For the Bali Mynah
I. Housing and Enclosure Requirements
Bali mynahs appear to be quite adaptable in housing requirements. They have been successfully maintained in a wide variety of enclosures from small breeding units to large free flight aviaries.
a) Containment Barriers
Enclosures may be constructed of wire or plastic mesh or of a solid barrier material such as glass, wood, fiberglass reinforced plastic sheet, or concrete. Bali mynahs are very inquisitive and persistent animals and are capable of poking their beaks through soft plasters and insulation materials. Containment barriers should not be made of these materials and should prohibit access to any such materials. Woven or molded polypropylene mesh may not stand up to damage done to it by Bali mynahs over extended periods of time. Barrier material openings should be 2.5 cm x 2.5 cm (1" x 1") or smaller (in at least one dimension) to prevent escapes or injuries from entrapment in the mesh. Barrier material should exclude snakes and rodents to whatever extent possible. Glass impact mortalities have not been a significant problem for Bali mynahs housed in enclosures with glass containment barriers. However, due to the likely occurrence of intra-specific aggression between breeding pairs it is important to place an opaque barrier between pairs housed in close proximity to one another.
b) Shelter Requirements
For protection from precipitation and wind a covered area is necessary whenever birds are housed outdoors. Bali mynahs seem to fare well in either indoor or outdoor enclosures, being able to tolerate temperatures into the low 40s °F (5 - 7°C) if protected from wind and dampness. However, birds exposed to these low temperatures should be gradually acclimated to them and monitored closely for individual tolerances. Birds which are physically compromised should not be expected to tolerate these lower temperatures. Ideally, outdoor aviaries should have an attached heated indoor room to avoid exposing birds to these lower temperatures. Bali mynahs should be provided with shady areas out of the direct sun. These can be naturally planted areas or artificial shade structures. As mentioned above, protection from native predators common to the area should be provided.
Easily cleaned substrates are preferable. Bali mynahs may come to the ground in search of insects or other food items and may dig around in leaf litter searching for food. However this species is arboreal and health concerns with substrates relate more to pathogen harborage (e.g. Atoxoplasma) where regular and thorough cleaning is not possible. The birds seem to settle in better in well-planted open aviaries. Birds may develop various stereotypic behaviors in sterile cages. Feather plucking can be a problem in both well-planted and sterile exhibits. However, enclosures with furniture that supports natural behaviors can help reduce or eliminate stereotypical behavior.
d) Water Source
Fresh water may be provided in bowls or shallow water features. The drinking water source should ideally be elevated, as birds feel more comfortable drinking and eating from an elevation. Opportunity to bathe on a regular basis should be provided in the form of a shallow water bowl or water feature, or a misting device.
Perches should average 1.25 - 2.5 cm (½" to 1") in diameter. They should be placed high and in areas of the enclosure the birds are likely to feel most secure. Bali mynahs are arboreal feeders, spending most of their time in trees and shrubs. Natural branch perches are preferable and these should have lightly rough bark. Perches should be kept free of fecal build-up and should be checked frequently for signs of wear. Perches of inappropriate diameter or worn smooth from use can lead to health problems such as bumblefoot.
f) Temperature and Humidity Requirements
The range of the wild Bali mynah is restricted to the Indonesian island of Bali, located at roughly 8 degrees south latitude. Bali has a tropical monsoon climate with distinct wet and dry seasons. Average daily temperatures of 27° C (80° F) with 75 % relative humidity are typical of the fire induced open scrub and lowland (below 175m altitude) monsoon forest where the species is found. These are the conditions for which Bali mynahs are adapted. Bali mynahs can tolerate temperatures as low as 5 -7° C (the low 40's °F) if protected from wind and damp conditions (see section b above). High temperatures can be dangerous. However, healthy, acclimated birds may safely tolerate temperatures up to 100° F so long as they have adequate shade and misters. A safe range would be 18 - 30° C (65° F to 85° F) without sudden changes. Bali mynahs tolerate moderately high humidity without any obvious signs of stress. For birds housed indoors where a dry forced air heating system is used, low humidity could be a problem. This condition can be rectified with a humidifier.
g) Minimum Acceptable and Optimal Size of Enclosure
The minimum acceptable size for a breeding aviary is 1.2m x 2.1m x 4.5m (4 ft x 7 ft x 15 ft). In this small enclosure, one pair of mynahs must be the sole occupants. By arrangement with the
h) Capture and Handling Facilities
Bali mynahs kept in free flight aviaries can often be caught in simple food traps or via hand-held nets or mist nets. Methods used will vary with enclosure conditions. No special handling facilities are needed. However, in large aviaries, a trap/release cage would facilitate low stress captures and releases. The birds would be fed in this cage daily; having no fear of it, they could be more easily caught when necessary.
If access to natural light is not available, artificial light should be provided. The artificial photoperiod should be approximately 12 hours long to mimic that in Bali.
j) Isolation from Same or Similar Species
As with most mynahs, this species can harass other birds, including other Bali mynahs. In large enough aviaries, Bali mynahs have been kept with a wide variety of birds without difficulty . However, they are nest robbers if given a chance and will remember raided nest locations for future reference. Conflict with any nesting species can and should be expected.
a) Individual Identification Methods
Standard aluminum butt-end bands are the most common method of identification employed with perching birds. These may be augmented with various types of plastic color bands to aid identification at a distance. However, experience has shown that plastic bands often fade over a period of time, and also tend to be less durable. They therefore should not be used as the primary means of identification. Transponder chips are now being used at a number of locations as a more permanent and less visible method of identification. IUCN/CBSG has designated the Trovan brand as the unit of choice. Unfortunately, for several years the Bali mynah SSP has been utilizing a competing, incompatible, brand (Destron) to mark the birds which have been returned to Indonesia and those released into the wild. To avoid confusion, we will continue to use this brand for any birds that are marked for return to Indonesia. The IUCN/CBSG recommended transponder implant site is in the left pectoral muscle. If your birds have been equipped with transponders, please be sure to indicate the brand as well as the number/letter sequence on any correspondence with the studbook keeper.
b) Recommended Methods of Capture, Handling and Restraint
Lightweight hand-held bird or insect nets of approximately 25 cm (10") in diameter should be used to avoid injuries and damage to plumage during capture. The most comfortable method for hand restraining birds is to position them with the head protruding between the index and middle finger, while using the thumb to encircle one wing and the little and ring fingers around the other wing. The bird should be held loosely enough so as not to restrict respiration while still maintaining control. It is recommended that hand restraint using this method should generally last no longer than 10 minutes. Healthy Bali mynahs typically emerge from this type of capture and restraint without being excessively stressed. (Also see Immobilization under Health section)
c) Recommended Crating and Transport Procedures
Shipping containers should conform to
d) Pest Control
Like all sturnids, Bali mynahs opportunistically eat many types of insects, including cockroaches. This is an unavoidable activity, and should be controlled by reducing the resident cockroach population. Cockroach populations must be kept under control, as they represent a genuine threat to captive birds. Their exoskeltons can present impaction problems (especially for young birds), and they are a vector for the transmission of disease. Rats and mice are capable of both transmiting and causing disease. Rats can eat both chicks in the nest and adults. Snakes (particularly the black rat snake Elaphe obsoleta) are a serious threat in areas where the birds are maintained outdoors, or where they can gain access to the birds enclosures. Snakes are capable of eating both young and adult Bali mynahs. All of the abovementioned pests are life-threatening. Because of this fact, pest control should be a consistent, ongoing process.
III. Behavior and Social Organization
Studies of the annual movements of the remaining wild population suggest a seasonal pattern of distribution. The entire population was found in one area of 250 - 300 hectares during the rainy/breeding season, but historically dispersed into smaller groups of 20 - 30 birds which gathered at communal roosting trees during the dry season. Breeding pairs of Bali mynahs establish territories at the onset of the rainy season in October and November. A home range of 2.4 to 3.5 hectares per breeding pair has been reported and this may be typical. There is an indication that breeding pairs maintain territories to some extent throughout the year. After establishing a territory the pair will begin to bring twigs, grass, feathers and leaves into a suitable tree cavity within the territory. They have been observed defending the immediate area surrounding the nest hole from black-winged starlings Sturnus melanopterus and spangled drongos Dicrurus bracteatus, possible food and nest site competitors. In favorable wet seasons, Bali mynahs often raise 2 to 5 young per clutch. After fledgling, wild juveniles stay with their parents for a few weeks after which they join juvenile flocks guided by a few adult birds. Non-breeding and immature birds will roost within the breeding area of the adult population, but roam over large distances to forage.
For the purposes of breeding in captivity, it is recommended that one pair of mynahs be the sole occupants of their aviary. In a very large enclosure, they may be housed with other birds, but their penchant for nest robbing should be carefully considered. Single sex groups can also be maintained in large enclosures by arrangement with theSSP Coordinator. It is advised that breeding pairs be kept in visual isolation from other Bali mynahs. All new pairings of Bali mynahs must be coordinated by the Studbook Keeper and SSP Coordinator to properly manage the genetics of the captive population. Although it is rare to see aggression between birds, it is advisable to introduce a new mynah to its intended mate through use of a "howdy" (introduction) cage or by putting birds in adjacent cages where they can see and hear each other for several days prior to direct introduction. Regular monitoring of the new pair over the first few days after direct introduction is recommended.
Courtship between Bali mynahs observed in captivity includes a head bobbing display in which the bird erects its crest, points its bill upward and bobs up and down; loud clucking vocalizations and mutual preening also occur. This behavior is not limited to the pre-nesting period, however, and may even be performed by two birds of the same sex. Excessive preening may lead to a feather plucked condition often seen in captive birds. Although this does not appear to inhibit breeding, it creates birds that are sometimes unsuitable for exhibit and certainly inappropriate for return to Indonesia. The causes of severe feather plucking are unclear, but since it is not seen in the wild population, it is probably linked to the birds captive environment and lack of appropriate stimuli. Therefore, sterile (unplanted) environments should be avoided.
When Bali mynahs are kept in large mixed exhibits, it is recommended that the young birds be removed from the exhibit as soon as they leave the nest box. This should occur between 21 and 24 days after hatching. If immediate removal is not possible, all water pools in the exhibit should be drained to prevent accidental drowning. As an alternative to pulling the fledglings they could be moved to a small wire mesh cage through which the adults can feed them.
Sex determination: The bird should be banded and blood (or a blood feather)
collected for sex determination. Alternatively, some institutions may choose to
laparoscope the bird.
Bali mynahs nest in suitably large and reasonably secure tree cavities in the wild. These are usually old excavations of woodpeckers or barbets, or natural cracks in old trees. Bali mynahs have not proven to be very particular in accepting nest sites made available in captivity. Broods have been raised in man made nest boxes, hollow logs, in underground holes and even on building heating system radiators. They do prefer the nest site to be located as high as possible, while still being accessible. One common selection criterion seems to be a nest entrance hole the birds need to squeeze through.
A successfulnestbox design presented in the 1990 Bali mynah North American Regional Studbook is a hexagonal box 75 cm (30") long and 15 cm (6") in diameter, constructed of ½" or ¾" plywood. The nest entrance hole should be 5 cm to 5.7 cm (2" - 2¼") in diameter. A hinged or sliding track cleanout door should be built into a side of the box (away from the entrance hole) to facilitate nest inspection and management and to allow for easy cleaning. The nest is characteristically lined with grasses, twigs and leaves by the parent birds. Bali mynahs will often use the same nest box for multiple clutches and can build one nest on top of the other until the next box is full. It is recommended that old nest material be removed between nesting attempts.
Incubation period - 13 days; incubation duties shared by both sexes
Breeding season - November to March in wild; throughout the year but concentrated March to September in captivity.
Clutch size - 3 in the wild; 1-5 (average 3-4) in captivity; eggs laid at 1 day intervals; unmarked blue color of average dimensions = 30 mm length x 21 mm width; average fresh egg mass = 7.14 gm
Chicks per clutch - in captivity 2.05 with range of 1-5 (average of over four hundred clutches; data does not indicate how many eggs were in each clutch).
Sex ratio at birth -Although the available information is not complete, it appears that the sex ratio is fairly equal. (Few if any records on sex of dead in the shell chicks and early embryo deaths exist.)
Physical development- Chicks normally hatch over a 12 - 24 hour period and are fed by both parents. They are naked and blind at hatching, and pin feathers begin coming in during the first week. They are completely feathered by two weeks.
Age at fledgling -21 - 24 days.
Age at first breeding - less than one year.
Feeding Schedule and Feeding Locations
Fresh food should be provided daily, on an ad libitum basis. Like most arboreal perching birds, Bali mynahs are not comfortable on the ground, and prefer to eat and drink from elevated platforms. In large, mixed-species exhibits, it is recommended that food be provided in semi-enclosed feeding stations with a trap door to facilitate capture.
Diet and Feeding Interval
Like other members of the family Sturnidae, Bali mynahs are omnivorous. Preferred food items in the wild include seasonally available fruits of native trees and shrubs, a variety of insects and even small reptiles. Historically, they have been maintained in captivity on a multitude of diets, most being a mix of chopped or diced fruit and high-protein items such as dog or trout chow or mynah pellets, along with bits of raw meat (ground beef, Bird-of-Prey diet) and hard boiled egg. Bali mynahs, as well as many other captive birds, are susceptible to hemochromatosis or "iron storage disease" (see Health section). The complete etiology of this disease is unknown. However, one theory proposes that it is associated with high levels of iron in the diet.
Therefore it seems prudent to recommend that the diets for Bali mynahs contain levels of iron no higher than the range recommended for domestic species. Recommended values for poultry are approximately 66.7mg/kg dry weight of diet; it is suggested that this be the target value for the total diet eaten by the birds. Commercially prepared "Low Iron" pellets are available from a number of sources, however not all of these products have iron at or below the levels recommended. Diets should be designed to come as close to these iron levels as possible.
Products such Tropical Bits and Red Apple Jungle have been used successfully over a long period of time for species, such as sturnids and ramphastids, that are susceptible to iron storage disease. The iron content of these (Marion) products is about 105 ppm.
P.O. Box 875
Wayzata, MN 55391
"Red Apple Jungle"
Manufacturers of nutritious cricket food
|Mazuri Purina Mills, Inc
P.O. Box 66812
St. Louis, MO 63166-66812
Manufacturers of nutritious cricket food
|Reliable Protein Products, Inc.
70-105 Frank Sinatra Drive
Rancho Mirage, CA 92270
Manufacturers of "Softbill Fare"
|Zeigler Brothers, Inc.
P.O. Box 95
Gardners, PA 17324
Manufacturers of "Bird of Paradise Pellets"
Manufacturers of nutritious cricket food
|Harrison's Low Iron Maintenance Diet
Guenter Enderle Enterprises, Inc
27 West Tarpon Ave
Tarpon Springs, FL 34689
(813) 938 1544
FAX 938 1545
Manufacturers of nutritious cricket food
Manufacturers of calcium, phosphorus and mineral supplement "MSA"
Live food should be offered in moderate amounts. Outside of the breeding season live food should comprise no more than 5% (by weight) of the whole diet. During the rainy season in Bali there is an abundance of fruits and insects, which plays a role in triggering breeding activity. Hence in captivity the supply of live food can be increased during the breeding season to stimulate nesting. Mealworms are by far the most common live food offered, although crickets, waxworms, corn grubs and more obscure forms of live food have been used successfully. It is advisable that live food items be fed a commercial diet such as Zeigler Cricket Diet, Nekton Cricket Concentrate, Mazuri Hi-Ca Cricket Diet or Marion Cricket Diet for a minimum of 48 hours prior to feeding them to the birds.
When parents are feeding young, it is absolutely necessary that a ready supply of live food is available at all times during daylight hours for the first seven days after hatch. As has been noted already, mealworms are a preferred item. Parents will carry as many as a dozen mealworms up to the nest at a time. Impaction of the chicks due to the hard chitinous exoskeletons of the mealworms has sometimes been cited as a problem in other species, but does not seem to be significant with the Bali mynah.
A 100-gram bird requires 25-50 kcal daily to meet maintenance energy requirements, depending on activity level and any additional energy demands (such as cold temperatures). An example of a diet that meets known nutrient needs for one bird includes:
25 grams proprietary softbill pellet (such as one of the abovementioned brands)
15 grams of diced fruit
7 grams of mixed vegetables
5 grams of minced leafy greens
About 1 gram of livefood (such as mealworms, waxworms or crickets) per bird per day. This should be increased when chicks are being reared.
A balanced calcium, phosphorus and mineral supplement, such as Nekton MSA, should also be used according to the manufacturers' instructions.
In general hand-rearing is not recommended. However, under certain circumstances the SSP may recommend hand rearing on a case by case basis (eg when a genetically important pair has repeatedly failed to raise its own chicks). Hand raised specimens monitored in this studbook have bred and subsequently raised their own offspring on several occasions.
VI. HealthMedical Protocols Recommended by the US Bali Mynah SSP