Never mind the birds and the bees. What about the birds and man?

New research has revealed a new dimension to a bird-human relationship that focuses on the sounds both make.It has long been known that, in many parts of Southern Africa, humans and greater honeyguides can work together to find bees' nests from which the humans collect honey and the birds eat the honeycomb wax.A study in Mozambique by the universities of Cape Town and Cambridge shows that it is not only the birds' special call that keeps the relationship going, the humans have a "call" too.Lead researcher Claire Spottiswoode found that the "honey-hunting call" made by human honey-hunters - "a loud trill followed by a short grunt" - more than tripled the chances of a successful interaction with a bird.When the human made a different sound, the honeyguides were far less likely to lead them to the bees' hives, which are often hidden in barely accessible crevices high up in the trees.When the humans make the right call, the honeyguides lead them to the bounty and wait while the bees are smoked out."This reciprocal relationship occurs without any conventional kind of training or coercion."What's remarkable is that it involves free-living animals whose interactions with humans have probably evolved through natural selection over hundreds of thousands of years," she said.Cape Town bird enthusiast Ian-Malcolm Rijsdijk said: There has always been folklore about honeyguides [interacting with] humans."It would be almost bizarre for us to assume that such relationships did not exist between birds and humans."The research was published on Friday in the journal Science...