A recent study on social bird behavior has found that more sociality in birds may confer to reduced competition in interactions between and among bird species. The findings, published on March 1 in The Proceedings of the Royal Society B, utilized data from the Cornell Lab of Ornithology.
Sociality, or the degree to which individuals interact and associate in groups, is a highly favorable trait for many species because it enhances reproductive opportunities, improves foraging results and provides protection from predators. In addition to these benefits, the study notes that sociality also influences bird dominance hierarchies, in which larger birds tend to overpower smaller ones.
“There are some obvious benefits to being a social species,” said co-author Eliot Miller, a postdoctoral associate at the Lab. “Birds that aren’t that good at these interspecific interactions tend to lose when they’re alone, and they do better when they’re in groups.”
While doing research in Ecuador before graduate school, Miller developed an interest in the evolutionary and ecological ramifications of social interactions between birds. He encountered difficulties obtaining adequate sample sizes for his research, which prompted him to partner with citizen scientists to help contribute data.
In 2016, Miller helped create Project FeederWatch — a website that allows people to send in videos and data tracking bird presence and behavior in their area. Through this project, Miller and his colleagues were able to utilize data from over 55,000 interactions among 68 common species to make conclusions about social bird behavior.
“We’re measuring sociality by the group size that people saw on their feeders,” Miller said.
The most notable pattern in the interaction data showed that larger birds tend to physically attach smaller birds. The researchers also found that if organisms of social species must survive on their own, they tend to be less dominant than expected for their body mass.
“Against an equally-matched competitor that doesn’t tend to be social, the social species will more often lose in that one-on-one encounter, but when they show up in groups at feeders, the social species tend to have an advantage and more confidence… they’ve got their friends with them,” Miller said.
The decision to be social or solitary and the selective pressures that drive sociality — as well as the effects of diet and disease on sociality and avian communities — are topics that Miller intends to further explore utilizing the data from this research.
“Data sets are growing and there’s a lot of smart people out there in the world, so I think this [research] could go any number of really fun ways from here,” Miller said. “I’m always thankful for all of the citizen scientists that submit all their great data.”
Anna Labiner is a staff writer for the science department and can be reached at [email protected]