Birds Drongo fraud or thinkers? Bashny.Net

 

    




African bird Drongo is able to anticipate how to behave like another animal, say the biologists from South Africa. Until now, such abilities were considered a "monopoly" man.

Funeral Drongo, African warblers with a glossy black plumage, forked tail and bright red eyes, known for their trickery. They mimic the alarm signals of other species of animals and birds to spook them and under the guise to steal their food. Tactical sophistication of the Scam-Drongo, which has recently been observed in experiments, was so impressive that some are willing to attribute the birds ' cognitive abilities, which is believed to be unique to humans.

Evolutionary biologist from the University of Cape town Tom Fowler (Tom Flower) since 2008, studying a colony of Drongo in the reserve in the valley of the Kuruman (Kalahari desert). He accustomed to their presence and banded about 200 birds.

In the ecosystem drongos play the role of a burglar alarm. Noticing the predator, the bird produces a characteristic "metallic" alarm cry. Other types of animals – meerkats, timely (bird of the family Drozdov), highly social neighbors Drongo on the ecosystem, using their presence "to save on the lookout". But this saving has a price: not always and not every Drongo honest, raising the alarm. Sometimes meerkats, catching a fat Gecko, throws the prey and hides on hearing the warning cry Drongo, although no predator nearby and there was not. The Gecko in this case the evil one bites the signalman. Thus, according to previous studies, Fowler, Drongo receives approximately 23% of their daily diet. Meerkats, for example, tend to quit the prey, and to hide regardless of the false alarm raised Drongo or real.





In addition, the Drongo mimics the anxious cries of many other animals, all the researchers registered in their Arsenal 51 different signal. Six of them is "native" signals themselves Drongo, varying depending on the threat type, and the remaining 45 – alarm signals of other species. Flower argues that the representatives of all these types of warning signs to recognize each other and respond accordingly, as if "understand each other's languages".

But what is the advantage of getting Drongo imitating the cries of other species? To understand this, flower and his colleagues conducted a series of experiments, the object of which chose Drozdov timely. It turned out that after the "fake" cry Drongo – mimicked their alarm themselves timely or starlings – scared by birds stayed away from the compromised area (food source) is longer than after a disturbing cry themselves Drongo. In addition, after the same alarm signal was fed three times in a row, timely ceased to react to it, but when the third was the signal for a new character, fluttered and flew, as in the first two cases. The experiments showed that Drongo evolutionary advantageous to have a rich "repertoire of disturbing," according to Fowler, it allows them address to use the cries of different species of animals.

What they are doing. 42 observing marked individuals, flower colleagues recorded 151 case when a Drongo was making repeated attempts to steal food from the same victim, scaring her, "the alarm", and in 74 of these cases, by repeating your false signal, they "changed his language." This is mainly done in cases, when the first signal did not cause the expected reaction. Scientists were also able to show that the change of "language" signal brought the fraud to succeed.

Flower believes that Drongo have a remarkable ability to respond flexibly to feedback from the intended "victim", thus solving the problem of "Wolves! Wolves!".
Experts are not unanimous in the interpretation of experimental results. On the one hand, this suggests that Drongo possess exceptional cognitive abilities that allow them to anticipate how to behave like another animal that is still considered the prerogative of man. On the other, the degree of "tactical intelligence" behavior can be explained by simpler associative learning: "another animal runs away after the alarm; change the alarm until it run off."

Flower, convinced that Drongo at least able to "understand" behavioral causation, preparing new experiments to understand what is going on in the mind of this ingenious bird.

 

 

Source: nkj.ru