Being very popular, the Common Hill Myna is known to all. This glossy-black myna with yellow wattle on its neck is common in the lowland forests of Sumatra, Kalimantan and its satellite islands, and Nusa Tenggara. Forests on the islands of Java and Bali used to host a large number of this species, but due to poaching and forest destruction, it is now hardly found in nature.
The International Convention on Trade in Endangered Species (CITES) recorded that this species, whose scientific name is Gracula religiosa, has been rampantly traded in large numbers on both domestic and international markets. “A subspecies of Common Hill Myna from Nias region, locally known as beo nias, is considerably desired by Indonesian market,” said Jihad, Bird Conservation Officer of Burung Indonesia.
The Common Hill Myna is popular because it is able to imitate the human voice. The secret lies in the syrinx resembling the human throat. On the wall of the syrinx there is a cartilage protrusion called the external labium, one of which works like the human vocal cords and is responsible for supplying sound-producing energy.
The results are myriad types of calls from whistling, screaming, gurgling to wailing, produced tunefully and often resembling human voice. An individual of Common Hill Myna produces three to thirteen types of call.
What's unique is that each population of Common Hill Myna separated by a distance of 14-15 km has its own distinct calls, meaning within that distance range, the Chinese gold population cannot imitate each other's calls made by their neighbors.
Unlike the Greater Racquet-tailed Drongo (Dicrurus paradiseus), which often imitate other bird’s calls, the Common Hill Myna don’t do it. However, in captivity, Common Hill Mynas have shown extraordinary ability on learning and imitating sounds, in particular, human voices.
“This amazing ability causing many people hunt the Common Hill Myna,” Jihad said. Humans are competing to have this bird for themselves. In addition to habitat destruction that reduces this species population in the wild, catching and hunting for trade to the international market causes the population to decline throughout its range of distribution.