{{short description|Species of bird}} {{good article}} {{Speciesbox | image = 2M3A6919 - White-browed Nuthatch - Sitta victoriae (cropped).jpg | status = EN | status_system = IUCN3.1 | status_ref = <ref name="iucn status 13 November 2021">{{cite iucn |author=BirdLife International |date=2016 |title=''Sitta victoriae'' |volume=2016 |article-number=e.T22711167A94281752 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22711167A94281752.en |access-date=13 November 2021}}</ref> | taxon = Sitta victoriae | authority = Rippon, 1904 | synonyms = * ''Sitta himalayensis victoriae'' <small>(Rippon, 1904)</small> | synonyms_ref = <ref>{{Cite journal |last1=Dickinson |first1=E. C. |author1-link=Edward C. Dickinson |last2=Loskot |first2=V. M. |last3=Morioka |first3=H. |last4=Somadikarta |first4=S. |author4-link=Soekarja Somadikarta |last5=van den Elzen |first5=R. |name-list-style=amp |date=December 2000 |url=https://www.researchgate.net/publication/268077056 |title=Systematic notes on Asian birds. 66. Types of the Sittidae and Certhiidae |journal=Zoologische Mededelingen |volume=80 |issue=5 |pages=287–310 |oclc=1176345828 |via=ResearchGate}}</ref> | range_map = Sitta victoriae distribution.svg | range_map_caption = White-browed nuthatch range }}
The '''white-browed nuthatch''' ('''''Sitta victoriae'''''), also known as the '''Victoria nuthatch''', is a species of bird in the family Sittidae. It is a small nuthatch, measuring {{convert|11.5 |cm|in|abbr=on}} in length and without sexual dimorphism. Like many other nuthatches, the {{birdgloss|upperparts}} are greyish blue, contrasting with white underparts on the throat, cheeks, and breast and orange on the flanks, belly, and lower abdomen. Its white supercilium makes it easy to distinguish it from the white-tailed nuthatch (''S. himalayensis''), which is a close species in the systematic and geographical sense. Little is known about its ecology, but it feeds on small insects found among bark and lichens, and breeding occurs around April.
The white-browed nuthatch is endemic to Nat Ma Taung, also known as Mount Victoria, in the southern Chin Hills of Myanmar. It inhabits old oak groves at high elevations, generally above {{Convert|2600|m|ft|abbr=on}}. The population poorly known but is estimated to be a few thousand individuals. It threatened by habitat destruction by fire and human pressure. For these reasons, the International Union for the Conservation of Nature considers the bird to be an "endangered species."
== Taxonomy == The white-browed nuthatch was described in 1904 under its current binomial name, ''S. victoriae'', by the British ornithologist and Lieutenant-Colonel George Rippon,<ref name="Rippon">{{cite journal|journal= Bulletin of the British Ornithologists' Club|last= Rippon|first= George|volume= 14|year=1904|pages=83–4|title=New birds from the southern Chin Hills, Burma|url=https://archive.org/details/bulletino101518991905brit?view=theater#page/n571/mode/2up|publisher=British Ornithologists' Club}}</ref> and the holotype is deposited in the British Museum.<ref name="British Museum">{{cite web |last1=Warren|first1= Rachel L M |volume=2| title=Type-specimens of birds in the British Museum (Natural History): British Museum (Natural History). Department of Zoology. | website=Internet Archive | date=20 Dec 2021 | url=https://archive.org/details/typespecimensofb02brit | access-date=26 Dec 2021}}</ref> British ornithologist Lieutenant H. Wood, who visited Nat Ma Taung, also known as Mount Victoria; thus, the species was called ''Sitta victoriae'',<ref name="Jobling">{{cite journal|journal= Helm Dictionary of Scientific Bird Names|last= Jobling|first= James|year=2010|pages=415–432|title=The Helm dictionary of scientific bird names [electronic resource]: from aalge to zusii|url=https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling/page/n401/mode/2up|publisher=Christopher Helm|isbn=978-1-4081-3326-2}}</ref> visited nearby during the winter of 1901–1921, and was the first to explore the Chin hills ornithologically. Rippon then spent several months on Nat Ma Taung in 1904, collecting a large number of specimens in response to Wood's initial findings.<ref name="auto1"/> It is most likely phylogenetically related to the white-tailed nuthatch (''S. himalayensis''), prompting Richard Meinertzhagen (in 1927), Ernst Mayr (in 1941), and Charles Vaurie (in 1957) to treat ''S. victoriae'' as a subspecies of ''S. himalayensis''.<ref name="Vaurie 1957">{{cite journal|journal= American Museum Novitates|last= Vaurie|first= Charles|issue= 1854|year=1957|pages=1–26|title= Systematic notes on Palearctic birds. No. 29, The subfamilies Tichodromadinae and Sittinae|hdl= 2246/3596|url=https://digitallibrary.amnh.org/handle/2246/3596|issn=1937-352X|oclc=47720325}}</ref><ref name=" The Birds of South-eastern Tibet">{{cite book |last1=Ludlow |first1=Frank |last2=Boyd Kinnear |first2=Norman |title= The Birds of South-eastern Tibet |year=1944 |pages= 43–86}}</ref> However, Vaurie pointed out that there was no evidence of intergradation between the nuthatch from Nat Ma Taung and the nuthatch from the Mizo Hills in the Himalayas, 180 kilometers northeast of Nat Ma Taung.<ref name="Vaurie 1957"/><ref name="Harrap p. 126">{{cite book |last=Harrap |first=Simon |others=Illustrated by David Quinn |title=Tits, Nuthatches and Treecreepers |date=1996|editor=Christopher Helm |publisher=Princeton University Press |page=126|isbn=0-7136-3964-4}}</ref> In 1957, British ornithologist Simon Harrap suggested that the small size, solid {{birdgloss|undertail coverts}}, and marked white supercilium may indicate close relationships with the Yunnan nuthatch (''Sitta yunnanensis'').<ref name="Harrap p. 126"/> The German ornithologist Hans Edmund Wolters proposed the division of the genus ''Sitta'' into subgenera in 1975-1982, with white-browed nuthatch placed in ''Sitta'' subgenus ''Mesositta''.<ref name="Matthysen 2010 p. ">{{cite book | last=Matthysen | first=Erik | title=The Nuthatches | publisher=A & C Black | publication-place=London | year=2010 | isbn=978-1-4081-2870-1 | oclc=727646681 | page=}}</ref> According to the International Ornithological Congress and Alan P. Peterson, no subspecies are distinguished.<ref name="IOC World Bird List – Version 11.2">{{cite web | title=Nuthatches, Wallcreeper, treecreepers, mockingbirds, starlings, oxpeckers – IOC World Bird List | website=IOC World Bird List – Version 11.2 | url=http://worldbirdnames.org/bow/nuthatch | access-date=26 Dec 2021}}</ref><ref name="Zoonomen Nomenclature Resource Page 2002">{{cite web | title=World Birds Taxonomic List: Genera and species with citations. | website=Zoonomen Nomenclature Resource Page | date=1 Mar 2002 | url=http://www.zoonomen.net/avtax/pa48.html | access-date=26 Dec 2021}}</ref>
Päckert and colleagues (2020) studied the complete circum-Tibetan group of nuthatches, which were sister to ''S. himalayensis'' and ''S. victoriae''. Surprisingly, a deep split between three specimens of ''S. himalayaensis'' equaled interspecific divergences among species of clade.<ref name="Packert2020">{{ cite journal | last1=Päckert | first1=M. | last2=Bader-Blukott | first2=M. | last3=Künzelmann | first3=B. | last4=Sun | first4=Y.-H. | last5=Hsu | first5=Y.-C. | last6=Kehlmaier | first6=C. | last7=Albrecht | first7=F. | last8=Illera | first8=J.C. | last9=Martens | first9=J. | date=2020 | title=A revised phylogeny of nuthatches (Aves, Passeriformes, ''Sitta'') reveals insight in intra- and interspecific diversification patterns in the Palearctic | journal=Vertebrate Zoology | volume=70 | issue=2 | pages=241–262 | doi=10.26049/VZ70-2-2020-10 | doi-access=free }}</ref> Within the ''Sitta europaea'' group, the white-tailed nuthatch and white-browed nuthatch are not included in the study, but appear to be basal.<ref name="Packert2020"/> {{clade gallery |width=200; |height=140; |cladogram1= {{clade |1={{clade |1=White-browed nuthatch (''Sitta victoriae'') |2=White-tailed nuthatch (''Sitta himalayensis'') }} |2={{clade |1=Eurasian nuthatch (''Sitta europaea'') |2={{clade |1=Chestnut-vented nuthatch (''Sitta nagaensis'') |2={{clade |1=Kashmir nuthatch (''Sitta cashmirensis'') |2={{clade |1=Indian nuthatch (''Sitta castanea'') |2={{clade |1=Chestnut-bellied nuthatch (''Sitta cinnamoventris'') |2=Burmese nuthatch (''Sitta neglecta'') }} }} }} }} }} }} |caption1=Phylogenetic tree detail |header1=Nuthatch phylogenic detail according to Packert, ''et al.'' (2020): <ref name="Packert2020"/> }}
== Description == [[File:Comparison of tails of Sitta himalayensis & Sitta victoriae.svg|left|thumb|180px|Comparison of the tail of the white-tailed nuthatch (''S. himalayensis''), left, and the white-browed nuthatch (''S. victoriae''), right.]] The white-browed nuthatch is a small nuthatch, measuring {{convert|11.5|cm|in|abbr=on}} in length.<ref name="Harrap p. 125">{{cite book |last=Harrap |first=Simon |others=Illustrated by David Quinn |title=Tits, Nuthatches and Treecreepers |date=1996|editor=Christopher Helm |publisher=Princeton University Press |page=125|isbn=0-7136-3964-4}}</ref> The folded wing measures {{convert|68|–|73|mm|in|abbr=on}} for the male, {{convert|67|–|69|mm|in|abbr=on}} for the female. The tail is {{convert|36|–|37|mm|in|abbr=on}}, the {{Birdgloss|beak}} is {{convert|15|–|16.|mm|in|abbr=on}}, and the tarsus is {{convert|14|–|16.|mm|in|abbr=on}}. The weight is not known,<ref name="Harrap p. 126"/> but the Chinese nuthatch and the red-breasted nuthatch, which are also {{convert|11.5|cm|in|abbr=on}} in length, average {{convert|11.3|g|oz}} and {{convert|8|–|12.7|g|oz}}, respectively.<ref name="Harrap p. 142">{{cite book |last=Harrap |first=Simon |others=Illustrated by David Quinn |title=Tits, Nuthatches and Treecreepers |date=1996|editor=Christopher Helm |publisher=Princeton University Press |page=142|isbn=0-7136-3964-4}}</ref><ref name="Harrap p. 147">{{cite book |last=Harrap |first=Simon |others=Illustrated by David Quinn |title=Tits, Nuthatches and Treecreepers |date=1996|editor=Christopher Helm |publisher=Princeton University Press |page=147|isbn=0-7136-3964-4}}</ref>
The {{birdgloss|upperparts}} are dull bluish-grey. The underparts are white from the throat and lower chest, but the belly is orange, with the underside and undertail light red and the flanks darker. It has a white forehead, eyebrows, and lore, and a black line at the back of the eye, thickening backwards on the nape.<ref name="Harrap p. 40-41">{{cite book |last=Harrap |first=Simon |others=Illustrated by David Quinn |title=Tits, Nuthatches and Treecreepers |date=1996|editor=Christopher Helm |publisher=Princeton University Press |pages=40–41|isbn=0-7136-3964-4}}</ref> The cheeks are as white as the throat but the back of the cheek is orange, with a white patch on the parotic coverts. No sexual dimorphism was found, and the juveniles could be distinguished by the lighter orange-red flanks.<ref name="Harrap p. 125"/> The bill is black at the tip and slate grey otherwise; the culmen and lower mandible are iris red-brown or dark brown, paler. The thighs are grey, and the legs are dull, yellowish-brown, or olive-brown.<ref name="Harrap p. 126"/>
The white-browed nuthatch can be confused with the white-tailed nuthatch, which can inhabit the same areas but which is rare where white-browed nuthatch lives.<ref name="auto1">{{Cite web|last=Zaw Niang|first=Thet|date=2003|title=Ecology of the White-browed Nuthatch Sitta victoriae in Natmataung National Park, Myanmar, with notes on other significant species|url=https://static1.squarespace.com/static/5c1a9e03f407b482a158da87/t/5c1ff0b46d2a734eed08ee1e/1545597108810/Naing-Nuhatch.pdf|access-date=26 December 2021}}</ref> Adults in their fresh plumage have a narrow whitish supercilium extending to the back of the ear-coverts.<ref name="Harrap p. 126"/> The central tail feathers of white-browed nuthatch are light grey at the tip and have white over most of their base, which is distinctive from the white-tailed nuthatch in which the white is relatively sparse.<ref name="Harrap p. 40-41"/> It has a narrow black {{birdgloss|eyestripe}} that becomes much wider on the upper mantle.<ref name="Harrap p. 126"/> The white-browed nuthatch can also be recognized by its white eyebrows and forehead and the strong contrast between the white of the breast and the dark red flanks. Finally, the beak is shorter and thinner.<ref name="Harrap p. 125"/>
== Ecology and behaviour == right|thumb|White-browed nuthatch on a tree branch.
===Vocalizations=== {{Birdsong|image=SittaVictoriae.png|species=''Sitta victoriae''|url=https://xeno-canto.org/explore?query=Sitta%20victoriae}} The call is produced at irregular intervals, and consists of a simple ''pit'' or ''plit''. The white-browed nuthatch also emits an insistent ''pii, pii, pii...'' with 2.5 to 3.5 notes per second, produced more or less regularly. Harrap reports a possible song, consisting of 9 to 12 units at 9 notes per second and consisting of a ''whi-whi-whi...''<ref name="Harrap p. 125"/> The classical song is a slow and soft trill composed of ''tuwi'' couplets emitted at the rate of 4 couplets per second, and produced in a stanza of 1.5 seconds rising in intensity ''tuwi-tuwi-tuwi-tuwi-tuwi-tuwit''.<ref name="HBW">{{cite journal | last=Harrap | first=Simon | title=White-browed Nuthatch (Sitta victoriae), version 1.0 | journal=Birds of the World | date=4 Mar 2020 | doi=10.2173/bow.whbnut1.01 | url=https://birdsoftheworld.org/bow/species/whbnut1/cur/introduction | access-date=26 Dec 2021 | page=| s2cid=216206236 | url-access=subscription }}</ref>
=== Food === The nuthatch is usually seen alone or in pairs. It feeds on small insects which it usually finds in the epiphytes growing on the oaks, or in hollows in the bark. It generally explores the outer branches, but can also prospect on the branches more inside the tree or on the trunk. The plant species prospected are ''Quercus semecarpifolia'' half the time, but ''Rhododendron arboreum'' is also exploited, as well as, to a lesser extent, ''Lyonia ovalifolia'', ''Lithocarpus dealbatus'', ''Pinus kesiya'', and ''Alnus nepalensis''.<ref name="auto1"/>
=== Breeding === Very little is known about its reproduction. Myanmar ornithologist Thet Zaw Naing observed three nests between mid-March and early April in 2002. Two of the nests were located in the cavity of an internal branch in a ''Quercus semecarpifolia'', {{cvt|4|m|ft}} and {{cvt|10|m|ft}} high; the third was placed in the trunk of a ''Rhododendron arboreum'', {{cvt|6|m|ft}} high. The first nest cited was dug by the female alone, and its entrance was not walled up with clay, unlike what several other nuthatch species do. Only females seem to feed the young. In April, three flocks were observed, each with two fledged young.<ref name="auto1"/>
== Distribution and habitat == [[File:Manaslu-Circuit Rhododendron.jpg|right|thumb|''Rhododendron arboreum'' can be visited by the nuthatch, both for food and for nesting.]] The white-browed nuthatch is endemic to western Myanmar.<ref name="IOC World Bird List – Version 11.2"/> It is currently found on Nat Ma Taung in the southern part of the Chin Hills, at nearly {{cvt|3070|m|ft}}, and {{cvt|22|km|mi}} further northwest in the spring of 1995 near Mindat.<ref name="Harrap p. 126"/><ref>{{Cite web|last=C. R. ROBSON, H. BUCK, D. S. FARROW|first=T. FISHER and B. F. KING|date=1998|title=A birdwatching visit to the Chin Hills, West Burma (Myanmar), with notes from nearby areas|url=https://static1.squarespace.com/static/5c1a9e03f407b482a158da87/t/5c1fbe040ebbe84faf306d74/1545584136696/Robson-Chin.pdf|access-date=26 December 2021}}</ref>
The white-browed nuthatch avoids the pure pine forests of ''Pinus kesiya'' and is found instead in lichen-covered old oak forests of the alpine level. Thus, it was observed at an altitude of over {{cvt|2600|m|ft}} in 1940 and over {{cvt|2700|m|ft}} in the spring of 1995.<ref name="Harrap p. 126"/> However, during the description of the species in 1904, Rippon reported that he collected six birds between {{cvt|2285–2745|m|ft}} altitude from 22 March to 30 April;<ref name="Ludlow pp. 348–389">{{cite journal | last=Ludlow | first=F. | title=The Birds of South-eastern Tibet | journal=Ibis | publisher=Wiley | volume=86 | issue=3 | date=1944 | issn=0019-1019 | doi=10.1111/j.1474-919x.1944.tb04094.x | pages=348–389}}</ref> there could therefore be seasonal altitudinal dispersion, with the birds leaving the higher altitudes during winter.<ref name="Harrap p. 126"/>
The white-browed nuthatch habitat consists mainly of ''Quercus semecarpifolia'' oaks, covered with epiphytic plants, lichens, mosses, orchids, and ferns.<ref name="auto1"/>
== Status and threats == The white-browed nuthatch is one of four endemic bird species in Myanmar, the others being the hooded treepie (''Crypsirina cucullata''), Burmese bush lark (''Mirafra microptera'') and white-throated babbler (''Turdoides gularis''). The counts of the species mentioned in the literature are very patchy: 14 birds were observed in 1995, then five over two weeks in April 2000, and 45 during four months of fieldwork in 2001-2003. In 2007, surveys in the Chin Hills did not find any observations of this nuthatch, suggesting that the species is strictly endemic in the Nat Ma Taung region. These observations, combined with density and distribution data, indicate a population of 2,500 to 10,000 mature individuals, for a total of 3,500 to 15,000 individuals.<ref name="iucn status 13 November 2021"/>
On Nat Ma Taung, the forest has been completely cleared up to {{cvt|2000|m|ft}}, and the remaining habitats at {{cvt|2000–2500|m|ft}} are severely degraded. Nearly 12,000 people live in Natmataung National Park, and trapping and fires are adding to the threats to the species. The population, estimated at a few thousand individuals, is declining. The species is legally protected by a 1994 Myanmar law (Protection of Wildlife and Conservation of Natural Areas Law), but no protective measures are implemented, including discouraging the destruction of its habitat.<ref name="iucn status 13 November 2021"/> The range is estimated at {{Convert|820|km2|sqmi|abbr=on}} by BirdLife International.<ref name="BirdLife International">{{cite web | title=White-browed Nuthatch (Sitta victoriae) - BirdLife species factsheet | website=BirdLife International | url=http://datazone.birdlife.org/species/factsheet/22711167| access-date=26 Dec 2021}}</ref> For these reasons, the species is considered endangered by the International Union for the Conservation of Nature.<ref name="iucn status 13 November 2021"/>
==References== {{Reflist}}
{{Taxonbar|from=Q534380}}
white-browed nuthatch Category:Endemic birds of Myanmar white-browed nuthatch Category:Taxonomy articles created by Polbot