New research from the University of Oxford and the Australian National University suggests that birds choose their friends not by instinct, but by personality. Shy birds are more likely to have few close friends, while bold birds have more friends yet less stable relationships overall.
Perhaps birds of a feather really do flock together.
In the latest study on great tits (Parus major), researchers observed the birds in the woods near Oxford, and found that both shy male and female tits did not interact with as many individuals as their bolder counterparts did, but were more likely to have stable relationships with other birds, as they spent more time with the same individuals in comparison to their more outgoing peers.
"Our aim in this project has been to understand why individuals differ in their social behavior, and ultimately what consequences this has. We're increasingly realizing that processes in wild populations depend in many ways on how individuals interact with each other," Professor Ben Sheldon, Director of the Edward Grey Institute at Oxford University's Department of Zoology, and an author of the report, said in a press release.
Lucy Aplin, a DPhil student with Oxford University and the ANU Research School of Biology, explained that there has been a lot of research going into the individual personalities of great tits. "Now we are linking it to the social networks and social organisation of the species, which hasn't been done before," she said.
In order to test the personalities of the birds, the researchers introduced individuals to new environments and studied how they reacted. "Shy" birds were more likely to explore the strange environment slowly, while "bold" birds were quick to investigate their unfamiliar surroundings. The tits were rated on a personality axis ranging from shy to bold, and the tests were repeated over time to make sure the tits' responses were consistent.
"Measuring the social networks we could see that bolder birds tended to hop between foraging flocks and have short term foraging associations, while shy birds tended to maintain a foraging association over a long time," said Aplin. "Shy birds are following a social strategy where they maintain a few strong and stable social associations to minimize risk. Hopping between many flocks may increase risks for bolder birds, but might maximize rewards through improving their social position and giving them better access to information, such as the location of food."
Shy and bold birds were also more likely to interact with those whose personalities were similar to theirs.
A report on the new research will be published in the journal Ecology this week.
