Many animals are social, but only a few have what biologists refer to as “complex” or “multilevel” societies. These have been thought to exist only among mammals, and larger-brained species at that, so it was a shock for scientists to discover a multilevel society among vulturine guineafowl, an African bird not exactly known for its intelligence.
For animals, complex societies are those where individuals are part of stable groups, which in turn fit within larger networks. This requires the capacity to recognize individuals not part of an animal’s immediate pack or tribe, and remember the relationship status.
When it was recently discovered western gorillas have complex societies the finding was unexpected because scientists had extrapolated a little too heavily from chimpanzee studies, where every chimp outside the troop is considered hostile. Nevertheless, it’s not hard to believe our big-brained cousins could keep track of individuals in other groups to know friend from foe, as dolphins, for example, do.
On the other hand, guineafowl can seem too stupid to maintain more than a simple pecking order. However, Danai Papageorgiou, a PhD student at the Max Planck Institute of Animal Behavior, observed 400 adult vulturine guineafowl in the wild in Kenya.
In Current Biology Papageorgiou and co-authors report the birds formed 18 social groups with 13-65 members each. The groups inhabited overlapping territories, without getting into the battles for land that make some other birds appear to be operating their own private Westeros.
Instead, some groups came together with others more than could be attributed to chance, indicating a collective preference for spending time together.
"To our knowledge, this is the first time a social structure like this has been described for birds," Papageorgiou said in a statement. "It is remarkable to observe hundreds of birds coming out of a roost and splitting up perfectly into completely stable groups every single day. How do they do that? It's obviously not just about being smart."
Dr Damien Farine, the paper’s senior author, added: “[The finding] has opened up exciting possibilities of exploring what is it about this bird that has made them evolve a social system that is in many ways more comparable to a primate than to other birds."
Improvements in cameras and tracking devices have allowed scientists to observe social dynamics in animals in the wild in ways that were impossible until recently, greatly expanding our knowledge of social networks. Indeed, a paper published days before Papageorgiou's reveals social networking can occur even between members of apparently competing species, particularly at low population densities. For example, wildebeest and zebra may both want the same food and water, but can co-operate when it comes to looking out for lions.