Japanese Society Finch: from Loxia to Lonchura
Lonchura striata domestica
By Dirk Van den Abeele
Ornitho-Genetics VZW
De Nederlandse versie van dit artikel kan je hier lezen
The Japanese Society Finch is known worldwide by several names, such as Moineau du Japon, Bengalese finch, society finch, Japanisches Mövchen, and others. For a long time, however, there was much uncertainty about the origin and scientific classification of this bird. It was formerly assumed to be a complex hybrid of several estrildid finch species. Today, the Japanese Society Finch is generally regarded as a domesticated form of the White-rumped Munia (Lonchura striata) and belongs to the family of estrildid finches (Estrildidae). Anyone wishing to understand the Japanese Society Finch and its history cannot ignore the White-rumped Munia, because this species forms the basis of the Japanese Society Finch.
For clarity, we should also mention that there is a seabird officially called the Black-tailed Gull, Larus crassirostris, which is sometimes referred to in Dutch as the “Japanese gull.” In aviculture, however, the name “Japanese Society Finch” almost always refers to the popular cage bird. In this article, therefore, we use the term exclusively for the domesticated form of the White-rumped Munia (Lonchura striata) from the genus Lonchura.
Back to the basis: the White-rumped Munia
According to the most widely used modern taxonomy, the genus Lonchura contains about 28 recognized species. The exact number of subspecies is difficult to state, because it changes regularly as a result of new genetic studies and also depends on which taxonomic list is followed. Some estrildid finch species have no subspecies, while others have many. Taken together, there are certainly more than 60.
Lonchura striata, or the White-rumped Munia, measures 10 to 12 centimetres, including its characteristic long pointed tail. The back, wings, and head are dark brown. The breast is also brown, but often lighter in tone than the wing coverts. The underside of the belly is white to off-white. The bill is dark grey, and the claws and legs are dark.
The White-rumped Munia is generally regarded as a social bird. In the wild, they usually live in small groups, and several pairs build their nests close to one another, especially in places where there is sufficient food and shelter.
Even so, they are not pronounced colonial breeders like some seabirds, where hundreds of nests are packed closely together. In Lonchura striata, it is more a loose colonial nesting habit: pairs tolerate each other’s proximity well and often nest in the same shrubs, reed beds, or bamboo stands. There are even reports of pairs breeding in the same nest and jointly caring for the young [1]. The domesticated form, the Japanese Society Finch, has retained this social character. For that reason, Japanese Society Finches can usually be kept together in groups in aviculture without problems, and several pairs often breed at the same time in the same aviary.
Its range extends across South, Southeast, and East Asia, specifically in the following countries: Bangladesh, Bhutan, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Singapore, Sri Lanka, Taiwan, China, Thailand, and Vietnam. This is said to cover an area of more than 14,500,000 km². Thanks to this wide distribution, the species is fortunately not threatened with extinction in the wild [2].
Their habitat consists mainly of grasslands and savannas with shrubs, bamboo growth, forest edges and clearings in light woodland, agricultural areas such as rice fields, as well as gardens and human settlements. Yet they usually prefer areas with sufficient tall grass, reeds, or shrubs, because there they find food and can build their dome-shaped nests. They most prefer to live close to water or in humid regions.
Coccothraustes borbonica
While the first reports of the Japanese Society Finch date only from 1860, the story of the White-rumped Munia begins exactly a century earlier. In 1760, the French zoologist Mathurin Jacques Brisson (1723–1806) introduced this bird in the third volume of his extensive work Ornithologie (full title: Ornithologie, ou, Méthode contenant la division des oiseaux en ordres, sections, genres, especes & leurs variétés).
In this bilingual description (French and Latin), he called the bird in French ‘Le gros-bec de l’Isle de Bourbon’ (the grosbeak of Bourbon Island), and gave it the corresponding Latin name Coccothraustes borbonica. Coccothraustes is a combination of the Greek words kokkos (stone or seed) and thrauo (to break), meaning “kernel-breaker,” while borbonica means “from Bourbon Island,” the historical name of Réunion Island in the Indian Ocean. In other words: “kernel-breaker of Bourbon.”
It is a fairly detailed description, and Brisson referred to a drawing later in the book. I provide a translation here:
…On Bourbon Island he is called JACOBIN. He is hardly larger than a wren. His length from the tip of the bill to the tip of the tail is three inches eight lines, and to the tips of the claws three inches five lines.
His bill measures five lines from its tip to the corners of the mouth; his tail is sixteen lines long.
his leg measures five and a half lines; and the middle of the three front toes, together with the claw, is six lines long: the outer toes are much shorter; and the hind toe is slightly longer than the latter.
He has a wingspan of five inches ten lines; and when folded, his wings do not quite reach halfway along the length of the tail. The head, the upper part of the neck, and the back are covered with brown feathers whose shafts are rusty brown. The scapulars, the upper wing coverts, and the upper tail coverts are of the same colour and also have rusty-brown shafts. The brown is darker, even blackish, on the crown and all around the base of the bill. The throat and lower part of the neck are blackish. The breast, belly, flanks, and rump are white. The underwing coverts are rusty white; the undertail coverts and the legs are brown. The wing feathers are dark brown, and their inner webs are edged with rusty white from the base to about two-thirds of their length. The tail is composed of twelve black-brown feathers. The outer feathers are slightly shorter than those in the middle. The upper mandible is blackish and the lower one grey. The legs and claws are blackish.
He is found on Bourbon Island, whence he was sent to Mr de Réaumur by Mr de Lanux…
What is immediately striking is that Brisson made a geographical mistake in his description. He thought that the bird he examined came from Réunion Island. Later, however, it became clear that the specimen probably came from Sri Lanka. Moreover, the bird does not occur naturally in Africa or on the African islands at all.
The measurements in the text are given in lines. A line (French: ligne) is an old unit of length that was used extensively throughout Europe before the metric system, with metres and centimetres, was introduced at the end of the eighteenth century. It was, in effect, the “millimetre” of earlier times: the standard unit for accurately describing very small things such as a bird’s bill or leg.
The exact length could vary slightly from country to country or region to region, but the relationship between the units was almost always based on the duodecimal system:
- 1 foot consisted of 12 inches.
- 1 inch consisted of 12 lines.
If we convert that to our metric system:
- A French inch (pouce) was 2.71 cm.
- A French line (ligne) was one twelfth of that: exactly 2.26 millimetres, or 0.226 cm.
For example, the text states that the bill of the White-rumped Munia (the grosbeak of Bourbon Island) measures 5 lines from the tip to the corner of the mouth. Converted to today’s units, that is: 5 × 2.26 mm = 11.3 mm. The bill of this little bird was therefore just over one centimetre long. This fits perfectly with the description that the bird is “hardly larger than a wren.”
For his description, Brisson used a — presumably mounted — specimen from the well-known natural history collection of René-Antoine Ferchault de Réaumur (1683–1757). Réaumur was not only a collector, but also Brisson’s employer. In October 1749 he hired him as supervisor of his cabinet. The Académie royale des Sciences paid Brisson an annual salary of 600 livres for this work [3].
Although Brisson used Latin names, he did not yet apply a consistent binomial system (the two-part naming system consisting of a genus and species name). Because his names were often long descriptive phrases, or polynomials, the International Commission on Zoological Nomenclature (ICZN) decided that Brisson’s species names from this work are not valid for modern taxonomy. As a result, the name Coccothraustes borbonica never became an officially recognized scientific name. The genus name Coccothraustes itself, however, did survive and is today the official scientific genus name of the Hawfinch.
1766. Loxia striata
In 1766, the Swede Carl Linnaeus (1707–1778) gave the White-rumped Munia its first officially accepted scientific description and name in the twelfth edition of his Systema Naturae: Loxia striata. The description is very brief. In fact, he took part of Brisson’s description, placed it within his own binomial system, and thus received credit for the official naming. Brisson had incorrectly stated that the bird came from Bourbon Island (present-day Réunion), and Linnaeus blindly adopted this geographical error. In his own description he also referred to Brisson’s text and illustration. He placed the bird in the genus Loxia, a genus in which Linnaeus at that time included many thick-billed birds. Today, the genus Loxia contains the crossbills (true finches), whereas the White-rumped Munia is an estrildid finch (Estrildidae).
1849. Munia striata
Edward Blyth (1810–1873), an English researcher who spent much of his life working in India, officially published the name Munia striata for the White-rumped Munia in 1849 in his well-known work Catalogue of the Birds in the Museum Asiatic Society (the catalogue of the museum in Calcutta, India, where he was curator at the time). The genus Munia had been established in 1836 by the British ornithologist Brian Houghton Hodgson (1801–1894). This name remained common for a long time among ornithologists and bird traders. Today, the genus Munia is no longer officially accepted: biologists have largely merged the genus Munia into the genus Lonchura.
1851. Uroloncha striata
The genus Uroloncha was established in 1851 by the German ornithologist Jean Louis Cabanis (1816–1906). He introduced this new genus in 1851 in his influential scientific work Museum Heineanum. In fact, that book was an overview of the bird collection of Ferdinand Heine, a German jurist and collector. Ferdinand Heine senior (1809–1894) assembled a huge bird collection during his lifetime. It consisted of some 12,000 specimens (including skins, eggs, nests, and skeletons), representing no fewer than 5,187 different bird species. Jean Louis Cabanis had the honour of cataloguing these birds. In doing so, he separated a number of estrildid finches from other genera because he believed that finches with a clearly graduated, pointed tail (such as the White-rumped Munia) deserved their own group.
The name Uroloncha is therefore a combination of the Greek words for “tail” (oura) and “lance/spear” (lonkhe) — a direct reference to that typical pointed tail shape.
1860. Bengalese finch
The first reports of “Bengalese finches” or Japanese Society Finches in Europe appeared only from the 1860s onward. At that time, the first specimens were probably imported from Japan and exhibited in the zoos of London, Antwerp, and The Hague. Because the bird reached Europe via trading posts in Asia, the English gave it the name “Bengalese finch”, probably because many Asian imports at the time passed through export routes around the Bay of Bengal.
August F. Wiener devotes a paragraph to the Japanese Society Finch in his book The Illustrated Book of Canaries and Cage Birds. August F. Wiener was a prominent nineteenth-century ornithologist, bird expert, and businessman based in London. He himself bought his first white Japanese Society Finches from a London dealer in 1869 or 1870 [4].
I provide here a translation of a passage from his book:
……The Zoological Society appears to have purchased two specimens of the white Japanese variety of Munia striata in October 1860. I do not remember seeing a white Bengalese before 1869 or 1870, when I bought, from a London dealer, the first bird of this kind that I had ever seen. In 1871 a number of white and pied Bengalese were offered to amateurs by the Antwerp Zoo, and since that time these birds have been offered for sale in ever-increasing numbers, so that lately they are rarely absent from a well-stocked bird shop. ….. [5, p. 385].
In other words, one can say that the rise of the Japanese Society Finch in aviculture began quite quickly. And precisely because of that, taxonomic confusion arose. Because biologists at the time thought it was a completely separate bird discovered in the wild in Asia, it was given a full species name in the registers.
In nineteenth-century ornithological lists and museum catalogues it was entered, among other names, as Munia domestica or Uroloncha domestica. Only at the end of the nineteenth century and the beginning of the twentieth century did science come to understand more clearly that this was not a separate natural species, but a human-bred variant. From that point on, its species status in the lists was downgraded to a variety, and it appeared as Uroloncha striata var. domestica, Munia domestica, or Lonchura domestica (a completely separate, human-created species).
China or Japan?
Today it is assumed that the domestication of the Japanese Society Finch, and the adaptations associated with it, began centuries ago in China. There, wild White-rumped Munias were captured and bred for generations because of their song and mutations, such as white patches. Around the eighteenth century, these birds are thought to have been brought to Japan, where breeders perfected selective breeding. As a result, the bird changed so strongly in appearance (pied and white varieties) and behaviour (extremely tame and social) that it became a culture bird in its own right.
The main historical source for this is a 1922 essay by the Japanese prince Nobusuke Takatsukasa (1889–1959). Using an old Japanese bird book, he describes how the first Japanese Society Finches arrived in Japan from China at the beginning of the eighteenth century. Although Japan maintained a strict isolation policy at the time, Chinese merchants were nevertheless able to import goods and live birds via the island of Dejima in Nagasaki. Modern studies confirm this and point to documents showing the import of j?shimatsu from China in 1717, 1762, and 1816 [4].
Once in Japan, the bird was bred intensively, leading to several colour mutations. Because white symbolises purity in Japan, breeders focused specifically on this colour; pied variants were initially regarded merely as a by-product. Unlike the Chinese, the Japanese proved to be true masters of bird breeding, succeeding in multiplying the birds in large numbers in remarkably small cages.
1943. Lonchura striata
During the nineteenth and twentieth centuries, taxonomists abandoned the old, overly broad genus Loxia for these particular estrildid finches. Because the bird proved to fit perfectly within the genus Lonchura as described by Sykes, it was moved there. Under the universal rules of zoological nomenclature, however, the very first valid species name (striata from Linnaeus) must always be retained. From that point onward, the name became Lonchura striata.
The genus Lonchura was established by the English naturalist and military officer William Henry Sykes (1790–1872) in 1832. He introduced the name in a scientific report for the Zoological Society of London, after having studied the natural history of India for many years. Like Cabanis, he chose a name referring to the shape of the tail: Lonchura is a combination of the Ancient Greek words lonkh? (spear point/lance) and oura (tail).
The British naturalist William Henry Sykes had already introduced the genus Lonchura in 1832 for a group of finch-like birds. Nevertheless, it took until well into the twentieth century before scientists decided to abandon the genus Uroloncha. Only then was the White-rumped Munia officially moved to Sykes’s group, giving it its definitive name: Lonchura striata. The French ornithologist Jean Delacour was one of the first to record this officially in a scientific article in 1943 [6]. Because Lonchura (1832) had been described earlier than Uroloncha (1851), that name had “priority” under the rules of taxonomy.
Correct name
Because the Japanese Society Finch looked very different from the wild bird, some biologists long believed that it was a hybrid between several species, or even a completely new species. As a result, it was mistakenly registered in some taxonomic lists as a unique species under the names Uroloncha domestica or Lonchura domestica. In retrospect, this was an error, because under the modern rules of the ICZN (the International Commission on Zoological Nomenclature), a domesticated animal cannot claim its own species name when the wild ancestor is known.
But the discussion continued: is it a combination of several estrildid finches? Or a separate species? Or simply a domesticated form of the White-rumped Munia? Fortunately, science provided an answer to this question.
2021. Chia-Wei Lu, Cheng?te Yao & Chih?Ming Hung
The results of this study appeared in Molecular Ecology, a leading scientific journal in evolutionary biology and genetics. Taiwanese researchers used whole-genome sequencing to map the genome of the Japanese Society Finch and that of its wild ancestor, the White-rumped Munia. The article provides definitive DNA evidence that the Japanese Society Finch is not a hybrid of different finches. It descends purely from the White-rumped Munia through strong selective breeding and inbreeding. The researchers suspect that this domestication began about 250 years ago. This article is therefore the direct source both for correcting genetic computer models and for the hard evidence that the Japanese Society Finch is a product of pure domestication [7].
2024. The Vertebrate Genomes Project (VGP)
This project was officially launched in February 2017. It grew out of the older Genome 10K (G10K) consortium, which had already been established around 2009, but which, thanks to technological advances in DNA sequencing, was relaunched in 2017 as the far more ambitious VGP. This large-scale international scientific initiative aims to accurately map the genetic material (the genome) of all more than 70,000 living vertebrate species on Earth. It is therefore an international collaboration in which dozens of institutes around the world are now represented.
The Japanese Society Finch has also been included in this prestigious project. Scientists, including researchers from Rockefeller University, completed a chromosome-level assembly for it under the code name bLonStr1.mat. This highly accurate DNA profile leaves no doubt: the bird is genetically so identical to Lonchura striata that it is now officially registered in international genetic databases as the domesticated subspecies Lonchura striata domestica. The old theory that it was a hybrid mixture of several species has therefore once again been refuted. The Japanese Society Finch did not arise from a cross between different finch species, as bird breeders often thought, but descends purely from the White-rumped Munia through intensive inbreeding and selective breeding.
2026. Recent contributions
The list of studies concluding that the Japanese Society Finch is the domesticated form of the White-rumped Munia was expanded even further in 2026 by two additional studies. Both are explicit: the Japanese Society Finch is the product of selective breeding from the White-rumped Munia [8], [9].
Lonchura striata domestica
We now regularly see authors refer to the Japanese Society Finch as Lonchura striata var. domestica or Lonchura striata [var. domestica], but the scientifically correct name is Lonchura striata domestica. We must not forget that zoology, and therefore ornithology as well, has strict rules for naming. These are determined by the ICZN (International Code of Zoological Nomenclature).
One of those rules concerns “trinomial nomenclature,” that is, species names consisting of three parts. For animals below species level, such as subspecies, science uses a three-part name: genus, species, subspecies. In other words, below the species level the ICZN recognizes only one official rank: the subspecies. In this case, therefore: Lonchura striata domestica.
The addition “var.” (varietas) is indeed an official taxonomic rank, but only in botany. Moreover, in modern zoology this type of addition has not been used for official scientific names for decades. Under the ICZN guidelines, names published after 1960 with the addition “var.” or “f.” (forma) are considered infrasubspecific, meaning below the level of a subspecies. They therefore have no official taxonomic status.
What would still be possible is Lonchura striata (forma domestica). In that case, the basic species is used, with an informal addition in parentheses to indicate that it concerns the domesticated form.
To conclude
The journey of the Japanese Society Finch — from the historical confusion surrounding the “kernel-breaker” from Réunion to the fully mapped reference genome within the prestigious Vertebrate Genomes Project — shows just how remarkable this bird is. What once began as careful selection by Chinese and Japanese breeders has led to a unique culture bird. Thanks to modern DNA research, we now know with complete certainty what we are dealing with biologically: not a mysterious hybrid, but Lonchura striata domestica.
For the enthusiast, little changes in practice: it remains the same familiar, social, and fascinating cage bird. At the same time, the Japanese Society Finch is also a valuable model for understanding evolutionary biology and domestication. It proves once again that behind an apparently ordinary creature there may be a fascinating piece of natural history hidden.
Dirk
Sources
[1] H. Masatomi, “Communal Use of One and the Same Nest by Two Breeding Pairs of the Bengalee,” Behaviour, vol. 17, no. 4, pp. 261–274, 1961.
[2] B. I. (BirdLife International), “IUCN Red List of Threatened Species: Lonchura striata,” IUCN Red List Threat. Species, Jun. 2024, Accessed: May 18, 2026. [Online]. Available: https://www.iucnredlist.org/en
[3] A. Birembaut, “Les liens de famille entre Réaumur et Brisson, son dernier élève,” Rev. Hist. Sci., vol. 11, no. 2, pp. 167–169, 1958, doi: 10.3406/rhs.1958.4400.
[4] I. Svanberg, “Towards a cultural history of the Bengalese Finch (Lonchura domestica),” Zool. Gart., vol. 77, no. 5, pp. 334–344, Jul. 2008, doi: 10.1016/j.zoolgart.2008.05.003.
[5] W. A. Blakston, W. A. Blakston, W. Swaysland, and A. F. Wiener, The illustrated book of canaries and cage-birds, British and foreign. London: Cassell, Petter, Galpin & Co, 1878. doi: 10.5962/bhl.title.46866.
[6] J. Delacour, “A revision of the subfamily Estrildinae of the family Ploceidae,” Zool. Sci. Contrib. N. Y. Zool. Soc., vol. 28, no. 11, pp. 69–86, Sep. 1943, doi: 10.5962/p.184665.
[7] C. Lu, C. Yao, and C. Hung, “Domestication obscures genomic estimates of population history,” Mol. Ecol., vol. 31, no. 3, pp. 752–766, Feb. 2022, doi: 10.1111/mec.16277.
[8] K. Suzuki and K. Okanoya, “Domestication Effects on Immune Response: Comparison of Phytohemagglutinin-Induced Skin Swelling in Domesticated Bengalese Finch and Its Wild Ancestor, White-Rumped Munia,” J. Exp. Zool. Part Ecol. Integr. Physiol., vol. n/a, no. n/a, doi: 10.1002/jez.70087.
[9] M. Farias-Virgens, D. Peede, T. Deacon, K. Okanoya, S. A. White, and E. Huerta-Sanchez, “To Tame a Songbird: The Genomics of the Domestication Syndrome in a Songbird Model Species,” Res. Sq., p. rs.3.rs-4921127, Apr. 2025, doi: 10.21203/rs.3.rs-4921127/v1.