WASHINGTON — The hummingbird, a jeweled bullet, cut a belligerent circle around a pair of bemused titi monkeys perched high upon the sweating bough of a kapok tree and darted back to its perch on a vanilla vine.
"Did you see that?" exclaimed Michael Robinson. "That one's really frisky. But the monkeys'll eat a bird, you know, if they can get it."
The monkeys seemed unimpressed, twirling their tails sleepily in the steamy heat. Fine wisps of mist drifted through the dense, dank foliage.
"Oh God, it's just marvelous," gushed Mr. Robinson.
The Amazon jungle? A Hollywood film set? (After all, some of the trees are glass fiber dummies, although the animals are real).
No, this was Washington, D.C.; the Washington of monuments and parks, the Capitol, the White House and the impressive murder roll. And since yesterday, a Washington with its very own rain forest -- a "Brazil-on-the-Potomac," it's been called. But its formal name is Amazonia, and it's the newest addition to the National Zoo.
The complex opened yesterday in a ceremony attended by top officials of the Smithsonian Institution, which financed the $12 million project, and by the Brazilian ambassador, Rubens Ricupero.
Brazil, which has a large Amazon exhibit of its own and would clearly like Americans -- with their dollars -- to visit it, contributed artifacts, flew zoo scientists to Brazil and gave advice to enhance the authenticity of the exhibit.
With 358 species of tropical plants (including 50 types of trees); scores of mammals, birds, reptiles, fish, frogs and insect types; underwater viewing tanks, a hands-on field laboratory; and a separate (unfinished) science gallery, the 25,000-square-foot Amazonia center is the largest exhibit building to open at the zoo in more than 50 years, zoo officials say. The field laboratory, "abandoned" by an imaginary Dr. Brasil, has an "Indiana Jones-goes-to-Banana Republic" kind of look.
It is also a major step toward the dream of zoo director Robinson to go beyond what he considers to be a dated, one-dimensional concept of zoos as simply places where animals are kept.
"This is the future; we're headed toward a 'biological' park rather than a 'zoological' park," he explained. "The idea is to bring together all the different aspects of biology into one holistic experience -- something to which people can relate and which is truly educational.
"The practice of separating biological study centers -- having botanical gardens for plants, zoos for animals, aquariums for fishes and museums for paleontology -- is crazy."
On the face of it, Amazonia is nothing more than a big greenhouse with animals -- a structure big enough perhaps to house two tennis courts. But with hidden atomizer nozzles spraying mist, wildlife living within a natural cornucopia of trees, orchids, ferns and vines or swimming near the head of a rushing waterfall, and with humidity of around 80 percent at 82 degrees, visitors can easily imagine that they have stumbled upon a small piece of the real thing.
"What makes it especially realistic is that people actually have to look for the animals -- they won't always be easy to spot," said zoo spokesman Michael Morgan. He gestured at a nearby balsa tree where a sloth sat pondering its next move. In the root-bound stream below, a flotilla of blue-whiskered arawana fish cruised past nonchalantly.
Rain forests have become popular tourist attractions in several parts of the world, following the rise in popular concern over their depletion as human populations expand and bush-clearing and logging take their toll.
"Rain forests," said Mr. Robinson, who spent many years as a tropical biologist in Panama, "are treasure-houses of biological profusion and diversity, containing perhaps 90 percent of all animal species."
The National Aquarium in Baltimore opened its rain forest in 1981, and it has been a popular attraction, although many visitors are unaware that it exists until they are inside the aquarium, according to Chris Andrews, the aquarium's director of husbandry and operations.
Nicholas Brown, executive director of the Baltimore aquarium, scoffed at a suggestion that the National Zoo's rain forest, with its free admission, would draw tourists away from the aquarium, which charges visitors up to $11.50.
Fewer than 10 percent of the aquarium's 1.5 million yearly visitors come from Washington, he said. Besides, he said, the zoo and the aquarium are two very different experiences with their own attractions.
"When Mike Robinson told me about his plans, I said, 'Go, do it; do the same thing we've done,' " he added. "Everybody's talking rain forests these days; it's the new buzzword."
The Baltimore aquarium provided some tree frogs for the Washington rain forest, and some technical advice, according to Mr. Andrews.
"I would say the two exhibits are complementary," he said. "There are subtle differences, for example, in the fact that ours is a Central American rain forest while theirs is an Amazonian rain forest -- we have slightly different vegetation and animal life."
The Amazonia project, which began 26 months ago, is scheduled to be completed in 1994 when the educational gallery opens in a hall adjoining the rain forest. During this time it is also expected to expand its animal and plant collections.
"I like to think of it as a young wine," Mr. Robinson said. "It will take time to mature, for its flavor and bouquet to mellow."