Mozambique – According to a new study, in some parts of Africa, birds and humans have learned to communicate with each other in the quest for finding food for both species.
In Africa and Asia, there is a species of bird commonly known as the honeyguides, which, as they name suggest, are known to lead humans deliberately directly to beehives.
Westerners first registered this behavior in 1588 when a Portuguese missionary who was living in Mozambique noticed a bird pecking at the candlesticks in his church. The tiny bird would also guide people to bees’ nests.
However, in the West nobody believed his claims, thinking it was just a myth. It was not until the eighties that westerners realized honeyguides were real, thanks to Kenyan birder Hussein Isack and German zoologist Heinz Ulrich Reyer.
The two men followed the Boran people of northern Kenya for three years and discovered a unique form of cooperation. The bird spokes to them with its fly, they just have to follow it.
If the honeyguide perches itself in lower tree branches and flies slowly, the hunters know they’re getting nearer. Most astonishing, if the bird makes a unique “indication call” and then stop, the human followers know they’re in the same area as the beehive.
Isack and Reyer found out that the Boran people take an average of nine hours to find a bee nest, with the help of the honeyguide, the time is reduced to three hours. From 2006, anthropologist Brian Wood from Yale University has found out that the Hadza people from Tanzania also use the honeyguide.
They rely on the bird so much that up to 10 percent of their annual calories come from honey. Using the bird leads them to richer nest that have as much as five times more honey than usual, and their increase their beehive-finding rate up to six.
The honeyguide also benefits from this arrangement, since the humans do all the hard work of using smoke to subdue the bees and breaking the nest, which can mean cutting down a tree. All the bird has to do is wait and then eat the wax.
Ornithologist Claire Spottiswoode from the University of Cambridge has discovered that is not always the bird the one that takes the initiative.
In the Niassa National Reserve Mozambique, the Yao people use a distinctive call (brrr-hm) for attracting the honeyguides.
This call is ancestral, passed down from generations through the fathers. Spottiswoode found out that the tiny birds start guiding twice as much when called by the brrr-hm sound than if they were being called with any other call, which shows there’s an actual form of communication between the Yao people and the honeyguide.
The researcher also discovered that the call is not just used for attracting the birds, but also to keep their attention. Keeping the brrr-hm sound during the hunt tripled the people’s chance of finding a nest. If they stopped, the honeyguide often left.
It is still a mystery how this partnership started, and how the honeyguides learned to communicate with their human companions.
What is certain, is that the bird’ behavior is not learned from its parents. The honeyguides do not raise their chicks since they are parasites such as the cuckoo.
The female lays her eggs in somebody else’s nest. The honeyguide chick always hatches first, and then, using a wicked spike on its bill kills the host’s chicks. The scammed foster parents then will focus their attention only on the honeyguide.
Then how the birds learn the signals?
Althoug it is unknown how this birds learned the signals, Spottiswoode thinks it may be in their genes, and that the chicks are born with the basics of guiding behavior, refining their technique by trial-and-error and by watching other adults.
The Yao people support this theory, since, for them, the youngsters are “rubbish guides” and only the adults are worth the time.
Once they have found the nest, the hunters make sure to pay their winged companions, with bits of wax and fresh leaves. Only the Tanzanian Hadza are an exception, according to Wood. He claims he has never seen them rewarding their guides.
The Hadza claim that giving the birds food will lower their motivation to keep looking for more bee nests. Spottiswoode and Wood have chosen to study together the various communications between the birds and the humans, depending on the location.
Still, another mystery is still unresolved: How did the honeyguides survive before they guided humans to their food?
The scientist believes these birds evolved three million years ago, way before the man discovered fire. The mystery becomes more baffling when one takes into account that the honeyguides are mostly nocturnal, and have awful eyesight and hearing.
However, this ancient custom is slowly dying. Now in Africa people can just buy honey from the beekeepers, so the idea of spending hours behind a bird does not make much sense anymore.
A paper about the study was published in the Journal Science, under the title ‘Reciprocal signaling in honeyguide-human mutualism’.
Sources: The Atlantic