Wikipedia:School and university projects/7th Basic Ornithology Course, Pune/Common Myna

IMPORTANT NOTICE: This is the draft of the Wikipedia article on Common Myna being improved by the 7th Basic Ornithology Course, Pune run by Ela Foundation and Abasaheb Garware College of Arts and Sciences. For more details see this page. -

The Common Myna or Indian Myna (Acridotheres tristis) also sometimes spelled Mynah, is a member of family Sturnidae, (starlings and mynas) native to Asia. An omnivorous open woodland bird with a strong territorial instinct, the Myna has adapted extremely well to urban environments. The myna has been introduced in many other parts of the world and its distribution range is on the increase. It is a serious threat to the ecosystems of Australia. The Common Myna is an important motif in Indian culture and appears both in Sanskrit and Prakrit literature.

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. There is a white patch on the outer primaries and the wing lining on the underside is white. The sexes are similar and birds are usually seen in pairs.

The Common Myna obeys Gloger's rule in that the birds from northwest India tend to be paler than their darker counterparts in South India.

Distribution
It is a species of bird native to Asia with its initial home range spanning from Iran, the entire South Asian subcontinent, including Pakistan, India, Nepal, Bhutan, Bangladesh and Sri Lanka; as well as Turkmenistan, Afghanistan, Kazakhstan, Myanmar, to Malaysia, peninsular Thaland, Indo-China and China.

The Myna has been introduced in many other parts of the world such as Australia, New Zealand, Hawaii, South Africa, and islands in the Indian Ocean (Seychelles, Mauritius, Maldives, Andaman and Nicobar Islands and Lakshadweep archipelago and also in islands of the Atlantic and Pacific Oceans. The distribution range of Common Myna is on the increase to an extent that in 2000 the IUCN Species Survival Commission declared it among the World's 100 worst invasive species. The Myna is one of only three birds in this list of invasive species.

Etymology
The etymology of the scientific name is as follows :
 * Acridotheres : Greek akris, akrodos, a locust; theres, a hunter.
 * tristis : Latin tristis, sad, gloomy; Modern Latin tristis, dull-coloured).

Type locality
The type locality of the nominate race is Pondicherry, (India).

Taxonomy and subspecies
The Common Myna has two subspecies : The subspecies melanosternus is darker than the nominate subspecies, has half-black and half-white primary coverts and has a larger yellow cheek-patch.
 * Acridotheres tristis tristis (Linnaeus, 1758). Widespread, including Sri Lanka.
 * A. t. melanosternus Legge, 1879. Endemic to Sri Lanka.

Morphometry
Morphometry is as per Ali & Ripley (2001).
 * Body length:23 cms.

Vocalisation
The calls includes croaks, squawks, chirps, clicks and whistles, 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 its about to take off flying. Common Mynas are popular as cage birds for their singing and "speaking" abilities. Before sleeping in communal roosts, mynas vocalise in unison which is called as "communal noise".

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 from sea-level to 3000 m in the Himalayas.

The normal clutch size is 4–6 eggs. The average size of the egg is 30.8 x 21.99 mm. The incuation 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 mynas include twigs, roots, tow and rubbish. 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 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 is considered to contribute to its success as an invasive species.

Food and feeding
Like most starlings, the Common Myna is omnivorous. It feeds on insects, arachnids, crustaceans, reptiles, small mammals, seeds, grain and fruits 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.

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) comprise 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.

Habitat
This abundant passerine is typically found in open woodland, cultivation and around habitation.

Although this is an adaptable species, its population has been decreasing significantly in Singapore and Malaysia (locally called as 'gembala kerbau', literally 'buffalo shepherd') due to competition with its cousin, the introduced Javan Myna.

Urban success
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 European 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.

Invasive species
The IUCN declared this myna as one of the only three birds among the world's 100 worst invasive species. (Other two invasive birds being Red-vented bulbul and European Starling) It has been introduced widely elsewhere, including adjacent areas in Southeast Asia, Madagascar, the Middle East, South Africa, Israel, North America, Europe, Australia, New Zealand and various oceanic islands, including a very prominent population in Hawaii.

The Common Myna is 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 now often the predominant bird in urban areas all along the East coast. In a 2008 popular vote, the bird was named "The Most Important Pest/Problem" in Australia, also earning the nickname "flying rats" due to their scavenging resembling that of rats.

The Common Myna was first introduced to Australia in Victoria between 1863 and 1872 into Melbourne’s market gardens to control insects. The bird is likely to have spread to New South Wales (where it is currently most populous) at around the same time, but documentation is uncertain. The bird was later introduced to Queensland as a predator ofgrasshoppers and cane beetles; the reasons for its original introduction to Victoria is however, lost in history. Currently, Common Myna populations in Australia are concentrated along the eastern coast around Sydney and its surrounding suburbs, with sparser populations in Victoria and a few isolated communities in Queensland.

The bird can live and breed in a wide range of temperatures, though it thrives in hotter regions. Self-sustaining populations of Common Myna have been found in regions of mean warmest month temperature no less than 23.2°C and mean coldest month temperature no less than -0.4°C, implying that the Common Myna could potentially spread from Sydney northward along the eastern coast to Cairns and westward along the southern coast to Adelaide (though not toTasmania, Darwin, or across the Great Dividing Range to the arid interior regions).

South Africa
In South Africa where it escaped into the wild in 1902, it has become very common and its distribution is greater where human populations are greater or where there is more human disturbance. The bird is also notorious for being a pest, kicking other birds out of their nests and killing their young due to the Myna's strong territorial instinct, in South Africa it is considered somewhat of a major pest and disturbance of the natural habitat, so they are frequently shot and killed by people in urban environments and farmers alike.

Threat to native birds
The Common Myna is a hollow-nesting species; that is, it nests and breeds in protected hollows found either naturally in trees or artificially on buildings (for example, recessed windowsills or low eaves). Compared to native hollow-nesting species, the Common Myna is extremely aggressive, and breeding males will actively defend areas ranging up to 0.83 hectares in size (though males in densely populated urban settings tend to only defend the area immediately surrounding their nests).

This aggressiveness has enabled the Common Myna to displace many breeding pairs of native hollow-nesters, thereby reducing their reproductive success. In particular, the reproduction rates of native hollow-nesting parrots in thebush land of eastern Australia have been reduced by up to 80% by the Common Myna (which was even able to out-compete another aggressive introduced species in the area, the European Starling).

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.

Threat to crops and pasture
The Common Myna (which feeds mostly on ground-dwelling insects, tropical fruits such as grapes plums and someberries and, in urban areas, discarded human food) poses a serious threat to Australian blueberry crops, though its main threat is to native bird species.

In Hawaii, where the Common Myna was introduced to control pest armyworms and cutworms in sugarcane crops, the bird has helped to spread the robust Lantana camara weed across the islands’ opengrasslands.

In culture
The Common Myna widely appears under the name saarika in Indian culture from Vedic times, featuring both in classical Indian literature (Sanskrit) as well as in Prakrit Buddhist texts. The Sankrit term shuksarika, which refers to the Rose-ringed Parakeet (shuk) and the Common Myna (saarika), is used to indicate a pair or a couple, probably because both birds are vocal and capable of mimicking human sound.

In Sanskrit literature, the Common Myna has a number of names, most are descriptive of the appearance or behaviour of the bird. In addition to saarika, the names for the Common Myna include kalahapriya, which means "one who is fond of arguments" referring to the quarrelsome nature of this bird; chitranetra, meaning "picturesque eyes"; peetanetra (one with yellow eyes) and peetapaad (one with yellow legs).

Books

 * Kannan, R., and D. A. James. 2001. Common Myna (Acridotheres tristis). In The Birds of North America, No. 583 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Theses

 * Tunhikorn S. Ph.D. (1989). Resource partitioning of four sympatric mynas and starlings (Sturnidae) in Thailand. Oregon State University, United States.