A Myna Threat

Overhead many Pacific Islanders may sight a bird that recently was given a ranking amongst the International Conservation Union's top 100 worst environmental invaders. This dubious honor goes to the Myna Bird (acridotheres tristis).

Originally from Southern Asia (particularly in Afghanistan, Sri Lanka and India) where they thrive, mynas were first introduced into Fiji during the late 19th Century and early 20th Century to control insect pests within the growing sugar industry. Later as their reputation as pest controller increased, they were introduced further north to Samoa, American Samoa, French Polynesia, Cook Islands, Hawaii, New Caledonia, Solomon Islands, Wallis and Futuna, Tonga and Vanuatu. Their arrival in Kiribati was more opportunistic, having hitchhiked onboard an inter-island ferry from Fiji.

Although the initial reasons for the birds becoming part of the landscape may have been practical, they are now widely perceived as a pest that has out stayed its welcome. Those advocating the reduction in bird numbers maintain that mynas pose a threat on several fronts.

"There are several kinds of mynas here in the region. If you equated them to a human personality we are talking about an intelligent, confident, competitive type not averse to using aggression to get its way," says Liz Dovey, who runs the Avifauna programme for the South Pacific Regional Environment Programme (SPREP) based in Samoa.

Currently the Pacific region hosts 24 percent of the world's threatened birds, yet its land area is only 0.4 per cent of the globe. Almost all of the birds that have become extinct since the 1800s have been island species, and many of these were in the Pacific.

Some experts believe the mynas' aggressiveness toward indigenous birds has been affecting their numbers and chances of survival. Master scavengers, mynas are able to feed off almost anything, including insects, fruits and vegetables, scraps, pets' food, eggs and even fledgling native birds. However, it is when they compete for nesting sites that they are most disruptive.

Photo: K.W. Bridges

Showing no preference for size or shape of hollows, be they in houses or trees, mynas will build huge nests, which many native birds dislike, and also construct fake nests in adjacent hollows to help protect a breeding territory. While prone to fight amongst themselves particularly during mating season, they will often join forces to drive other birds and mammals out of their dwellings.

Although mynas do not breed rapidly, records of tagged birds in New Zealand show a life span of up to 12 years. Colonies are established in urban centres, or in other places where there is plenty of food, and from there, surplus animals invade the surrounding countryside to the detriment of the native fauna.

The end result is the displacement of native birds living in residential, garden and plantation areas -and this is occurring throughout the region with little sign of abating.

There are instances of mynas swooping down on people. In the Cook Islands, where they have been for nearly 80 years, few other species can now be seen around lowland areas.

An Australian politician, Warren Entsch, says far North Queensland is under attack from what he describes as a "spreading plague." "Not only are (mynas) capable of wiping out most of our native bird species, they are a major threat - through parasites and disease - to many of our native mammal species which nest in tree hollows," he told local media.

With total eradication only a remote possibility, containment is the most viable option. Australian tests have shown good results using traps and humane euthanasia systems. These are now being tested in several Pacific island countries.

Containing the threat posed by this clever yet abrasive bird to our native species and habitat will need more regional cooperation to succeed.

"We need to collect, manage and share information and experiences better," says Dovey. "Through networking, Pacific island countries and territories will be able to access and share the technical help, resources and information they need to best manage invasive species of bird life."

The writer is director of the South Pacific Regional Environment Programme, which is based in Apia, Samoa. See www.sprep.org.ws