Captive Breeding of the Fairy Bluebird at the San Antonio Zoo

Abstract

On a recent birding trip through the Malayan peninsula, I heard the distinctive call of the Fairy Bluebird, Irena puella, and looked up to see four or five males flying overhead. The electric blue and velvety black of their plumage shimmered in the sunlight. Although I see them every day in their exhibit in the Hixon Bird House, the sight of this small group flying freely in their natural habitat and the sound of their exuberant whistles and calls was a memorable experience.

These lively, mainly fruit-eating birds live in pairs during the breeding season or small groups the rest of the year in the evergreen lowland forests, up to 4000 ft (Delacour, 1947). Five subspecies are distributed from India, Burma, Thailand, Malaysia to the Philippines and Indonesia; they vary very little in color (Rutgers, 1969). In Borneo, they play a role in the pollination of Erythrina and Grevillea bushes which provide shade to the coffee plantations. The pollen sticks to their chins as they travel from bush to bush (Rutgers, 1969).

On the Malay peninsula, they were actually called "Coffee birds" due to their fondness for eating the ripe berries of the coffee bushes (Astley, 1910).

Their nests are lined with rootlets. The female lays two pale blue-gray eggs speckled with brown, gray or purple markings (Grzimek, 1968). The juvenile chicks have the female coloration for the first six months, which is a duller, verditer blue. At this age the males begin to get black feathers on their head and breast (personal observation).

According to the latest ISIS, there are 56.54.15 Fairy Bluebirds in zoos in North America, while in 1982 only 61 individuals were listed. Is this increase due to captive propagation or increased importation? Unfortunately it is the latter when it should be the former. For the last decade, it has been the fourth most commonly held passerine in North American

zoological collections (Webster, 1993). For such a popular and important species, breeding success should be more reliable.

The bloodlines and genetic diversity of zoo-based Fairy Bluebirds are managed by a studbook organized by the Toledo Zoo. Although many of the wildcaught birds in zoos have reproduced so that inbreeding is not a problem, the success rate has been unsatisfactory. Captive breeding has been erratic as there is a difficult period at their fledging time, days 11 to 17 (Bohmke, Silveri, 1988). What appear to be healthy chicks often die during this period. This happens whether they are parent-reared or handreared and for various reasons. In a survey of 34 zoological institutions, compiled by Ann Silveri and Bruce Bohmke in 1988, parents were able to fledge only 43% of their chicks and handrearingyielded only an 11 % success rate.

San Antonio Zoo Birds

In 1993, the San Antonio Zoo has had more success than in the past in breeding Fairy Bluebirds. San Antonio Zoo has two pairs of this species; one in a mixed species exhibit, indoors, that is 18 ft wide by 18Yz ft deep by 13 ft high and the other in the off-exhibit propagation area called the Avian Reproduction Center (ARC), which measures 8 ft wide by 7Yz ft high by 16 ft deep. The substrate is a bark mulch and both areas are heavily planted. The two pairs were successful iri raising chicks in 1993 due to a change in protocol initiated in 1992.

In 1992, one pair's first clutch (two chicks) died during that mysterious period, on day 12. When they produced a second clutch, we removed the chicks and were able to hand raise one of them. The one-year-old bird is doing very well, and was named "Blueberry" after its favorite food item!

With the next clutch we decided to try removing the male as soon as the second egg was laid (between 24 to 48 hours after the first egg). The Denver Zoo had tried this with positive results during their 1990-91 season, although they left the male with the female until just prior to the chick hatching (Chacon, 1992). We kept the male within visual and calling access to the female to maintain the

pair bond. 

We found this to be an excellent solution. The male is in visual and auditory

contact with the female yet unable to harass or destroy the eggs or chicks. The incubation period is quite rapid, 14 days, and the period to fledging equally short, and the female was quite capable of incubating and feeding the chick on her own. We also began offering a large bowl of free-choice crickets, mealworms and waxworms several days before the chicks were due to hatch.

We tried this same technique in our mixed species exhibit. When the female laid her second egg we removed the male. Again the female was able to incubate and raise the chick on her own. We would like to take this one step further this year and put the male in a "howdy" cage and keep him in the exhibit.

In most clutches, although two eggs were laid, and often two chicks hatched, only one chick fledged per clutch. The female begins incubation with the laying of the first egg, so that the chicks often hatch a day apart, which probably puts the second chick at a disadvantage. In one case, two chicks hatched and we pulled one for handrearing and left the other to be parent reared, and both chicks survived. This technique also was used in Denver, where they pulled the secondchickatdayseven (Chacon, 1992).

Nests

Another factor that may influence breeding success is nests. Many of the Fairy Bluebirds currently in zoo collections are not reliable breeders. We feel that this may be due to inadequate breeding stimui in the captive environments. Many of the birds in the captive population are wild-caught birds and may be missing the native plant fibers used for nesting material.

We have found an interesting solution to that problem: we offer our birds Greattailed Grackle Quiscalusmexicanu nests. We soak the nests in diluted bleach for 15 minutes and set the nest in a grapevine frame to support it. Additional hay is also provided. The Fairy Bluebirds respond immediately and are nesting within several days.