英语语言学习：人类与响蜜列鸟
This next story is about a unique relationship between people and a wild animal, a bird called the honeyguide. Like the name suggests, this bird will deliberately guide people to honey. NPR's Nell Greenfieldboyce reports a new study by a woman who wanted to understand this unlikely game of follow the leader.
NELL GREENFIELDBOYCE, BYLINE: Even as a kid, Claire Spottiswoode loved birds.
CLAIRE SPOTTISWOODE: I've been obsessed with birds since I was about seven, so by then I was already a well-established nerd (laughter).
GREENFIELDBOYCE: The kind of nerd who would go the lectures at her local bird club in Cape Town, South Africa. That's where a scientist came to talk about his research on an African bird called the greater honeyguide.
SPOTTISWOODE: And I attended as an 11-year-old child and, of course, was transfixed and enthralled.
GREENFIELDBOYCE: He explained that this small, grayish bird was legendary. Stories had long told of how it knew the location of honeybee nests hidden inside of hollow tree trunks. It would tweet at people and flutter in front of them as it flew from tree to tree toward a bees nest. And the lecturer said this wasn't just a folktale. He'd done the first rigorous study.
SPOTTISWOODE: And by following honeyguides, human honey-hunters can really increase their rates of finding bees nest.
GREENFIELDBOYCE: The idea of a wild bird communicating with people in this way seemed almost magical to Spottiswoode, and she learned the birds got something, too. After hunters subdued the bees with smoke and hacked open the tree to harvest the honey, the birds ate the discarded beeswax, their favorite food.
Spottiswoode grew up to become a researcher with the University of Cambridge in the United Kingdom, and now she's done her own rigorous study of honeyguides in Mozambique. There, honey hunters who follow these birds rely on a distinctive call.
SPOTTISWOODE: It goes something like this (imitating honeyguide call) (laughter). So on the face of it, it's a rather unlikely noise.
UNIDENTIFIED MAN #1: (Imitating honeyguide call).
GREENFIELDBOYCE: That's a honey-hunter in Mozambique looking for a guide. And he finds one, or maybe the chattering birds finds him. What Spottiswoode wondered is whether that strange call meant anything special to the bird. To find out, she did a study, comparing the birds response to the call with a response to other nonhuman and human sounds like these.
UNIDENTIFIED MAN #2: (Foreign language spoken).
GREENFIELDBOYCE: He's saying, "honeyguide and human" in the local language. It turned out the random sounds didn't really appeal to the birds. They'd guide people only about a third of the time. But when they heard...
UNIDENTIFIED MAN #1: (Imitating honeyguide call).
GREENFIELDBOYCE: ...They guided people two-thirds of the time. Overall, making the special call more than tripled a hunter's chance of finding honey. The study is written up in the journal Science, but the dry analysis doesn't really capture how Spottiswoode felt as she talks to a little, wild bird that listened and led her through the trees.
SPOTTISWOODE: I don't think I've ever had as much fun I've had in my life (laughter). Yes, perhaps that shows what a sheltered life I've led, but it was tremendously good fun.
GREENFIELDBOYCE: Honeyguides don't get trained like falcons. No one breeds them like dogs, yet somehow they responded to specific human calls.
RICHARD WRANGHAM: This is really an extraordinary relationship.
GREENFIELDBOYCE: Richard Wrangham is a biological anthropologist at Harvard University. He says, why would birds team up with humans?
WRANGHAM: The critical feature of the relationship is the fact humans have fire as well as axes.
GREENFIELDBOYCE: The tools that let of them harvest honey. That's why Wrangham thinks this collaboration might go back more than a million years. The birds may have evolved an innate desire to guide people to honey. Still, they're probably not born knowing what human sounds to listen for. That's because people in different parts of Africa called the birds in different ways. For example, in Tanzania, people whistle at that the birds.
UNIDENTIFIED PERSON: (Whistling).
GREENFIELDBOYCE: So how does a wild bird learn which human sounds matter - maybe from other birds, but scientists aren't sure. Nell Greenfieldboyce, NPR News.
