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 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 ecosystems of Australia, where it was named "The Most Important Pest/Problem" in 2008.
Taxonomy In 1760, the French zoologist Mathurin Jacques Brisson included a description of the common myna in his Ornithologie, based on a specimen that he mistakenly believed had been collected in the Philippines. He used the French name Le merle des Philippines and the Latin Merula Philippensis. The two stars (**) at the start of the section indicates that Brisson based his description on the examination of a specimen. Although Brisson coined Latin names, they do not conform to the binomial system and are not recognised by the International Commission on Zoological Nomenclature.
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.
Etymology 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 : , genitive : meaning locust, and : , meaning hunter.
Subspecies Two subspecies are recognised: the Indian myna (A. t. tristis) (Linnaeus, 1766) – It is found from southern Kazakhstan, Turkmenistan and eastern Iran to southern China, Indochina, the Malay Peninsula and southern India. It has also been introduced to Hawai‘i and North America. Populations from the northwest of its range have sometimes been separated as a distinct subspecies, A. t. neumanni, while populations from Nepal and Myanmar have been described as A. t. tristoides. the Sri Lankan myna (A. t. melanosternus) Legge, 1879 – Sri Lanka 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
The common myna is readily identified by the brown body, black hooded head and the bare yellow patch behind the eye. The bill and legs are bright yellow. They have rounded wings as well, and a round square tipped tail. There is a white patch on the outer primaries and the wing lining on the underside is white, as well as having a white tail tip. The sexes are similar in colour and birds are usually seen in pairs. The common myna obeys Gloger's rule in that the birds from northwestern India tend to be paler than their darker counterparts in southern India.
Vocalization The calls includes croaks, squawks, chirps, clicks, whistles and 'growls', and the bird often fluffs its feathers and bobs its head in singing. The common myna screeches warnings to its mate or other birds in cases of predators in proximity or when it is about to take off flying. Common mynas are popular as cage birds for their singing and "speaking" abilities. Before sleeping in communal roosts, common mynas vocalise in unison, which is known as "communal noise".
Characteristics The common myna has clear sexual dimorphism in weight, with males having an average weight of 109.8g, and females weighing from 120g-138g. Despite females on average being heavier, male common mynas are longer than females, with an average weight of 23.82cm compared to a females average length of 22.97cm.
Distribution and habitat
The common myna is native to Asia, with its initial home range spanning Iran, Pakistan, India, Nepal, Bhutan, Bangladesh and Sri Lanka, Afghanistan, Uzbekistan, Tajikistan, Turkmenistan, Myanmar, Malaysia, Singapore, peninsular Thailand, Indochina, Japan (both mainland Japan and the Ryukyu Islands) and China.
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 and Hawaii), South Africa, Kazakhstan, Kyrgyzstan, 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 (such as Ascension 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 evolutionary origins; having evolved in the open woodlands 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 common starlings, house sparrows, and feral rock doves) is a nuisance to city buildings; its nests block gutters and drainpipes, causing water damage to building exteriors.
Behaviour
Breeding
Common mynas are believed to pair for life. They breed through much of the year depending on the location, building their nest in a hole in a tree or wall. They breed at elevations of in the Himalayas.
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 parasitic 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.
Food and feeding Like most starlings, the common myna is omnivorous. It feeds on insects, grubs, earthworms, arachnids, crustaceans, reptiles, small mammals, seeds, grain, fruits, flower nectar and petals, and discarded waste from human habitation. It forages on the ground among grass for insects, and especially for grasshoppers, from which it gets the generic name Acridotheres, "grasshopper hunter". It, however, feeds on a wide range of insects, mostly picked from the ground. It is a cross-pollinator of flowers such as Salmalia and Erythrina. It walks on the ground with occasional hops and is an opportunistic feeder on the insects disturbed by grazing cattle as well as fired grass fields. They prey on eggs and young of other birds, such as Hawaiʻi ʻakepas (Loxops coccineus). They sometimes even wade in shallow waters to catch fish. Living in close proximity to human-made habitats, common mynas may also appear near roadsides to feed on roadkill. Roosting behaviour Common mynas roost communally throughout the year, either in pure or mixed flocks with jungle mynas, rosy starlings, house crows, jungle crows, cattle egrets and rose-ringed parakeets and other birds. The roost population can range from less than one hundred to thousands. The time of arrival of mynas at the roost starts before and ends just after sunset. The mynas depart before sunrise. The time and timespan of arrival and departure, time taken for final settlement at the roost, duration of communal sleep, flock size and population vary seasonally.
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.
Invasive species
The IUCN declared the common myna as one of only three birds among the world's 100 worst invasive speciesLowe S., Browne M., Boudjelas S. and de Poorter M. (2000, updated 2004). 100 of the World's Worst Invasive Alien Species: A selection from the Global Invasive Species Database . The Invasive Species Specialist Group (ISSG), a specialist group of the Species Survival Commission (SSC) of the World Conservation Union (IUCN), Auckland. (the other two being the red-vented bulbul and the common starling). The French introduced it in the 18th century from Pondicherry to Mauritius with the aim of controlling insects, even levying a fine on anyone persecuting the bird. It has since been introduced widely elsewhere, including adjacent areas in Southeast Asia, Madagascar, the Middle East, South Africa, the United States, Argentina, Germany, Spain and Portugal, the United Kingdom, Australia, New Zealand and various oceanic islands in the Indian and Pacific Oceans, including prominent populations in Fiji and Hawaii.Long, John L. (1981). Introduced Birds of the World. Agricultural Protection Board of Western Australia, 21-493
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.
Australia
In Australia, the common myna is an invasive pest. They are often the predominant bird in urban areas along the whole east coast. In a 2008 popular vote, the bird was named "The Most Important Pest/Problem" in Australia. They have earned the nickname "flying rats", due to their numbers and their scavenging behaviour. They are also known as "the cane toad of the sky". However, there is little scientific consensus concerning the extent of its impact on native species.Grarock et al (2013) Are invasive species drivers of native species decline or passengers of habitat modification? A case study of the impact of the common myna (Acridotheres tristis) on Australian bird species. Austral Ecology.