When humans speak up, the little African birds called honeyguides listen—and can understand, a new study confirms for the first time.

Honeyguides in northern Mozambique realize that when a man makes a special trilling sound, he wants to find a bees’ nest—and its delectable honey.

Birds that hear this trill often lead human hunters to a nest, receiving a reward of honeycomb.

Communication between domesticated species and people is well known, but “the fascinating point in the case of the honeyguide is that it describes such a relationship between a wild animal and humans,” says behavioral biologist Claudia Wascher of Anglia Ruskin University in Great Britain, who was not involved with the new research.

“This has not been described scientifically before.”

Though the science may be new, the relationship isn't: Honeyguides and people have been cooperating in Africa for thousands if not millions of years.

View Images Yao honey hunter Orlando Yassene chops open a bees' nest in a felled tree in Niassa National Reserve. Photograph by Claire Spottiswoode

The bird’s job is to fly from tree to tree, calling and leading the person on, until the team reaches a bees’ nest. The person's—more painful—job is to extract the nest.

The oddball partnership arises from complementary skills and deficits. Honeyguides excel at locating bees’ nests, but a bird that tries to steal some of the tasty reward could easily be stung to death. (See "Hello, Honey! 10 Sweet Photos of Bees.")

Humans can help by wielding axes to chop bees’ nests out of trees and by lighting fires, creating smoke that subdues bees. But humans “are not so good at finding bees’ nests,” says study leader Claire Spottiswoode, a field biologist at the U.K.'s University of Cambridge and the University of Cape Town in South Africa.

Leading the Way

Previous research in Tanzania and Kenya had showed that humans score honey much more often if they have a bird’s help, but Spottiswoode and her colleagues wanted to find out whether information flows both ways.

They recruited volunteer honey hunters among the Yao people living in Mozambique's Niassa National Reserve. The Yao fish and farm but have little cash, making wild honey an important source of calories—and the best way to satisfy a sweet tooth. (Also see "African Elephants Understand Human Gestures.")

View Images A female greater honeyguide in the Niassa National Reserve. Photograph by Claire Spottiswoode

To call a honeyguide, Yao men make a specific sound, learned from their fathers, that Spottiswoode calls the “brrrr-hm.” While following a bird, Yao hunters continue to make the call to encourage the honeyguide’s efforts. The call is never used except during honey hunting.

In experimental forays by Yao men, a honeyguide was twice as likely to help when it heard the traditional “brrrr-hm” call than if it heard other words or sounds, the researchers report in this week’s Science.

The honeyguides were also three times as likely to lead the way to a bees’ nest if they heard a continuous chorus of “brrrr-hms” versus other sounds along the way.

The results show that “there is communication between humans and free-living wild animals that the animals understand,” Spottiswoode says.

View Images Part of the honey harvested from a bees' nest Photograph by Claire Spottiswoode

Urgent Work

Other scientists have shown that wild dolphins help fishermen boost their catch and in return catch more fish themselves, but it’s not clear that the two species send dedicated signals back and forth, the researchers say.

Spottiswoode says that honeyguides are probably born with some propensity for guiding others to honey but must learn to interpret the signals used by local people. (Read how animals are smarter than you think.)

View Images Yassene harvests honeycombs from a bees' nest in Niassa National Reserve. Photograph by Claire Spottiswoode

The new study is “important” verification of the cooperation between birds and people, says Brian Wood, an evolutionary anthropologist at Yale University not involved in the new research. He and Spottiswoode are now working together to explore how hunters elsewhere in Africa signal honeyguides.

There is some urgency to the work: More Africans are simply buying sugar rather than relying on their avian partners, meaning their unique connection could be waning.

At the moment, “there is still a rich cultural diversity” in how humans interact with honeyguides, Spottiswoode says.