The scaly-breasted munia or spotted munia (''Lonchura punctulata''), known in the pet trade as nutmeg mannikin or spice finch, is a
sparrow-sized
estrildid finch
Estrildidae, or estrildid finches, is a family (taxonomy), family of small seed-eating passerine birds of the Old World tropics and Australasia. They comprise species commonly known as munias, mannikins, firefinches, parrotfinches and waxbills.
...
native to tropical Asia. A species of the genus ''
Lonchura
''Lonchura'' is a genus of the estrildid finch family, and includes munias (or minias) and mannikins. They are seed-eating birds that are found in South Asia from India, Bangladesh, Sri Lanka east to Indonesia, Papua New Guinea, and the Philippi ...
'', it was formally
described and named by
Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
in 1758. Its name is based on the distinct scale-like feather markings on the breast and belly. The adult is brown above and has a dark conical bill. The species has 11 subspecies across its range, which differ slightly in size and colour.
This
munia
''Lonchura'' is a genus of the estrildid finch family, and includes munias (or minias) and mannikins. They are seed-eating birds that are found in South Asia from India, Bangladesh, Sri Lanka east to Indonesia, Papua New Guinea, and the Philippi ...
eats mainly grass seeds apart from berries and small insects. They
forage
Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...
in flocks and communicate with soft
calls and whistles. The species is highly
social
Social organisms, including human(s), live collectively in interacting populations. This interaction is considered social whether they are aware of it or not, and whether the exchange is voluntary or not.
Etymology
The word "social" derives fro ...
and may sometimes roost with other species of munias. This species is found in tropical
plain
In geography, a plain, commonly known as flatland, is a flat expanse of land that generally does not change much in elevation, and is primarily treeless. Plains occur as lowlands along valleys or at the base of mountains, as coastal plains, and ...
s and
grassland
A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...
s. Breeding pairs construct dome-shaped nests using grass or bamboo leaves.
The species is
endemic
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to Asia and occurs from
India
India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
and
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...
east to
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
and the
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
(where it is called ''mayang pakíng''). It has been introduced into many other parts of the world, and feral populations have established in
Puerto Rico
; abbreviated PR), officially the Commonwealth of Puerto Rico, is a Government of Puerto Rico, self-governing Caribbean Geography of Puerto Rico, archipelago and island organized as an Territories of the United States, unincorporated territo ...
and
Hispaniola
Hispaniola (, also ) is an island between Geography of Cuba, Cuba and Geography of Puerto Rico, Puerto Rico in the Greater Antilles of the Caribbean. Hispaniola is the most populous island in the West Indies, and the second-largest by List of C ...
, as well as parts of Australia, and the United States of America, with sightings in California. The bird is listed as of
least concern
A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
by the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
(IUCN).
Taxonomy
In 1743 the English naturalist
George Edwards included an illustration and a description of the scaly-breasted munia in the first volume of his ''A Natural History of Uncommon Birds''. He used the English name "Gowry Bird". Edwards based his hand-coloured etching on a specimen at the London home of
Charles du Bois,
treasurer
A treasurer is a person responsible for the financial operations of a government, business, or other organization.
Government
The treasury of a country is the department responsible for the country's economy, finance and revenue. The treasure ...
to the
East India Company
The East India Company (EIC) was an English, and later British, joint-stock company that was founded in 1600 and dissolved in 1874. It was formed to Indian Ocean trade, trade in the Indian Ocean region, initially with the East Indies (South A ...
. When in 1758 the Swedish naturalist
Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
updated his ''
Systema Naturae
' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...
'' for the
tenth edition, he placed the scaly-breasted munia with the
crossbill
Crossbills are birds of the genus ''Loxia'' within the finch family (Fringillidae), with six species. These birds are characterized by the mandibles with crossed tips, which gives the group its English name. Adult males tend to be red or orange ...
s in the
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
''
Loxia
Crossbills are birds of the genus ''Loxia'' within the finch family (Fringillidae), with six species. These birds are characterized by the mandibles with crossed tips, which gives the group its English name. Adult males tend to be red or orange ...
''. Linnaeus included a brief description, coined the
binomial name
In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...
''Loxia punctulata'' and cited Edwards' work. Linnaeus specified the
locality
Locality may refer to:
* Locality, a historical named location or place in Canada
* Locality (association), an association of community regeneration organizations in England
* Locality (linguistics)
* Locality (settlement)
* Suburbs and localitie ...
as "Asia" but this was restricted to
Kolkata
Kolkata, also known as Calcutta ( its official name until 2001), is the capital and largest city of the Indian state of West Bengal. It lies on the eastern bank of the Hooghly River, west of the border with Bangladesh. It is the primary ...
(Calcutta) by
E. C. Stuart Baker in 1926. The species is now placed in the
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
''
Lonchura
''Lonchura'' is a genus of the estrildid finch family, and includes munias (or minias) and mannikins. They are seed-eating birds that are found in South Asia from India, Bangladesh, Sri Lanka east to Indonesia, Papua New Guinea, and the Philippi ...
'' that was introduced by the English naturalist
William Henry Sykes
Colonel William Henry Sykes, FRS (25 January 1790 – 16 June 1872) was an English naturalist who served with the British military in India and was specifically known for his work with the Indian Army as a politician, Indologist and ornitholog ...
in 1832.
The genus name ''Lonchura'' combines the Ancient Greek lonkhē meaning "spear-head" or "lance" with oura meaning "tail". The specific epithet is from
Modern Latin
Neo-LatinSidwell, Keith ''Classical Latin-Medieval Latin-Neo Latin'' in ; others, throughout. (also known as New Latin and Modern Latin) is the style of written Latin used in original literary, scholarly, and scientific works, first in Italy d ...
''punctulatus'' meaning "spotted" or "dotted".
Over its large range there are 11 recognised
subspecies
In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...
. These include the
nominate
Nomination is part of the process of selecting a candidate for either election to a public office, or the bestowing of an honor or award. A collection of nominees narrowed from the full list of candidates is a short list.
Political office
In th ...
form found in the plains of the
Indian Subcontinent
The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...
, including Pakistan, India, Iran, Nepal, Bangladesh and Sri Lanka. The name ''lineoventer'' was formerly used for the
India
India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
n population. Other populations include ''subundulata'' from the eastern Himalayas, ''yunnanensis'' of southern China, ''topela'' of Thailand, ''cabanisi'' of the Philippines and ''fretensis'' of Singapore and Sumatra. Island populations include ''nisoria'' (Java, Bali, Lombok, Sumbawa), ''particeps'' (Sulawesi), ''baweana'' (Bawean Island), ''sumbae'' (Sumba) and ''blasii'' (Flores, Timor and Tanimbar).
[
* ''L. p. punctulata'' (]Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
, 1758
Events
January–March
* January 1 – Swedish biologist Carl Linnaeus (Carl von Linné) publishes in Stockholm the first volume (''Animalia'') of the 10th edition of ''Systema Naturae'', the starting point of modern zoologic ...
) – northern Pakistan, India (except northeast), Nepal terai and Sri Lanka
* ''L. p. subundulata'' ( Godwin-Austen, 1874) – Bhutan, Bangladesh, northeast India (Assam) and west Myanmar
* ''L. p. yunnanensis'' Parkes, 1958 – southern China (southeast Xizang
The Tibet Autonomous Region (TAR), often shortened to Tibet in English or Xizang in Hanyu Pinyin, is an autonomous region of the People's Republic of China. It was established in 1965 to replace the Tibet Area, a former administrative divisio ...
, south Sichuan
Sichuan is a province in Southwestern China, occupying the Sichuan Basin and Tibetan Plateau—between the Jinsha River to the west, the Daba Mountains to the north, and the Yunnan–Guizhou Plateau to the south. Its capital city is Cheng ...
, Yunnan
Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...
) and north Myanmar
* ''L. p. topela'' ( R. Swinhoe, 1863) – southern Myanmar, Thailand, southeast China (Taiwan), Hainan Islands, Laos, Cambodia and Vietnam
* ''L. p. cabanisi'' ( Sharpe, 1890) – north and west Philippines (Luzon
Luzon ( , ) is the largest and most populous List of islands in the Philippines, island in the Philippines. Located in the northern portion of the List of islands of the Philippines, Philippine archipelago, it is the economic and political ce ...
, Mindoro
Mindoro is the seventh largest and eighth-most populous island in the Philippines. With a total land area of 10,571 km2 ( 4,082 sq.mi ), it has a population of 1,408,454, as of the 2020 census. It is located off the southwestern coast of ...
, Calauit, Palawan
Palawan (, ), officially the Province of Palawan (; ), is an archipelagic province of the Philippines that is located in the region of Mimaropa. It is the largest province in the country in terms of total area of . The capital and largest c ...
, Panay
Panay is the sixth-largest and fourth-most populous island in the Philippines, with a total land area of and a total population of 4,542,926, as of 2020 census. Panay comprises 4.4 percent of the entire population of the country. The City of Il ...
, Negros
Negros (, , ) is the fourth largest and third most populous island in the Philippines, with a total land area of . The coastal zone of the southern part of Negros is identified as a site of highest marine biodiversity importance in the Coral Tr ...
, Cebu
Cebu ( ; ), officially the Province of Cebu (; ), is a province of the Philippines located in the Central Visayas region, and consists of a main island and 167 surrounding islands and islets. The coastal zone of Cebu is identified as a ...
, Mindanao
Mindanao ( ) is the List of islands of the Philippines, second-largest island in the Philippines, after Luzon, and List of islands by population, seventh-most populous island in the world. Located in the southern region of the archipelago, the ...
) and northern Borneo (coastal west Sabah
Sabah () is a States and federal territories of Malaysia, state of Malaysia located in northern Borneo, in the region of East Malaysia. Sabah has land borders with the Malaysian state of Sarawak to the southwest and Indonesia's North Kalima ...
and Brunei
Brunei, officially Brunei Darussalam, is a country in Southeast Asia, situated on the northern coast of the island of Borneo. Apart from its coastline on the South China Sea, it is completely surrounded by the Malaysian state of Sarawak, with ...
)
* ''L. p. fretensis'' ( Kloss, 1931) – south Malay Peninsula
The Malay Peninsula is located in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The area contains Peninsular Malaysia, Southern Tha ...
, Singapore, Sumatra and Nias Islands
* ''L. p. nisoria'' (Temminck
Coenraad Jacob Temminck (; 31 March 1778 – 30 January 1858) was a Dutch patrician, zoologist and museum director.
Biography
Coenraad Jacob Temminck was born on 31 March 1778 in Amsterdam in the Dutch Republic. From his father, Jacob ...
, 1830) – southern Borneo (western & southern Kalimantan
Kalimantan (; ) is the Indonesian portion of the island of Borneo. It constitutes 73% of the island's area, and consists of the provinces of Central Kalimantan, East Kalimantan, North Kalimantan, South Kalimantan, and West Kalimantan. The non-Ind ...
), Java
Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...
, Bali
Bali (English:; Balinese language, Balinese: ) is a Provinces of Indonesia, province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller o ...
, and western Lesser Sundas
The Lesser Sunda Islands (, , ), now known as Nusa Tenggara Islands (, or "Southeast Islands"), are an archipelago in the Indonesian archipelago. Most of the Lesser Sunda Islands are located within the Wallacea region, except for the Bali pr ...
(Lombok
Lombok, is an island in West Nusa Tenggara province, Indonesia. It forms part of the chain of the Lesser Sunda Islands, with the Lombok Strait separating it from Bali to the west and the Alas Strait between it and Sumbawa to the east. It is rou ...
, Sumbawa
Sumbawa, is an Indonesian island, located in the middle of the Lesser Sunda Islands chain, with Lombok to the west, Flores to the east, and Sumba further to the southeast. Along with Lombok, it forms the province of West Nusa Tenggara, but th ...
)
* ''L. p. sumbae'' Mayr
Mayr is a German surname. Notable people with the surname include:
* Andrea Mayr (born 1979), Austrian female long-distance runner
* Ernst Mayr (1904–2005), German American evolutionary biologist
* Franz Xaver Mayr (1875–1965), Austrian gastro ...
, 1944 – Sumba, in western Lesser Sundas
* ''L. p. blasii'' (Stresemann Stresemann is a German family name which may refer to:
* Christina Stresemann (born 1957), German judge; daughter of Wolfgang Stresemann
* Erwin Stresemann (1889 – 1972), German ornithologist
* Gustav Stresemann
Gustav Ernst Stresemann (; 10 ...
, 1912) – central & eastern Lesser Sundas (Flores
Flores is one of the Lesser Sunda Islands, a group of islands in the eastern half of Indonesia. Administratively, it forms the largest island in the East Nusa Tenggara Province. The area is 14,250 km2. Including Komodo and Rinca islands ...
east to Timor
Timor (, , ) is an island at the southern end of Maritime Southeast Asia, in the north of the Timor Sea. The island is Indonesia–Timor-Leste border, divided between the sovereign states of Timor-Leste in the eastern part and Indonesia in the ...
and Tanimbar Islands
The Tanimbar Islands (; ), also called ''Timur Laut'' (literally, "North East"; ), are a group of about 65 islands in the Maluku province of Indonesia. The largest and most central of the islands is Yamdena; others include Selaru to the sout ...
)
* ''L. p. baweana'' Hoogerwerf, 1963 – Bawean Islands, off northeast Java
* ''L. p. particeps'' (Riley Riley may refer to:
Businesses
* Riley (brand), British sporting goods brand founded in 1878
* Riley Motor, British motorcar and bicycle manufacturera 1890–1969
* Riley Technologies, American auto racing constructor and team, founded by Bob ...
, 1920) – Sulawesi
Sulawesi ( ), also known as Celebes ( ), is an island in Indonesia. One of the four Greater Sunda Islands, and the List of islands by area, world's 11th-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Min ...
The subspecies ''holmesi'' (southeast Borneo) is sometimes recognised.
Description
The scaly-breasted munia is about long and weighs . The adult has a stubby dark bill typical of grain eating birds, brown upperparts and a dark brown head. The underparts are white with dark scale markings. The sexes are similar, although males have darker markings on the underside and a darker throat than females.
Immature birds have pale brown upperparts, lack the dark head found in adults, and have uniform buff underparts that can be confused with juveniles of other munia species such as the tricoloured munia (''Lonchura malacca'') across the Asian and island populations and the black-throated munia (''Lonchura kelaarti'') in parts of India or Sri Lanka.
Distribution and habitat
Scaly-breasted munias are found in a range of habitats but are usually close to water and grassland. In India, they are especially common in paddy fields where they are considered a minor pest on account of their feeding on grain. They are found mainly on the plains, but can be observed in the foothills of the Himalayas, in which they may be present at altitudes near , and in the Nilgiris, where they are found at altitudes up to during the summer. In Pakistan, they are restricted to a narrow region from Swat in the west to Lahore, avoiding the desert zone, and then occurring again in India east of an area between Ludhiana and Mount Abu. The species has also been observed in Kashmir, though this is rare.
Outside their native range, escaped birds frequently establish themselves in areas with a suitable climate and can then colonise new areas nearby. Escaped cagebirds established in the wild and such populations have been recorded in the West Indies (Puerto Rico since 1971), Hawaii (since 1883), Japan and southern United States, mainly in Florida and California. In Oahu, Hawaii, they compete for habitats with the tricoloured munia and tend to be rare where this competitor is present. The species has been introduced to other parts of the world due to its popularity as a cage bird and populations have established in the wild.
Behaviour and ecology
Sociality
Scaly-breasted munias form flocks of as many as 100 birds. Individuals communicate with calls that include a short whistle, variations of ''kitty-kitty-kitty'', and a sharp chipping alarm note. They sometimes flick their tails and wings vertically or horizontally while hopping about. The tail flicking motion may have evolved from a locomotory intention movement. The exaggerated version of the tail flicking movement may have undergone ritualisation. As a social signal, tail flicking in several other species acts as a signal indicating the intent to fly and helps keep flocks together.
When roosting communally, scaly-breasted munia sit side by side in close contact with each other. The outermost bird often jostles towards the center. Birds in a flock sometimes preen each other, with the soliciting bird usually showing its chin. Allopreening
Preening is a found in birds that involves the use of the beak to position feathers, interlock feather that have become separated, clean plumage, and keep ectoparasites in check. Feathers contribute significantly to a bird's insulation, waterp ...
is usually limited to the face and neck. The scaly-breasted munia is rarely hostile but birds will sometimes quarrel without any ritualised posturing.
Breeding
The breeding season is during the summer rainy season (mainly June to August and also in October season in India) but can vary. Laboratory studies have found that long day illumination and high humidity trigger gonadal
A gonad, sex gland, or reproductive gland is a mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, ...
growth. The song of the male is very soft but complex and variable, audible only at close range. This song described as a jingle consists of a series of high notes followed by a croaky rattle and ending in a slurred whistle. When singing the male sits in what is called the ''slope'' posture—erect with the head feathers raised.
There are two types of slope posture, a pre-copulatory one and an ordinary one. The pre-copulatory behaviour of scaly-breasted munia includes a sequence of actions. The first involves either the male or female playing with nest-material. As soon as a bird has arranged the nest material in its bill, it begins to fly around in a zigzag path. Once a bird lands close to its partner, the male bends towards the female and wipes its bill. The male then sings with movements of the body. The female invites mounting with tail quivering. The nest is a large domed structure loosely woven from blades of grass, bamboo or other leaves with a side entrance and is placed in a tree or under the eaves of a house. A study in southern India found the preferred nesting trees to be '' Toddalia asiatica'', ''Gymnosporia montana
''Gymnosporia'' is an Old World genus of plants, that comprise suffrutices, shrubs and trees. It was formerly considered congeneric with ''Maytenus'', but more recent investigations separated it based on the presence of achyblasts (truncated bran ...
'' and '' Acacia chundra'', especially short and bushy ones in areas with low canopy cover. The nest opening is located to face downwind of the most frequent wind direction. In northern India, they preferred isolated ''Acacia nilotica
''Vachellia nilotica'', more commonly known as ''Acacia nilotica'', and by the vernacular names of gum arabic tree, babul, thorn mimosa, Egyptian acacia or thorny acacia, is a flowering tree in the family Fabaceae. It is native to Africa, the M ...
'' in non-urban areas but used '' Thuja orientalis'' and '' Polyalthia longifolia'' in urban gardens.
Scaly-breasted munia clutch
A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...
es usually contain four to six eggs, but can contain up to ten. Both sexes build the nest and incubate the eggs, which hatch in 10 to 16 days.
The species is extensively used as a brood host by the parasitic pin-tailed whydah in Southern California (where both species are feral) with the munia raising the whydah's chicks as its own. This relationship is novel, as the two species do not naturally co-occur in their native ranges, and had no established evolutionary relationship as parasite and host.
Food and foraging
The scaly-breasted munia feeds mainly on grass seeds, small berries such as those of ''Lantana
''Lantana'' () is a genus of about 150 species of perennial plant, perennial flowering plants in the verbena family, Verbenaceae. They are native to tropics, tropical regions of the Americas and Africa but exist as an introduced species in num ...
'', and insects. Although the bill is suited for crushing small grains, they do not show lateral movements of the lower mandible that e.g. greenfinches show, which help in dehusking seeds. Like some other munia
''Lonchura'' is a genus of the estrildid finch family, and includes munias (or minias) and mannikins. They are seed-eating birds that are found in South Asia from India, Bangladesh, Sri Lanka east to Indonesia, Papua New Guinea, and the Philippi ...
s, they may also feed on algae, a rich protein source, prior to the breeding season.
The ease of maintaining these birds in captivity
Captivity, or being held captive, is a state wherein humans or other animals are confined to a particular space and prevented from leaving or moving freely. An example in humans is imprisonment. Prisoners of war are usually held in captivity by a ...
has made them popular for studying behaviour and physiology. Feeding behaviour can be predicted by the optimal foraging theory
Optimal foraging theory (OFT) is a behavioral ecology model that helps predict how an animal behaves when searching for food. Although obtaining food provides the animal with energy, searching for and capturing the food require both energy and ti ...
, where animals minimise time and energy spent to maximise food intake. This theory has been tested by studying the strategies used by scaly-breasted munias to increase their feeding efficacy.
Flock size tradeoffs
Studies on foraging have examined the effect of group size in reducing time spent on predator
Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...
vigilance, thereby increasing feeding efficiency. According to the "many-eyes" hypothesis, a reduction in the individual time spent on vigilance
Vigilance may refer to:
* Alertness
* Vigilance, a creature ability in the ''Magic: The Gathering'' collectible card game
* ''Vigilance'' (album), by Threat Signal
* Vigilance (behavioural ecology), the watchfulness of prey for nearby predator ...
against threats in larger groups allows for more time to be spent on searching for food and feeding. Vigilance is greatest among solitary individuals and reduces as the group size increases to about four. The birds collect seeds more quickly in larger groups, reflecting a decrease in individual vigilance, a decrease in handling time, and an increase in both search speed and focus when foraging.
Individuals may also take advantage of group foraging by "joining" members that have found food. The options to seek food or to join others that have discovered food involves information sharing and has been studied through what are termed "producer-scrounger models". A cost associated with group foraging is increased resource competition, which in turn may reduce anti-predatory vigilance due to the intensity of foraging. Some studies show that increased competition results in a decreased feeding rate.
Foraging models
When foraging, scaly-breasted munia can search as individuals or search for others that have found food and join them. The economic consequences of the decision to join others has been modeled in two ways: the producer-scrounger model and the information sharing model. These models are based on hypotheses that differ in the degree of compatibility that is assumed between the two food and joining opportunity search modes.
The information sharing model assumes that individuals search concurrently for finding and joining opportunities while the producer-scrounger model assumes that the search modes are mutually exclusive. Hopping with the head facing up and downward are observed to be statistically associated with the frequencies of a bird's joining and finding, respectively. When the expected stable frequency of the scrounger tactic was altered by changing the availability of seeds, the relative frequency of hopping with the head up changed accordingly. When the seed distribution made the scrounger tactic unprofitable, the frequency of hopping with the head up diminished and appears to support the predictions of the producer-scrounger model.
Studies show that scaly-breasted munias tend to adopt the scrounger tactic when food is more clumped and when the group size increases. When most foragers adopt scrounging, the time taken to discover new food patches is greater.
Vigilance
Most social foragers must search for food while also avoiding predators. It has been suggested that individuals that play scrounger could also, by virtue of their head position, be alert for predators and hence contribute to antipredatory vigilance. If the scrounger tactic is compatible with antipredatory vigilance, then an increase in antipredatory vigilance should lead to the detection of more joining opportunities, and hence more joining. When stationary, the head-up tactic has been shown to be associated with antipredatory vigilance. However scanning while hopping does not aid in vigilance and it is thought that the scrounger tactic is incompatible with antipredatory vigilance in the scaly-breasted munia.
Specialised foraging
Scaly-breasted munias have variable competitive behaviour that allows them to exploit scarce resources. There are two foraging alternatives: producers that make the food available and scroungers that steal food found by the producers. Studies show that these choices lead to a stable equilibrium within a group. When individuals are free to choose between producer and scrounger, frequency dependent selection
Frequency-dependent selection is an evolutionary process by which the fitness of a phenotype or genotype depends on the phenotype or genotype composition of a given population.
* In positive frequency-dependent selection, the fitness of a phenotyp ...
results in a stable mixture of both behaviour where each receives similar payoff. Studies indicate that if most of the population consists of producers, then scrounging behaviour is favoured by natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generation ...
because there is plenty of food to steal. On the other hand, if most birds exhibit scrounging then the competition for stealing is so great that producing is favoured.
Three hypotheses might account for consistent foraging specialisations across individuals: food source variation, phenotypic
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...
differences, and frequency dependent-choice. The food source variation hypothesis predicts that individuals will specialise when the use of two skills is more costly than specialist foraging. The phenotypic differences hypothesis proposes that individuals differ in their ability to use each foraging skill and stably specialise on the most profitable one. The pattern of specialisation is expected to be stable although the number of individuals that use a given skill depends on the phenotypic composition of the flock. The frequency dependent choice hypothesis also proposes that individuals specialise on the most profitable skill, but the profitability of each alternative decreases as the number of phenotypically identical foragers gradually specialise on each skill when initially given two equally profitable alternatives. At equilibrium, individual payoffs should be independent of the pattern of specialisation. Individuals in flocks adjusted their use of the two skills and two birds in each flock specialised on a different skill resulting in a variant of both the food source variation hypothesis and frequency dependent choice hypothesis.
Aviary experiments conducted with captive flocks of scaly-breasted munia have tested whether producers and scroungers reach the predicted stable equilibrium frequency (see Evolutionarily stable strategy
An evolutionarily stable strategy (ESS) is a strategy (or set of strategies) that is ''impermeable'' when adopted by a population in adaptation to a specific environment, that is to say it cannot be displaced by an alternative strategy (or set of ...
) when individuals are free to choose either behaviour. The numbers choosing either producers and scrounger strategies have been shown to converge on stable frequencies while demonstrating that variation in tactics arise through frequency dependent pay-offs from the choice of different feeding strategies.
Furthermore, foraging birds may feed actively on the substrate
Substrate may refer to:
Physical layers
*Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached
** Substrate (aquatic environment), the earthy material that exi ...
or pick grains dropped on the ground and these strategies may be chosen according to the situation. Early departures occur more often when expected searching time decreases and when competition
Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indi ...
intensity increases. Competition intensity is expected to increase when more scroungers are present or when patches are smaller.
Prey crypsis
Since producers search for food and scroungers wait for opportunities to join, prey crypsis
In ecology, crypsis is the ability of an animal or a plant to avoid observation or detection by other animals. It may be part of a predation strategy or an antipredator adaptation. Methods include camouflage, nocturnality, subterranean life ...
imposes a producer specific cost that shifts the producer scrounger equilibria towards more scrounging. Prey crypsis resulted in increased latency to eat the seed and increased number of detection errors. Moreover, the presence of a competitor negatively affected foraging efficiency under cryptic backgrounds. The foraging efficiency of individuals that had previously foraged with a competitor on cryptic seeds remained low even after the competitor had been removed. Thus, the costs of foraging on cryptic prey may be greater for social foragers than for solitary foragers.
Resource defence
Recent models of economic defence in a group-foraging context predict that the frequency of aggressive interactions should decline as resource density increases. Studies with scaly-breasted munia show that the intensity of aggressive encounters was highest when patch location was signaled, and the effect of changing resource density depended on whether patch location was signaled or not. Signaling patch location was equivalent to making the resources more spatially predictable. Changing patch density had no effect on the number of aggressive encounters when the location of food was not signaled. When food location was signaled, increasing patch density resulted in the predicted decrease in the number of aggressive encounters.
Conservation
The scaly-breasted munia is an abundant species and classified as least concern
A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
on the IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...
. The species occupies an extremely large range, and its population, while still unquantified, is large and stable. The scaly-breasted munia is not globally threatened and is common to very common throughout most of its range. However, some populations are dwindled due to the increase of bird cagings.
In many areas it is regarded as an agricultural pest, feeding in large flocks on cultivated cereal
A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...
s such as rice
Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
. In Southeast Asia, the scaly-breasted munia is trapped in large numbers for Buddhist life release
Life release, also known as merit release, mercy release, fangsheng (from Mandarin Chinese 放生) or prayer animal release, is a Buddhist practise of releasing animals held captive with the presumed intention of saving their lives, if they were ...
rituals. While most birds are eventually released, the post-release mortality rate can be as high as 90%.
References
External links
Pictures, videos and sound
Oriental Bird Images: ''Scaly-breasted Munia''
Selected images
eBird: Scaly-breasted Munia (''Lonchura punctulata)''
{{Taxonbar , from=Q36197
scaly-breasted munia
The scaly-breasted munia or spotted munia (''Lonchura punctulata''), known in the pet trade as nutmeg mannikin or spice finch, is a Old World sparrow, sparrow-sized estrildid finch native to tropical Asia. A species of the genus ''Lonchura'', it ...
Birds of Indomalaya
Birds of Taiwan
Birds of the Dominican Republic