The common myna or Indian myna ( Acridotheres tristis), sometimes spelled mynah, is a bird in the family Sturnidae, native to Asia. An omnivorous open woodland bird with a strong territorial instinct, the common myna has adapted extremely well to Urban area environments.
The range of the common myna is increasing at such a rapid rate that in 2000 the IUCN Species Survival Commission declared it one of the world's most invasive species and one of only three birds listed among "100 of the World's Worst Invasive Species" that pose a threat to biodiversity, agriculture and human interests. In particular, the species poses a serious threat to the of Australia, where it was named "The Most Important Pest/Problem" in 2008.
When the Swedish naturalist, Carl Linnaeus, updated his Systema Naturae in 1766, for the 12th edition, he added 240 species that had been previously described by Brisson. One of them was the common myna. Linnaeus included a brief description, coined the binomial name Paradisea tristis and cited Brisson's work. The type location was subsequently corrected to Pondicherry in southern India. The specific name tristis is Latin for "sad" or "gloomy". This species is now placed in the genus Acridotheres that was introduced by the French ornithologist Louis Pierre Vieillot in 1816. The generic name Acridotheres is from the Greek language ακριδος ( akridos), meaning locust, and θηρας ( theras), meaning hunter.
Two subspecies are recognised:
, Sri Lanka]]The common myna has been introduced to many other parts of the world such as Canada, Australia, Turkey, Israel, New Zealand, New Caledonia, Fiji, the United States (South Florida only), South Africa, Kazakhstan, Kyrgyzstan, Uzbekistan, Cayman Islands, Islands in the Indian Ocean (the Seychelles – from which it was subsequently eradicated at great expense, Mauritius, Réunion, Madagascar, the Maldives, the Andaman and Nicobar Islands and the Lakshadweep archipelago) and also in islands of the Atlantic Ocean (such as Ascension Island and Saint Helena), Pacific Ocean and Cyprus, as of February 2022. The range of the common myna is increasing to the extent that in 2000 the IUCN Species Survival Commission declared it among 100 of the world's worst invasive species.
It is typically found in open woodland, cultivation and around habitation. Although it is an adaptable species, its population is abnormal and very much considered a pest in Singapore (where it is locally called as gembala kerbau, literally 'buffalo shepherd') due to competition with the related introduced Javan myna.
The common myna thrives in urban and suburban environments; in Canberra, for instance, 110 common mynas were released between 1968 and 1971. By 1991, common myna population density in Canberra averaged 15 birds per square kilometer. Only three years later, a second study found an average population density of 75 birds per square kilometer in the same area.
The bird likely owes its success in the urban and suburban settings of Sydney and Canberra to its origins; having evolved in the open of India, the common myna is pre-adapted to habitats with tall vertical structures and little to no vegetative ground cover, features characteristic of city streets and urban nature preserves.
The common myna (along with , , and feral ) is a nuisance to city buildings; its nests block gutters and drainpipes, causing water damage to building exteriors.
The normal clutch size is 4–6 eggs. The average size of the egg is . The incubation period is 17 to 18 days and fledging period is 22 to 24 days. The Asian koel is sometimes brood parasitism on this species. Nesting material used by common mynas includes twigs, roots, tow and rubbish. Common mynas have been known to use tissue paper, tin foil and sloughed off snake-skin.
During the breeding season, the daytime activity-time budget of the common myna in Pune in April to June 1978 has been recorded to comprise the following: nesting activity (42%), scanning the environment (28%), locomotion (12%), feeding (4%), vocalisation (7%) and preening-related activities, interactions and other activities (7%).
The common myna uses the nests of woodpeckers, parakeets, etc. and easily takes to nest boxes; it has been recorded evicting the chicks of previously nesting pairs by holding them in the beak and later sometimes not even using the emptied nest boxes. This aggressive behaviour contributes to its success as an invasive species.
There is also some evidence that shows that in introduced environments, the species chooses to nest in more modified and artificial structures than in natural tree cavities when compared to native species.
The function of communal roosting is to synchronise various social activities, avoid predators, exchange information about food sources.
Communal displays (pre-roosting and post-roosting) consist of aerial maneuvers which are exhibited in the pre-breeding season (November to March). It is assumed that this behaviour is related to pair formation.
The common myna is regarded as a pest in South Africa, North America, the Middle East, Australia, New Zealand and many Pacific islands. It is particularly problematic in Australia. Several methods have been tried to control the bird's numbers and protect native species.
The common myna was first introduced to Australia between 1863 and 1872, in Victoria, to control insects in the market gardens of Melbourne. At about the same time, the bird is likely to have spread to New South Wales, where it is currently most populous, but documentation is uncertain. The bird was later introduced to Queensland as a predator of and . Common myna populations in Australia are now concentrated along the eastern coast around Sydney and its surrounding suburbs, with sparser populations in Victoria and a few isolated communities in Queensland. During 2009, several municipal councils in New South Wales began trials of catching myna birds in an effort to reduce numbers.
The myna can live and breed in a wide range of temperatures, ranging from the frosty winters of Canberra to the tropical climate of Cairns. Self-sustaining populations have been found in regions with a mean monthly highest temperature no less than and a mean monthly lowest temperature no less than , implying that the common myna could spread from Sydney northwards along the eastern coast to Cairns, and westwards along the southern coast to Adelaide, but not to Tasmania, Darwin, or the arid outback regions.
Morphological studies show that the process of spatial sorting is at work on the range expansion of A. tristis in South Africa. Dispersal-relevant traits are significantly correlated with distance from the range core, with strong sexual dimorphism, indicative of sex-biased dispersal. Morphological variations are significant in wing and head traits of females, suggesting females as the primary dispersing sex. In contrast, traits not related to dispersal such as those associated with foraging show no signs of spatial sorting but are significantly affected by environmental variables such as vegetation and intensity of urbanisation. To study the invasion genetics and landscape-scale dynamics of A. tristis in South Africa, scientists have recently developed 16 polymorphic nuclear microsatellite markers using the next generation sequencing (NGS) approach.
This aggressiveness has enabled the common myna to displace many breeding pairs of native hollow-nesters, thereby reducing their reproductive success. In Australia, their aggressiveness has enabled them to chase native birds as large as out of their nests.
The common myna is also known to maintain up to two roosts simultaneously; a temporary summer roost close to a breeding site (where the entire local male community sleeps during the summer, the period of highest aggression), and a permanent all-year roost where the female broods and incubates overnight. Both male and female common mynas will fiercely protect both roosts at all times, leading to further exclusion of native birds.
In Hawaii, where the common myna was introduced to control pest armyworms and in sugarcane crops, the bird has helped to spread the robust Lantana camara weed across the islands' open . It also has been recorded as the fourth-ranking avian pest in the fruit industry by a 2004 survey of the Hawaiian Farm Bureau and the sixth in number of complaints of avian pests overall.
Common mynas can cause considerable damage to ripening fruit, particularly grapes, but also figs, apples, pears, strawberries, blueberries, guava, mangoes and breadfruit. Cereal crops such as maize, wheat and rice are susceptible where they occur near urban areas. Roosting and nesting commensal with humans create aesthetic and health concerns. Common mynas are known to carry avian malaria and exotic parasites such as the Ornithonyssus bursia mite, which can cause dermatitis in humans. The common myna can help spread agricultural weeds: for example, it spreads the seeds of Lantana camara, which has been classed as a Weed of National Significance because of its invasiveness. Common mynas are regularly observed to usurp nests and hollows, destroy the eggs and kill the young of native bird species, including seabirds and parrots. There is evidence that common mynas have killed small land
mammals such as mice, squirrels and possums, but further research on these occurrences is under consideration.
The bird called śārikā ( or शारिका) most often refers to the common myna, though there are other candidates.
The Sri Lankan subspecies melanosternus is darker than the Indian subspecies tristis and has half-black and half-white primary coverts and a larger yellow cheek-patch.
Description
Vocalization
Morphometry
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! Parameter/sex!! Male!!Female 120–138 138–147 25–28 35–41 79–96
Distribution and habitat
Behaviour
Breeding
Food and feeding
Roosting behaviour
Invasive species
Australia
Europe
New Zealand
South Africa
The United States
Israel
Effect on ecosystems and humans
Threat to native birds
Threat to crops and pasture
Control
In culture
Gallery
Explanatory notes
Citations
Sources
Further reading
External links
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