Game of Nests

Based on the success of House of Cards and other political dramas, it’s no secret: humans love their politics. But is it for the birds as well? In a new study published in Current Biology, researchers at the University of Vienna have found that ravens play politics too.

Ravens are social creatures, travelling in flocks with dynamic social structures.  Within a flock there are kinship bonds, but there are also male-female bonds with varying degrees of strength. Pair bonds between established breeding pairs are the most powerful, while the bond between breeding ravens without established territory is weaker. Loosely bonded pairs are ‘dating’ so to speak- still in the process of establishing a bond, while some ravens fly solo, remaining unbonded. 

In the raven world, the strength of a bond is related to dominance in the flock: the stronger the bond, the stronger the alliance, and the greater the rank within raven hierarchy. Not only do ravens remember these alliances for years, but remarkably, they follow the dominance ranks between other individuals.

So what does a raven bond look like?  Bonds are both created and maintained through what researchers call affiliative behaviours.  Sitting side by side, feather preening, touching beaks, or playing with objects together all help form and maintain bonds. Over time as the bond deepens, these interactions become more intense, more reciprocal, and an alliance develops.

Forming strong alliances is one surefire way to raise your stature in the raven hierarchy. But are there other strategic ways to ensure power? This was the question posed by researchers at the University of Vienna, in Austria. When researchers studied the behaviours of a population of wild ravens, they found that about 20% of the time a raven will try to interrupt the alliance-building behaviours of other ravens. And about half of the time, that raven is successful.
As you can imagine, interrupting a pair of happily grooming/playing ravens does not always go well. A raven risks starting a fight-with the potential to be outnumbered-when it puts its beak where its not wanted. That’s why ravens are very strategic when it comes to the type of alliances they target.

Researchers found that interrupting ravens largely ignored ravens without alliances, likely because they aren’t considered much of a threat. And ravens were not likely to discourage the bonding behaviours of ravens with strong alliances because, the authors conclude, it’s not worth the cost to try and break up a well-established alliance.  But those ravens that are just ‘dating’ –without an established bond– are an ideal target. Preventing a potential future alliance may be the best way for a raven to ensure its current dominance. Overall, ravens with the strongest alliances were most likely to intervene in alliance-building behaviours.

What is remarkable is that throughout the 6 month study, the authors never once saw an immediate benefit, such as food, territory, or breeding partners, for the interrupting raven. This suggests that the ravens are in it for the long-term benefits, and truly are playing politics. Who knows? Maybe you've encountered the Frank and Claire Underwood of the raven world on your morning commute.