Game Theory Predicts Never Before Documented Raven Behavior
When I think of ravens, I am quick to imagine a dark scene out of Edgar Allan Poe’s work that parallels ravens’ real-life habit of eating from carcasses. However, these dark-feathered birds also have brights minds. They have been known to bring befriended humans gifts and can mimic sounds in as many as 33 vocal categories (Sewall, 2015; Lab of Ornithology, 2001). If that weren’t enough, scientists from the University of Exeter discovered a never-before-documented raven behavior. They found that some young ravens hunt in groups as large as 30 instead of the common alternative strategy of hunting alone. Typically, after a lonesome hunt, ravens will defend a carcass with a partner. In these large gangs, however, they hunt as a pack and temporarily displace adult pairs from carcasses they were guarding, giving this partnered pair first-hand experience as to why a group of ravens is known as unkindness (Walker, 2015). The researchers discovered this by placing sheep cadavers with colored beads placed inside at different distances from a ravens’ communal roost. The ravens would later regurgitate these beads in the roost, which showed the researchers that ravens who lived in the same roost ate from the same carcasses.
This study relates to class as game theory models were used to predict this behavior before this discovery. Using these models, the researchers learned that two strategies should occur. An individual exploration strategy would be most beneficial for obtaining food far away from their roost, while a gang strategy would be more optimal for areas where food is close to the roost. This is likely because flying individually allows a group to cover more area, while flying together allows for quicker access to food when food is consistently nearby. Given that the studied raven population was in an agricultural region, it makes sense that this predicted gang strategy would appear in real life. Additionally, under both strategies, these ravens would belong to different forms of social networks. In the individual strategy, their network is smaller with weaker ties, which means a decreased likelihood of finding food, but they would get a higher amount of food from each carcass. The inverse would be true in the gang strategy, which has stronger ties in a more extensive social network. Not only that, but the gang strategy allows for greater mobility of social ranking. This provides an excellent example of how networks and game theory can influence one another. Nevermore will I think of ravens the same again.
Author: Jessica Lecorchick
Main References:
- Raven teenager gangs play by game theory (phys.org)
- Bizarre Bird Behavior Predicted By Game Theory — ScienceDaily
Additional References:
- The girl who gets gifts from birds – BBC News
- Common Raven Sounds, All About Birds, Cornell Lab of Ornithology
- What do you call a group of ravens? | Global Ideas | DW | 28.01.2015