One of the most important objectives of the North Carolina Zoo is to maintain viable populations of exotic animals for its own collections and for the collections of other zoos around the country.

The zoo has been especially successful in the keeping and breeding of rare and exotic birds and, over the years, has been responsible for a number of the most significant bird hatchings in American zoos.

The latest example is the red-faced liocichla (pronounced leo-SIC-la). This species, native to China and Southeast Asia, is abundant in the wild, but there are only nine known adults in captivity in America. Of those nine, seven are now housed at the N.C. Zoo. The zoo has been working with the species since the mid-to-late 1980s and this year, had four hatches, of which two have survived.

"A couple of years ago, we went looking around for some mates for some of our (liocichlas) and realized that there was only the small number left," said Ken Reininger, curator of birds at the N.C. Zoo. "We made a concerted effort to gather up as many as we could to breed them, and it has not been easy."

Liocichlas, like some of the zoo's other rare species, are considered passerines, an order that includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders -- with about 5,093 species.

Although the number of species in captivity is small, their management is far from easy.

"It does take a concerted effort by all zoos pulling together to monitor what is going on -- to track things like genetics and the sex ratios and the age structures of these populations," Reininger said.

Another of the zoo's rare passerines is the golden-head manakin, thought to be housed by only two or three other zoos. Only one has been successfully raised in captivity.

Because of parasite problems in previous chicks of this species, the last two born at the zoo were hand-raised but were still lost because of their fragile nature. (They weigh less than one tenth of an once at birth.) Zoo staff considered it a success just to get them to the fifth day after hatching. Even such renowned zoos as the San Diego Wildlife Park, considered a leader in rare and exotic-bird breeding, had managed to have one survive only three days.

The N.C. Zoo is the only facility other than the San Diego park even to have nestings and hatchings of these manakins.

Another of the N.C. Zoo's rare species is the golden white eyes, a species that was brought to the zoo as part of a translocation rescue effort in the South Pacific's Mariana Islands. Shortly after the brown tree snake was introduced to the island, many bird species, including the golden white eyes, began to disappear rapidly.

The N.C. Zoo was approached about participating in the rescue effort because of the park's reputation for being able to breed and keep small, delicate species such as these passerines.

Since no one has worked intensively with this species, it is uncertain how they can best be bred and kept at the zoo -- in large exhibits with other species or in small holding areas by themselves. But the zoo staff will try to find the best situation for them and share that with other facilities housing the birds.

Another of the zoo's interesting bird species is the Bali mynah, native to Indonesia in Southeast Asia. Although they are plentiful in captivity -- with 200-250 in North American zoos alone -- there are thought to be less than 10-20 of them in the wild. Many experts think that they could even be extinct in the wild.

Yet the species' captive population is now so plentiful, through the efforts of captive breeding, that their reproduction is actually controlled to ensure that bird facilities don't breed more than available space allows.

Through programs such as these, the zoo will continue to maintain viable populations of rare, exotic and endangered birds, ensuring that zoo visitors throughout the world can enjoy these fascinating creatures for generations to come.

Zoo visitors can see all these rare and exotic species daily in the park's R.J. Reynolds Forest Aviary exhibit.

Tom Gillespie works for the public affairs office of the N.C. Zoo.