Shy Great Tits flock together

According to a study published in Ecology Letters, shy Great Tits prefer the company of fellow introverts. Researchers associated with the Edward Grey Institute of Field Ornithology at the University of Oxford studied the birds in Wytham Woods, near Oxford, to determine how personality affects social behaviour. The abstract of the paper is as follows:

Social environments have an important effect on a range of ecological processes, and form a crucial component of selection. However, little is known of the link between personality, social behaviour and population structure. We combine a well-understood personality trait with large-scale social networks in wild songbirds, and show that personality underpins multiple aspects of social organisation. First, we demonstrate a relationship between network centrality and personality with 'proactive' (fast-exploring) individuals associating weakly with greater numbers of conspecifics and moving between flocks. Second, temporal stability of associations relates to personality: 'reactive' (slow-exploring) birds form synergistically stable relationships. Finally, we show that personality influences social structure, with males non-randomly distributed across groups. These results provide strong evidence that songbirds follow alternative social strategies related to personality. This has implications not only for the causes of social network structure but also for the strength and direction of selection on personality in natural populations.

Previous research found evidence that birds with larger social networks can find more food, with the advantage going to individuals more apt to mingle. The intersection of personality and social behaviour is a new and growing area of study in biology and behavioural ecology, and study co-author Julie Morand-Ferron explained: "If you take the simple definition of personality as behaving consistently over time, then you can find personality traits in vertebrates and insects and all sorts of animals."

For the purposes of this study, shy or 'reactive' birds are slower to explore and less likely to take risks. Bold or 'proactive' birds prefer high risks and high rewards. Researchers first needed to determine which Great Tits were shy, and which were bold. To test this, 221 birds were captured and released, one by one, into a room containing five artificial trees. The scientists then recorded their movements. Morand-Ferron commented: "The very shy birds basically don't move that much. They seem to be very careful. They hop from tree to tree, or they fly a bit. Bolder birds, on the other hand, have a very high activity rate. They land on the ground. They fly quickly."

Following determination of the personality of each tit, the researchers released them back into the wild, where they tracked their movements. The Great Tits of Wytham Woods have been studied for more than six decades, and most of them wear plastic rings containing transponders around their legs. Sensors on the 65 feeding stations dotting the forest pick up the transponder signals whenever the birds come close enough. Over the winter months, when the species congregates in loose flocks, the researchers monitored where the tested birds were feeding and who they were associating with.

Great Tit, undisclosed site, Norfolk (Photo: Matt Crosby)

They discovered that male birds who exhibited shy behaviour in captivity tended to stay in flocks with their shy friends in the wild for longer periods of time, while the bolder birds flitted from flock to flock. In a previous paper, the authors determined that birds with larger social networks — like those bold birds — find out about hidden sources of food quickly because they have access to more information. But they're not sure yet what evolutionary advantage shy males might gain from sticking together. In the paper, the authors hypothesize that the shy males are trying to avoid the more aggressive bold males, but Morand-Ferron emphasizes that this is a question for further study.