A new study shows that birds and humans ‘talk’ to each other, as they partner up to hunt for honey bees nests together in the forests of Mozambique.
The honeyguide bird or ‘indicator bird’ is well known for its interaction with humans. One or two species will deliberately lead humans to bee colonies, so that they can feast on the grubs and beeswax that are left behind.
Greater honeyguides (Indicator indicator) are paleotropical near passerine birds related to the woodpeckers. The species is a resident breeder in sub-Saharan Africa, found in a variety of habitats that have trees, especially dry open woodland.
The greater honeyguide is about 50 cm in size. The male has dark grey-brown upper parts and white underparts, with a black throat. The wings are streaked whitish, with a yellow shoulder patch. The bill is pink. The female honeyguide is duller and lacks the black throat. Her bill is blackish. Immature birds are very distinctive, having olive-brown upper parts with a white rump and yellow throat and upper breast.
Honey Hunters Stick Together
For centuries, honey guides have been known to help African hunters find honey in the wild.
Guiding is unpredictable, but the behaviour is more common among immatures and females of the species, rather than among adult males. A guiding bird attracts a person’s attention with wavering, chattering “‘tya” notes, compounded with “peeps” or “pipes” sounds that it also produces in aggression.
Although the birds are better at finding the bees’ nests, they benefit from the human hunters’ ability to subdue the bees with smoke and break open the nest – a process that sometimes involves cutting down the tree.
The guiding bird flies toward an occupied nest, then stops and calls again. As in other situations, it spreads its tail, showing the white spots, and has a “bounding, upward flight to a perch”, which makes it conspicuous. If the human followers are native wild honey-hunters, they incapacitate the adult bees with smoke and open the nest with axes or machetes. After they take the honey, the honeyguide eats whatever is left.
Of Birds and Men
The Boran people of East Africa reduces their search time for honey by approximately two-thirds. Because of this benefit, the Boran use a specific loud whistle: the fuulido doubles their encounter rate with honeyguides.
In the Niassa National Reserve in Mozambique, the Yao people use a special call to attract the honeybirds, a loud trill followed by a short grunt: “Brrr-hm”.
Researchers wanted to find out if there was genuine two-way communication. They needed to know whether honeyguides responded to the specific information content of the “brrr-hm” call – which, from a honeyguide’s point of view, may effectively signal “Hello! I’m looking for bees’ nests” – or whether the call simply alerted honeyguides to the presence of humans in the environment.”
Spottiswoode et al. showed that when the honey-hunters make a specific call, honey-guides are both more likely to come to their aid and more likely to find them a bee’s nest. This interaction suggests that the birds are able to attach a specific meaning of cooperation to the human’s call – a rare case of mutualism between humans and a wild animal.
To make the distinction, the team made recordings of the “brrrr-hm” call, as well as of general human vocal sounds such as the hunters shouting their own names, or the Yao word for “honey”.
When you make the right noise, you end up with honey 54 percent of the time, compared to 16 percent of the time with the wrong noise. It is an exchange of information.
For evolutionary biologists like Claire Spottiswoode and her team, it is clear that the birds have adapted their behaviour through natural selection, but for people the arrangement is probably more cultural.