted falconet</span> Species of bird

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<span class="mw-page-title-main">Hose's broadbill</span> Species of bird endemic to Borneo

Hose's broadbill is a species of bird in the family Calyptomenidae. It was described by the British naturalist Richard Bowdler Sharpe in 1892 and is named after the British zoologist Charles Hose, who collected the holotype of the species. It is 19–21 cm (7.5–8.3 in) long, with females weighing 92 g (3.2 oz) on average and males weighing 102–115 g (3.6–4.1 oz). Males are bright green and have conspicuous black spots on the wings, black markings on the head, blue underparts, black flight feathers, and a large green tuft covering most of the bill. Females have smaller forehead tufts, lime-green underparts with sky blue instead of azure blue on the undertail coverts, and lack black markings on the head, except for a black spot in front of the eye.

<span class="mw-page-title-main">Mountain blackeye</span> Species of bird endemic to Borneo

The mountain blackeye, sometimes referred to as the olive blackeye or simply black-eye, is a species of passerine bird in the family Zosteropidae. It is endemic to the highest mountains on the island of Borneo. It is known from both Malaysian states on the island, and four of the five Indonesian provinces, but has never been recorded in Brunei. Typically found at elevations above 1,800 m (5,900 ft), the mountain blackeye sometimes moves to lower altitudes during periods of drought. There are four subspecies, which show clinal variations in size and coloring. Birds in the north are largest, darkest, and proportionately longer-tailed, while those further south are smaller, paler, and proportionately shorter-tailed. Adults are dark olive-green with a sharply-pointed, bright yellow-orange bill and a small dark mask connecting black lores with a black eye-ring. The subspecies show varying amounts of yellow in their plumage, particularly on the face and underparts. Young birds resemble their parents, but have less brightly colored bills.

<span class="mw-page-title-main">Black-sided flowerpecker</span> Species of bird

The black-sided flowerpecker, also known as the Bornean flowerpecker, is a species of bird in the family Dicaeidae. It is endemic to the island of Borneo, where it is found in the mountains, primarily above 1,000 m (3,300 ft) in elevation. The species is sexually dimorphic. The male has glossy blue-black upperparts, with a scarlet throat and breast, a dark grey upper belly, olive flanks, a white lower belly, and a buffy vent and undertail coverts. The female is olive-green above and greyish below, with buffy flanks and a whitish throat. It inhabits a range of forest habitats, including primary and secondary montane forest, kerangas forest, and scrub, and is also occasionally found in gardens. It feeds primarily on small fruits—particularly mistletoe berries—as well as seeds, nectar, and various invertebrates. It builds a nest of moss, camouflaged on the outside with lichens and lined with the pith of tree ferns. The International Union for Conservation of Nature rates it as a species of least concern. Though its numbers have not been quantified, the black-sided flowerpecker is said to be common throughout much of its range, and any declines are not thought to be precipitous. However, destruction of forest for palm plantations may impact it.

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<span class="mw-page-title-main">Lemon-bellied white-eye</span> Species of bird

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<span class="mw-page-title-main">Meratus Mountains</span> Mountain range in South Kalimantan, Borneo

The Meratus Mountains is a mountain range in the Indonesian province of South Kalimantan; it is located on Borneo island. The mountains run in a north-south arc that divides South Kalimantan province into two almost equal parts. Its highest peak is Mount Besar at 1,901 metres elevation.

<span class="mw-page-title-main">Chestnut-hooded laughingthrush</span> Species of bird endemic to Borneo

The chestnut-hooded laughingthrush is a species of bird in the laughingthrush family Leiothrichidae endemic to Borneo. Described by the British ornithologist Richard Bowdler Sharpe as a distinct species in 1879, it was subsequently considered a subspecies of the chestnut-capped laughingthrush until 2007, when it was again raised to species status by the ornithologists Nigel Collar and Craig Robson. It is 22–24 cm (8.7–9.4 in) long, with a chestnut brown head and chin, with grey feathering on the top of the head. The upperparts and the side of the neck are slaty-grey, with a long white wing patch. The throat, breast, and upper belly are dull yellowish-brown, with purer grey flanks and a reddish-brown vent, lower belly, and thighs. It has a yellow half eye-ring behind and below the eye, while the tail has a blackish tip. Both sexes look similar, while juveniles are duller than adults.

<span class="mw-page-title-main">Sangkar white-eye</span> Species of bird

The sangkar white-eye is a bird species in the family Zosteropidae. It is also known as the Sunda white-eye. It is found in forested habitats on the Indonesian islands of Java and Bali. In Java it is typically found at elevations between 200–1,600 m (660–5,250 ft), but it sometimes occurs at lower elevations as well.

<span class="mw-page-title-main">Meratus blue flycatcher</span> Species of bird

The Meratus blue flycatcher is a species of bird in the Old World flycatcher family, Muscicapidae. The species was described in 2021 by the Indonesian ornithologist Mohammed Irham and his colleagues, based on genetic, morphological, and vocal differences with other Cyornis flycatchers. It is endemic to the Meratus Mountains of Indonesian Borneo, where it has been recorded only from Mount Besar. It is most common at elevations between 900 and 1,300 m and inhabits montane rainforest, secondary forest, and rubber plantations. It is sexually dimorphic like other species in its genus; males have blue upperparts, iridescent blue patches on the forehead and shoulders, and orange-and-white underparts, while females have gray-brown heads and upperparts. They have a length of 15.7–16.0 cm (6.2–6.3 in); males weigh 18.5–19.75 g (0.653–0.697 oz) and females weigh 15.75–20.0 g (0.556–0.705 oz).

<span class="mw-page-title-main">Wangi-wangi white-eye</span> Species of songbird

The Wangi-wangi white-eye, locally known as sui, is a species of songbird in the white-eye family. It is endemic to a single island, Wangi-wangi Island, in the Wakatobi Islands, Indonesia.

References

  1. 1 2 3 4 5 6 7 BirdLife International (2022). "Zosterops meratusensis". IUCN Red List of Threatened Species . 2022: e.T216557421A217158261. Retrieved 23 March 2024.
  2. 1 2 3 4 5 6 Irham, M.; Haryoko, T.; Shakya, S.B.; Mitchell, S.L.; Burner, R.C.; Bocos, C.; Eaton, J.A.; Rheindt, F.E.; Suparno, S.; Sheldon, F.H.; Prawiradilaga, D.M. (2022). "Description of two new bird species from the Meratus Mountains of southeast Borneo, Indonesia". Journal of Ornithology. 163 (2): 575–588. doi:10.1007/s10336-021-01937-2.
  3. 1 2 Eaton, J. A.; Mitchell, S. L.; Navario Gonzalez Bocos, C.; Rheindt, F. E. (2016). "A short survey of the Meratus Mountains, South Kalimantan province, Indonesia: two undescribed avian species discovered". BirdingASIA. 26: 108–111.
  4. Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 414. ISBN   978-1-4081-2501-4 via Internet Archive.
  5. 1 2 Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (December 2023). "Sylviid babblers, parrotbills, white-eyes". IOC World Bird List Version 14.1. International Ornithologists' Union. Retrieved 23 March 2024.
  6. 1 2 3 4 5 6 7 8 9 10 11 Kirwan, Guy M. (2022-10-25). Billerman, Shawn M.; Keeney, Brooke K.; Rodewald, Paul G.; Schulenberg, Thomas S. (eds.). "Meratus White-eye (Zosterops meratusensis)". Birds of the World. Cornell Lab of Ornithology. doi:10.2173/bow.merwhe1.01 . Retrieved 2024-03-21.
  7. Shakya, Subir B.; Haryoko, Tri; Burner, Ryan C.; Prawiradilaga, Dewi M.; Sheldon, Frederick H. (2018). "Preliminary assessment of community composition and phylogeographic relationships of the birds of the Meratus Mountains, south-east borneo, Indonesia". Bulletin of the British Ornithologists' Club. 138 (1): 45–66. doi: 10.25226/bboc.v138i1.2018.a6 . ISSN   0007-1595.
  8. Eaton, James A.; Yordan, Khaleb; Hutchinson, Robert O. (2023). "'Meratus Flowerpecker': yet another undescribed species from the Meratus Mountains, South Kalimantan, and further notes on other undescribed taxa". BirdingASIA. 40: 24.