updated 12/14/1992 AT 01:00 AM EST
•originally published 12/14/1992 AT 01:00 AM EST
Dumbacher, then a 24-year-old grad student trapping birds of paradise on a National Geographic Society expedition in the jungles of New Guinea, had his first brush with the pitohui in 1989 when several of the orange-and-black, blue jay—size birds became snared in his nets. Dumbacher nicked his hands on the beaks and claws of the birds as he removed them. Then he licked his wounds—and recoiled as his lips and mouth went numb. "I was scared and I tried not to swallow," he says. "I figured I had probably brushed up against some poisonous tree." After about four hours, Dumbaeher's symptoms subsided, and he relaxed. Two weeks later, however, the same thing happened to another researcher who had handled the birds—and Dumbacher began to wonder.
Unable to capture a specimen before the two-month expedition ended, Dumbacher returned to the U.S. to work on his master's degree at Clemson University and to dream about the pitohui. "I had to get back to New Guinea," he says. "The notion of a poisonous bird was pretty unheard of, and I had to verify it."
In 1990, on his second expedition in New Guinea, Dumbacher captured a pitohui. Then, he says, "I performed this very complicated and sophisticated experiment. I clipped off some feathers and popped them in my mouth," taking care not to swallow. Again he felt the numbing sensation. Clearly it was the pitohui itself—not some plant or tree—that was the culprit. His finding was confirmed, after a fashion, by local tribespeople, who considered the bird taboo. Some, he says, called it "good for nothing, a rubbish bird."
By the end of the summer, Dumbacher got permission from the government of Papua New Guinea to take four specimens back to the U.S. There he hooked up with John Daly, a chemist at the National Institutes of Health in Bethesda, Md., and embarked on a series of tests to isolate and identify the toxin. "I was very excited about what I'd found out," says Dumbacher, "but I also knew it wasn't enough—I needed some hard scientific evidence to establish that the pitohui was a poisonous bird."
Daly's first tests—done with tissue from dead pitohuis—detected a powerful poison, capable of killing mice within 20 minutes. Daly also determined that the bird tissue contained a steroidlike alkaloid, a very toxic substance, instead of the usual morphine and cocaine alkaloids produced by plants. This suggested that the toxin had been produced by the pitohui, not ingested.
In December 1991—after Dumbacher had made a third trip to New Guinea to get more specimens—Daly and Dumbacher concluded that the poison was homobatrachotoxin, precisely the same nerve agent that is secreted by poison-dart frogs of Central and South America. Administered mainly through the bird's feathers and skin, it is the pitohui's way of discouraging predators.
Dumbacher published his findings in the Oct. 30 issue of Science magazine. And the pitohui is, of course, the star of his Ph.D. thesis at the University of Chicago. Further research—on such questions as how the pitohui manufactures its poison and why the poison doesn't kill the bird—will, he says, "keep me busy for the next 10 to 12 years."
In the meantime the pitohui flies free in its native habitat in New Guinea's rain forests, relatively safe from predators—even human ones. Unless, of course, some entrepreneur should decide the quills would be perfect for writing poison-pen letters.
MICHAEL J. NEILL
BARBARA SANDLER in Chicago