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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 native to tropical Asia. Its habitat extends from India and Sri Lanka east to Indonesia and the Philippines. It has been introduced into many other parts of the world and populations have been established in Puerto Rico and Hispaniola as well as parts of Australia and the United States of America. They are found in open habitats, including gardens and agricultural fields where they forage in groups for grass seeds.

Description
The Scaly-breasted Munia is 11–12 cm long. The adult has a stubby dark bill, brown upperparts and a dark brown head. The underparts are white with black 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 immatures of other munias such as the Tricoloured Munia.

Populations within their wide distribution range show variations in plumage color and size, and about 11 subspecies are recognized. These include the nominate form found in the plains of South Asia, including Pakistan, India, Nepal, Bangladesh and Sri Lanka. The name lineoventer was formerly used for the Indian population. Other populations include subundulata from the eastern Himalayas, yunnanensis of southern China, topela of Thailand, cabanisi of the Philippines and fretensis of Singapor and Sumatra. Island populations include nisoria (Java, Bali, Lombok, Sumbawa), particeps (Sulawesi), baweana (Bawean Island), sumbae (Sumba) and blasii (Flores, Timor and Tanimbar).

Along with other Estrildines, these species are thought to have originated in Asia.

Habitat and distribution
Scaly-breasted Munias are found in a range of habitas 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 are some times present at an altitude of 2500 m, and in the Nilgiris, where they are found in summer up to 2100 m. In Pakistan they are restricted to a narrow region from Swat in the west to Lahore avoiding the desert zone and occurring again in India east of a line between Ludhiana and Mount Abu. It is rare in Kashmir.

Outside their native range, escaped birds frequently establish themselves in areas with suitable climate. Escaped or introduced populations have been recorded in the West Indies (Puerto Rico since 1971 ), Hawaii, Australia, Japan and southern United States mainly in Florida and California. In Oahu, Hawaii, they compete for habitats with Lonchura malacca and tend to be rare where the latter is present.

Sociality
Scaly-breasted Munia are known to form large flocks, with as many as 100 birds. Individuals communicated with calls that include a short whistle, variations on kitty-kitty-kitty and a sharp chipping alarm note. They sometimes flick their tails and wings while hopping about. The tail may be flicked laterally, while occasionally they are flicked vertically as well. The tail flicking motion has probably been derived in the course of evolution from some locomotory intention movement. Its present simplified and exaggerated form indicates that the original movement has undergone some ritualization. As a social signal, it gives the intention of moving and helps keep the flock together. When roosting, they sit side-by-side in close contact with each other, with the outmost bird rarely content to remain at this position and will constantly wedge itself into the center. Birds in a flock will sometimes preen each other. The soliciting bird usually shows its chin. Allopreening is usually limited to the face and neck. The flocking drive is more than the drive of sleeping together, feeding together, and preening each other since even just after satisfying these activities, the birds still make vigorous attempts to stay together.

Hostile behavior in Scaly-breasted Munia is rare compared to many other birds. The Scaly-breasted Munia exhibits unritualized intention movements and ambivalent postures, which is not due to relative weakness of hostility since they quarrel frequently, energetically, and at length. Instead, the distinctive feature of the Scaly-breasted Munia is probably correlated with its gregarious nature. The strong tendency of these birds to keep together most of the time obviates the need for hostile patterns.

Food and foraging
The Scaly-breasted Munia feeds mainly on seeds but also eats small berries of Lantana and other plants. Like some other Munias, they also sometimes feed on algae.

The ease of maintaining these birds in captivity has made them popular for studying behavior and physiology. Feeding behavior can be predicted by the optimal foraging theory, where animals minimize costs and maximize food intake when foraging. This theory accounts for the strategies that Scaly-breasted Munia adopt to increase feeding efficacy.

Flock size tradeoffs
Studies on foraging have examined the effect of group size on the goals to reduce time spent on predator vigilance and to increase feeding efficiency. Time spent on vigilance is greatest among solitary individuals and reduces as the group size increases to about four. The “many-eyes” hypothesis predicts a reduction in vigilance levels in larger groups that can cause higher feeding rates if the time that is saved is used for foraging. The birds also collected seeds more quickly in larger groups, which reflects a decrease in vigilance in larger groups, a decrease in handling time, and an increase in both search speed and focus on searching for food. Moreover, advantages of group membership include increased mean food intake rates and reduced variance in foraging success. These foraging advantages rely on the occurrence of joining. Joining is feeding from food discovered or captured by others and results in information sharing and producer-scrounger models. Another aspect of group living is an increase in the competition for resources, which may also contribute to lower antipredatory vigilance due to increased foraging time. Although, other studies show that increased competition results in a decreased feeding rate.

Foraging models
When foraging, Scaly-breasted Munia work together in a group. Group foragers search for their food individually, but in addition they can search for others that have found food and join them. The economic consequences of the decision to join others’ discoveries have been modeled so far in two ways that differ in the degree of compatibility that is assumed between the two search modes: the information sharing and the producer-scrounger models. The behavior patterns of Scaly-breasted Munia have been studied to determine whether they fit the producer-scrounger model or the information sharing model. The information sharing model assumes that individuals can search concurrently for finding and joining opportunities while the producer-scrounger model assumes incompatible search modes. Analysis of covariance shows that the frequencies of hopping with the head pointing up and down were 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 seed distribution, the birds' relative frequency of hopping with the head up changed accordingly. When the seed distribution made use of scrounger tactic that were unprofitable, the frequency of hopping with the head up dropped to zero. Consequently, in the Scaly-breasted Munia, finding and joining behaviour conforms more closely to the assumptions of a producer-scrounger model. Furthermore, studies have shown that Scaly-breasted Munia increase their joining frequency and even their allocation to the scrounger tactic as food was more clumped, lending more support to the applicability of the PS game to ground feeding granivorous birds. Moreover, as group size increases, the foragers increase their use of the scrounger tactic, resulting in increased intervals between patch discoveries and decreased finding rate.

Vigilance
Most social foragers must search for food while avoiding predators. Group-foraging Scaly-breasted Munia engaged in a producer–scrounger game search for their own food by hopping with the head down and search for others' food discoveries by hopping with the head up. It might be suggested that individuals that play scrounger could also, by virtue of their head position, be concurrently 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. However, the scrounger tactic and antipredatory vigilance are two incompatible functions of scanning behaviour based off two findings. The rates of head up recorded in stationary and eating birds increased with increased distance to cover, confirming that the head up behavior functions as antipredatory vigilance. Neither the rates nor the proportion of hops involving scans varied with distance, so scanning while hopping does not contribute to antipredatory vigilance.

Specialized foraging
Scaly-breasted Munias have variable competitive behaviors that allow them to exploit scarce resources. Within this variation there are two foraging alternatives, producers that make the food available and scroungers that steal the food found by the producers, that have been studied extensively with the Scaly-breasted Munia. Studies in which variation occurs in the population even if there is no difference in competitive ability between individuals show that a stable equilibrium can be maintained. When individuals are free to choose between producer and scrounger, a frequency dependent selection results in a stable mixture of producers and scroungers, where each behaviour enjoys the same payoff. Studies have shown that if most of the population were producers, then scroungers would do best because there is plenty of food to steal. On the other hand, if most were scroungers then there would be intense competition for stolen food and a producer would do best.

Three hypotheses might account for consistent foraging specializations across individuals: food source variation, phenotypic differences, and frequency dependent-choice. The food source variation hypothesis predicts that individuals will specialize 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 specialize on the most profitable one. The pattern of specialization 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 specialize on the most profitable skill, but the profitability of each alternative decreases as the number of phenotypically identical foragers gradually specialize on each skill when initially given two equally profitable alternatives. At equilibrium, individual payoffs should be independent of the pattern of specialization. Individuals in flocks of spice finches adjusted their use of the two skills and two birds in each flock specialized on a different skill resulting in a variant of both the food source variation hypothesis and frequency dependent choice hypothesis.

Evolutionarily stable strategies
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) when individuals are free to choose either behaviour. The study used flocks of six birds in an aviary with a partition dividing it into two sections. On the producer side, individuals had access to a string next to the perch, which when pulled released seeds into a dish in the other section. The producer could feed on the seeds by stretching its neck into the other section through a small hole in the partition. Individuals on the scrounger side had no string, so they searched for opportunity created by the producers. The experiment included two situations: scroungers could gain easy access to the seeds by leaving the dish uncovered and only partial access by leaving the dish covered. In the first part situation, birds were unable to move between the two sides of the aviary and the numbers of the flock on the producer and scrounger sides were varied. As predicted, scroungers did better when there were more producers and the predicted equilibrium frequency of scroungers was lower when scroungers found it harder to access the food. In the second situation, all six birds were given free access to both sides of the aviary. The numbers choosing the producers and scrounger strategies converged on the predicted stable frequencies after a few days of testing in each situation. This demonstrated 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 or pick grain 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 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 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 cyptic 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.

Breeding
The breeding season is during the summer rainy season (mainly June to August in India) but can breed at other times. Laboratory studies have found that long day illumination and high humidity trigger gonadal growth. The song of the male is very soft but complex and variable and is 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 slurred whistle. When singing the male sits very erect with the head feathers raised, called the slope posture. There are two types of slope posture, a pre-copulatory one and an ordinary one. The pre-copulatory behavior of Scaly-breasted Munia follow a regular sequence of activities. The first pattern is playing with nest-material and either the male or female can begin this activity. As soon as a bird has satisfactorily arranged the nest material in its bill, it begins to fly around in a zig-zag. Once one bird lands close beside the other, the male bends towards the female and wipe its bill. Then the male begins the pre-copulatory jingle, which differs from an ordinary one in moving its entire body and not just the head. The female then begins tail quivering and the rest of her body remains motionless until mounted.

The nest is a large domed structure made of loose grass, bamboo or other leaves with a side entrance and 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 and Acacia chundra especially short and bushy ones in areas with low canopy cover. The nest opening is located along the most frequent wind direction. In northern India, they preferred isolated Acacia nilotica in non-urban areas but Thuja orientalis and Polyalthia longifolia in urban areas. The clutch is usually 4 to 6 but can be up to 10. Both sexes help build the nest and incubate the eggs. The eggs hatch after about 10 to 16 days.