Common hill myna

Description

This is a stocky jet-black myna, with bright orange-yellow patches of naked skin and fleshy wattles on the side of its head and nape. At about 29 cm length, it is somewhat larger than the common myna (Acridotheres tristis).

It is overall green-glossed black plumage, purple-tinged on the head and neck. Its large, white wing patches are obvious in flight, but mostly covered when the bird is sitting. The bill and strong legs are bright yellow, and there are yellow wattles on the nape and under the eye. These differ conspicuously in shape from the naked eye-patch of the common myna and bank myna (A. ginginianus), and more subtly vary between the different hill mynas from South Asia: in the common hill myna, they extend from the eye to the nape, where they join, while the Sri Lanka hill myna has a single wattle across the nape and extending a bit towards the eyes. In the southern hill myna, the wattles are separate and curve towards the top of the head. The Nias myna differs in details of the facial wattles, and size, particularly that of the bill.

Sexes are similar; juveniles have a duller bill. The subspecies differ in size, in the pattern of wattles on the head and in the glossiness of the plumage.

A 2020 study found that the subspecies G. religiosa miotera likely represents a distinct species and was likely driven to extinction in the wild in the late 2010s due unsustainable collecting for the wildlife trade. The paper recommends rescuing the last genetically pure captive individuals for the purpose of captive breeding. The International Ornithological Congress tentatively recognises it as a subspecies.

Vocalisations

The common hill myna is often detected by its loud, shrill, descending whistles followed by other calls. It is most vocal at dawn and dusk, when it is found in small groups in forest clearings high in the canopy.

Both sexes can produce an extraordinarily wide range of loud calls – whistles, wails, screeches, and gurgles, sometimes melodious and often very human-like in quality. Each individual has a repertoire of three to 13 such call types, which may be shared with some near neighbours of the same sex, being learned when young. Dialects change rapidly with distance, such that birds living more than 15 km apart have no call-types in common with one another.

Unlike some other birds, such as the greater racket-tailed drongo (Dicrurus paradiseus), the common hill myna does not imitate other birds in the wild, although it is a widely held misconception that they do. On the other hand, in captivity, they are among the most renowned mimics, the only bird, perhaps, on par with the grey parrot (Psittacus erithacus). They can learn to reproduce many everyday sounds, particularly the human voice, and even whistled tunes, with astonishing accuracy and clarity.

Distribution and ecology

This myna is a resident breeder from Kumaon division in India (80° E longitude) east through Nepal, Sikkim, Bhutan and Arunachal Pradesh, the lower Himalayas, terai and foothills up to 2,000 m ASL. Its range continues east through Southeast Asia northeastwards to southern China, and via Thailand southeastwards across northern Indonesia to Palawan in the Philippines. It is virtually extinct in Bangladesh due to habitat destruction and overexploitation for the pet trade. A feral population on Christmas Island has likewise disappeared. Introduced populations exist in Saint Helena, Puerto Rico and perhaps in the mainland United States and possibly elsewhere; feral birds require at least a warm subtropical climate to persist.

This myna is almost entirely arboreal, moving in large, noisy groups of half a dozen or so, in tree-tops at the edge of the forest. It hops sideways along the branch, unlike the characteristic jaunty walk of other mynas. Like most starlings, the hill myna is fairly omnivorous, eating fruit, nectar and insects.

They build a nest in a tree hole. The usual clutch consists of two or three eggs. There is no sexual dimorphism, which limits the selection of potential mates.

Pet trade and conservation

The hill mynas are popular cage birds, well known for their ability to imitate speech. The widely distributed common hill myna is the one most frequently seen in aviculture. Unlike other domesticated birds kept as pets, the mynas are often caught from the wild and sold via traders.

The species is quite common throughout its wide geographical range, with a rapid generation time. On a worldwide scale, the IUCN thus considers the common hill myna of Least Concern. But in the 1990s, nearly 20,000 wild-caught birds were brought into the pet trade each year. In the central part of its range, G. r. intermedia populations have declined markedly, especially in Thailand, which supplied much of the thriving market. On the other hand, neighboring countries met burgeoning domestic demands due to political and socio-economic restrictions on exports. Demand for pet mynas continues to be high in Southeast Asia.

In 1992, Thailand had the common hill myna put on CITES Appendix III, to safeguard its population. In 1997, at the request of the Netherlands and the Philippines, the species was pushed higher to CITES Appendix II. The Andaman and Nicobar Islands subspecies G. r. andamanensis and (if valid) G. r. halibrecta, described as "exceedingly common" in 1874, qualified as Near Threatened in 1991. The former is no longer ubiquitous in the Nicobar Islands and the latter has a very limited range.

Elsewhere, such as in the Philippines and Laos, the decline has been more localized. It is also becoming increasingly rare in the regions of northeastern India due to capture of fledged birds for the illegal pet trade. In the Garo Hills region, locals make artificial nests of a split-bamboo framework covered with grass, and put them up in accessible locations. This protects the mynas from habitat destruction while also controlling the local population. In recent years however, there has been a spike in demand for pet mynas in India despite it being illegal.