The Bali Mynah Story

Arguably, there is only one species of passerine that is managed in captivity as a truly self-sustaining population: the national bird of Bali and the only endemic bird species on that island, the Rothschild's or Bali mynah Leucopsar rothschildi. Also known as a starling or grackle, this critically endangered species was first described and placed in its own genus by Stresemann in 1912. He had discovered it a year earlier while exploring the dry lowland forest along the northwestern coast of Bali, in what was then the Dutch East Islands. Bali is one of over 13,000 islands that make up the SE Asian Republic of Indonesia. It lies in the Indian Ocean, only 8 degrees south of the equator, and is located east of Java and north-west of Australia. Measuring only 140km by 80km (area 5620 sq. km), the island is dominated by a series of towering volcanoes that range its entire width. The tallest is over 3000m. Tropical rainfall, consistent temperatures and the rich volcanic soil, provide an ideal environment for intensive agriculture which includes the production of rice, coffee, copra, and vegetables, as well as cattle herding. Indonesia's climate is hot all of the year (between 32° and 35° C), though cooler in the mountains of islands such as Java, Sumatra and Sulawesi. Monsoons bring two seasons: wet from December to March, and dry for the rest of the year. Some islands have no dry season.

With its natural range being so limited, the wild population of the Bali mynah has always been small. Even the most optimistic observers have never put it at more than 1000 birds. But following its discovery, the numbers have declined at a precipitous rate. In the 1920’s, the Bali mynah occupied 30,000 ha. By the late 1980’s, the range had shrunk to only 4000 ha as the population receded into a small part of the Bali Barat National Park in the northwest of the island (Helvoort,1990). Since 1966, the Bali mynah has been listed as Endangered in the IUCN Red data book. (Helvoort,B.E.van (1990) The Bali Starling Leucopsar rothschildi Stresemann 1912; its current status and need for conservation. ASEAN Workshop on Wildlife Res. and management. PHPA, Bogor, pp.115-31) Progressive conversion of forest into agricultural land; and the demand from the pet trade and worldwide aviculture, pressured wild stocks to the extent that in 1990, the total wild population was estimated to be as low as 13 (Balen and Soetawidjaya, 1991).

During the late 1960’s and throughout most of the 1970’s, probably several hundred birds were imported into the US and Europe. Lacking any great forethought or knowledge, most keepers lost their birds within a few years having failed to breed them. However, some pairs did breed. But the number of pairs was so small, and their breeding so prolific, that the NA gene pool suffered from greatly over represented bloodlines. At the same time, oversupply of these captive bred birds amply satisfied the limited zoo demand, and zoos found their birds increasingly more difficult to surplus. Market forces encouraged a downturn in captive breeding, and zoological interest in the species quickly waned.

In 1981 Bob Seibels, Curator of Birds at Riverbanks, started the AZA Bali mynah North American Regional studbook. At that time, there were only about 250 birds left in the wild, and the need for a captive breeding program was clear. Even clearer was the need for the degree of organization provided by a studbook, which in the US would later become part of an AZA Species Survival Plan (SSP©). A regional studbook is also maintained in the UK under the auspices of the Federation of Zoological Gardens of Great Britain and Ireland. And the European Association of Zoos and Aquariums manage the Bali mynah under a cooperative breeding program.

The Bali mynah is an endangered species and the international trade in it no longer exists. However, there is still a demand for Bali mynahs on the island itself as well as on neighboring Java. Birds end up as living trophies in the homes of wealthy and powerful Indonesians, in spite of the fact that the species has enjoyed complete legal protection, under Indonesian law, since 1970. Poaching of birds from the wild remains a thorn in the side of the project. Individual specimens are easily sold on the black market for between $1000 and $2000. Guarding the release sites, and the entire park in which the birds live, is one of the highest priorities, since it is thought that today there are only about 20 birds left in the wild.

Of course, on their own, the few birds that remain in the wild cannot sustain the species. The rate of reproduction alone is unlikely to keep pace with the natural death rate caused by disease, predation and famine. And the greatest problem of all -- lack of genetic diversity -- would surely condemn the species to extinction. The Bali mynah’s future lies in the approximately 250 specimens that live in NA zoos, plus roughly 500 more that live in zoos worldwide.

How it all started
In 1983 the wildlife division of the Indonesian government, the Directorate-General of Forest Protection and Nature Conservation (known as PHPA) formally asked the International Council for Bird Preservation (ICBP) to develop a conservation program aimed at recovering the national bird from the brink of extinction. In that same year, the Bali mynah was managed under an AZA Species Survival Plan (SSP©) which oversees all aspects of the mynah’s captive management and future release. By 1987, PHPA, ICBP, Jersey Wildlife Preservation Trust and the American Association of Zoo Parks and Aquariums, had created a 5 year cooperative plan which was aimed at restoring a viable and self-sustaining population in Bali Barat National Park.

The goals included
1. Monitoring and protecting the wild population
2. Establishing a captive breeding program in Indonesia
3. Restocking the wild population.

A further 3 year plan was agreed in 1992 which added the following goals to the original objectives:

1. Stop poaching
2. Reduce the demand for wild-caught birds
3. Establish new wild populations from captive bred stock

Captive breeding in Java
In 1987, Surabaya Zoo in east Java renovated an old breeding facility. It comprised 29 aviaries which at that time housed 16 Bali mynahs. Later that year, a total of 44 captive raised birds were transported from the US to Surabaya. The hope was that, together, these birds would form an adequate nucleus to provide specimens for release in the Bali Barat National Park on Bali itself.

The husbandry protocols used at Surabaya were provided by American zoos. The breeding aviaries were 2.5m high, 2.5m wide and 4m deep. Each aviary was well planted with shrubs and low trees, and housed only a single pair of birds. Unfortunately, breeding results during the first year were disappointing, and the following corrective measures were taken:

1. Aviaries were screened to prevent interaction with neighboring mynahs
2. Old nest boxes were replaced with designs more widely used in the US
3. Zoo visitors were kept away from the aviaries
4. Poor breeders were re-paired
5. More fresh, local fruits were added to the diet, along with livefood such as mealworms and ant pupae.

Following these changes, breeding did improve, although chick mortality was high. This was blamed on high levels of inbreeding, and later, diseases (mainly Atoxoplasmosis Isospora spp.) became the focus of attention and concern. In Jersey, evidence was found to link poor chick survivability with inbreeding; and in the US, an inbreeding depression was blamed for a reduction in fertility.

How many mynahs do we need in captivity ?
In 1990 a population analysis suggested that to be viable, it would be necessary to have 100 birds in the wild and 1000 more in captivity, with these two groups managed as a single population (Seal U.S. 1990. Bali starling Leucopsar rothschildi: Viability Analysis and Species Survival Plan, Workshop report, CBSG/IUCN, MN). Whether this can, or indeed needs, to be achieved, seems very uncertain. But at least it is obvious that the more birds there are, the greater the chances of preventing irreversible genetic deterioration. Today, the Bali mynah population is far better managed than ever before. Although the North American population is now roughly half of what it was in the early 1980’s, its genetic quality is considerably better. This has been achieved by promoting the breeding of pairs with known ancestry, and demoting the breeding of the others, while maintaining reasonable growth in the managed population.

Amnesty campagne
There are probably a significant number of Bali mynahs kept as pets and living trophies on Bali and neighboring Java. Being mostly wild-caught, these birds represent an important, untapped genetic resource which, if added to the breeding program, could be of great value. With this in mind, an amnesty campaign was introduced, which allowed illegally held specimens to be brought to the authorities without penalty. They would then be exchanged for genetically unimportant birds brought over from the US. Although numerous specimens have been taken to Indonesia for the campaign, the public response has been very disappointing, and to date very few birds have actually been exchanged.

Release program
In 1987, there were less than 50 birds left in the wild. A release was planned for the following year, but before that could take place, proper pre-release aviaries would have to be built. In June 1988, a facility was constructed in the Bali Barat National Park. This comprised 10 aviaries. Each measured 5 x 3 x 2m and resembled those already in use at the Breeding Center at the Surabaya Zoo. These aviaries are known as the Pre-release Training Center (PTC) and are used to familiarize the birds to wild conditions before release. The aviaries are shielded to prevent any habituation to people, including keepers. Soon after its completion in July 1988, the center received the first group of 3 birds from the Surabaya Zoo. They stayed there for 6 weeks in the hope that they could learn to forage for themselves while remaining afraid of people. This time was also used to familiarize the birds with the boxes that would be used to carry them to the actual release site.

Shortly after release, all of the birds died or could not be found. The failure was attributed to the dry conditions, the strong wind at the time of release, releasing the birds too far from existing roost sites and releasing too few birds (only 3). In 1988, 8 captive-bred birds were brought from Surabaya Zoo to the pre-release center on Bali. One died shortly after arrival and another was considered unfit for release. But 8 more birds were added to the group in 1990, and all were prepared for release. The second release was planned for an area in Bali Barat where other mynahs were known to roost regularly. Before release, the birds were fitted with colored rings, and transponders were also inserted. A simple cage was built at the release location to serve as pre-release accommodation. And all of the birds had a temporary red dye painted on their breast feathers to distinguish them, at least for the first few weeks. In April 1990, the first 4 birds were released from their cage where they had been housed for 2 days. During the following days, all of the other birds were released in 2’s or singly. Birds that were unfit for release remained caged so that they could attract the released birds back for food and water which was provided for 3 weeks. The release was very successful: mixed foraging, communal anting and mixed flocks of wild and released birds were seen roosting together.

They adapted to their new environment well, but the success of the release was hard to monitor as the birds became more wary and difficult to identify. Poaching at the release site was a major problem: within just 1 month of release, a bird identified by its unique transponder, was found in the hands of a local bird dealer. The concern therefore exists that others could have disappeared in the same way. However, 6 months after the release, one of the birds was seen 8 km away copulating with a wild bird; and another released bird raised 3 young in a tree hole with a wild mynah.

Medical aspects of the SSP©
In 1990, Terry Norton DVM, Dipl. ACZM. became the veterinary advisor for the Bali mynah program. Since then, considerable work has been done in identifying the diseases in the captive population. And with the help of other specialists, diet and necropsy protocols were quickly established. Iron storage disease (hemochromatosis) and Atoxoplasmosis are the two main areas of medical concern.

All keepers of Bali mynahs are asked to maintain their birds on low iron foods, along with fruits and insects. Like many birds, the starlings and mynahs are prone to accumulating an excessive amount of iron, which especially affects the liver. Although there are probably several causes of iron storage disease, high dietary iron is one important area that we can easily control ourselves. The iron level of a product may be described on its packaging, but often it is not, and a phone call to the manufacturer is the best way of getting the necessary information. Iron levels of about 100 parts per million are probably safe; and some products offer even lower iron levels. Other susceptible species include toucans and tanagers, and one would expect that all fruit eating birds have a degree of susceptibility. Certainly, practical experience suggests that toucans and starlings can be irreversibly damaged by high iron diets in only a few months: their lives are shortened and their chances of breeding greatly reduced.

Atoxoplasmosis
Another interesting and sprawling problem is Atoxoplasmosis, a disease caused by a coccidian parasite. The disease was first reported in Bali mynahs at the National Zoo in 1989, and since then, the organism has been found in mynahs in several US and Indonesian zoos. It is thought that young mynahs between the ages of 3 and 8 weeks die acutely from the infection. However, like coccidia, healthy adults tend to show no signs of the disease, and the organism is only revealed by microscopic examination of the feces.

Atoxoplasmosis remains a slightly mysterious organism. Now we have started to appreciate its existence, it has been discovered in several other avian species: white-eyes, oropendolas, and at Riverbanks, we think a recently imported leafbird may have been infected. If infected Bali mynahs are released into the wild, the fear is that they might infect other wild avian species. Work is currently underway at the North Carolina Zoo to try and determine whether the Bali mynah Atoxoplasma organism is species-specific, or whether it can be transferred to other species. Oocysts from Bali mynahs will be given orally to superb starlings to see if they undergo a complete life-cycle, or whether they simply pass through the gastrointestinal tract unchanged. The problem of course is that even if the disease is species-specific, captive bred Bali mynahs may infect Bali mynahs in the wild. We do not know whether the parasite occurs naturally on Bali, although it appears that it does exist elsewhere in SE Asia and S America. Some imported white-eyes and oropendolas have been found to shed the organism in the droppings.

What all of this means for the Bali mynah project is unclear. It is just one of the numerous problems that can affect and hamper any captive breeding program, especially when the objective is to release birds back into the wild.

Poaching and the black market
An important, and as yet unresolved, issue is how to reduce the illegal demand for the Bali mynah, and get rid of the crippling problem of poaching. If more birds were released today, most would be poached out of the wild and sold on the black market. How to deal with this problem is the subject of some controversy. One unconventional solution proposed by the Indonesian government is to sell genetically unimportant (captive bred) specimens in Indonesia to essentially flood the market and ruin the illegal trade. This may well work, but the plan raises several questions:

1) Would keepers in the US and Europe be willing to breed birds for this purpose ?
2) What would happen to the proceeds of these sales, since the sums of money could be tens of thousands of dollars ?
3) How many birds would have to be sold to destroy the illegal trade ?
4) As the price fell, would the demand for Bali mynahs actually be expanded beyond Bali itself ?

Like the medical aspects of the SSP, these too are thorny questions to which easy answers do not exist. At this stage, all that can be said is that doing nothing is likely to be worse than doing something, even if that something is unsuccessful.

Good news
With a project of this kind, communicating with workers in the field, whether they be American, European or Indonesian, can be difficult. For the Bali mynah project, getting up-to-date information has been all the more difficult, because it has never had a dedicated field worker in Bali. The ideal person would be an American college graduate, preferably with a degree in biology, who speaks fluent Bahasa and wants to live permanently in Bali. As you might imagine, this is an almost impossible vacancy to fill. But amazingly, in the last few months, such a person has been hired and very recently arrived in Bali, ready to start work. He will be an essential link to the American end of the program, and, via e-mail, will be able to provide frequent progress reports. So much work that is difficult or impossible to do from the US can now be completed in Bali, with face-to-face meetings held in the native language. What a breakthough. What promise the future holds.

This article was found at - Avian Scientific Advisory Group

Husbandry Guidelines For the Bali Mynah