(CNN)Complex societies were thought to only exist among mammals, including humans, other primates, elephants, giraffes and dolphins.
But a new study shows that vulturine guinea fowl, a bird with distinctive blue plumage that lives in Africa, can keep track of relationships with hundreds of others -- challenging the prevailing view that big brains are a requirement for complex society.
While many birds live in groups, these birds behave "highly cohesively" and don't display any aggression between groups.
"To our knowledge, this is the first time a social structure like this has been described for birds," said Danai Papageorgiou, lead author of the paper published Monday in Current Biology and a PhD student at the Max Planck Institute of Animal Behavior in Germany.
Groups of vulturine guinea fowl can become very large, and when multiple groups come into contact the number of birds moving together can reach into the hundreds. However, when these 'super-groups' eventually split, they do so back into their original stable group units, meaning that individuals are knowledgeable about who is part of their group and who is not.
"It is remarkable to observe hundreds of birds coming out of a roost and splitting up perfectly into completely stable groups every single day."
The study, which is the first conducted on the species, involved tracking social relationships in a population of more than 400 adult birds in Kenya for 12 months. Tracking the vulturine guinea fowl took place at the Mpala Research Centre and Wildlife Foundation in Laikipia District, central Kenya. The researchers individually marked all birds in the population. By observing them they discovered that the population comprised 18 distinct social groups, with 13 to 65 birds in each group.
The researchers witnessed the birds walking very long distances -- up to 15 kilometers a day --- remaini