Yao honey-hunter Orlando Yassene holds a wild greater honeyguide female in the Niassa National Reserve, Mozambique. (Credit: Claire N. Spottiswoode)
To find hidden bee hives, Yao tribesmen get “honeyguides” (Indicator indicator) to help them. Tribesmen emit a distinctive vocalization to call the birds to help them with a honey hunt says a paper published July 22 in Science. The birds know the difference between the "hunt" call and other sounds made by tribesmen. Many other tribes have the same relationship, but use different calls or whistles for the same purpose.
By themselves, the birds are unable to break into the nests. With the birds’ help, tribesmen find behives much more often. This mutualistic relationship between the birds and hunters dates back further than tribesmen's oral history, but has only been documented in scientific literature since the 1980's.
The birds are not trained, and they live freely in the wild. Their "interactions with humans have probably evolved through natural selection rather than any artificial selection on our part,” says Spottiswoode, a co-author of the paper. Since honeyguides are brood parasites, (like the cuckoo they lay eggs in other birds’ nests and let the other birds raise them). So this behavior is not learned from their parents. While it is possible that there is a genetic reason that they are attuned to human calls, it is unlikely since the behavior is so widespread among far-flung groups of Honey Hunters. It is most likely that they learn from older Honey Hunters.