The old adage "birds of a feather flock together" takes on a whole new meaning with new research published in the journal Ecology Letters, which contends that male birds with "shy" social behavior are more likely to join flocks of birds with similar personalities.
Great tits (Parus major) that exhibit shy behavior tend to flock together more than their counterparts with more bold personalities, researchers report, adding that the shy birds also tend to have fewer social partners in general when compared to more outgoing bids of the same species.
The great tit is one of the most well-studied birds in the world, with more than 60 years of research already done on the creature. In this study, researchers from Oxford University and the Australian National University analyzed the social network the great tits form to see how the birds are linked to one another.
The analysis revealed that differences among individual birds underpinned the way the great tits interact socially across the greater population.
"There has been a lot of work describing the range of individual personalities in the great tit," said the study's lead author Lucy Aplin, from Oxford University and the ANU Research School of Biology."Now we are linking it to the social networks and social organization of the species, which hasn't been done before."
To construct the great tit's social network, the researchers analyzed bird feeders which were set up to record the presence of thousands of the birds which have been fitted with tracking bands.
Millions of feeder visits made by birds over an entire winter were recorded to reconstruct the social network -- meaning the pattern of with whom an individual interacts and how often -- across an entire population.
Great tits were graded on a personality axis ranging from shy to bold.
The birds' personality was tested by introducing them to new environments and seeing how they would react -- "typically 'shy' birds would explore the strange environment very slowly whereas 'bold' ones moved quickly to explore it," the researchers wrote in a statement.
"The tests were repeated over time and the responses of individuals proved to be, surprisingly, very consistent so that they could be attributed a personality somewhere along the shy/bold spectrum."
The team also tracked how the birds interacted with other birds to assess how their personality might influence social behavior.
"Bold birds went for quantity over quality in their relationships, having weaker associations with more birds and foraging with several different groups," the researchers said.
Alpin said that by measuring the birds' social networks, it was clear that bolder birds tended to jump between foraging flocks and only forged short term associations, while the shy birds tended to maintain foraging associations over a long time.
The researchers attributed the difference in behaviors to the birds' differences in risk response -- shy birds tend to engage in low risk/low reward behavior, whereas their bolder counterparts engage in high risk/high reward behavior, the researchers said.
"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," Alpin said.
"We think shy male birds might group together to avoid the more aggressive bold birds," said Aplin, who added that this trend was only seen in males.
Female great tits seemed to associate freely with all personalities.
"Understanding how personality is related to social network structure, in turn helps us to understand how personality and sociality evolved. We are exploring how a range of alternative social strategies could coexist in the one population," Alpin added.