Shy male birds keep closer 'friends'
Shy male great tits have fewer 'friends' but build stronger bonds than bolder birds, researchers have found.
Scientists have studied the birds in Oxfordshire for over 60 years and their latest results revealed how personality affects behaviour.
To understand the intricacies of their social networks, the birds' woodland movements were tracked using tiny tags.
Shyer birds were found to be more likely to stay in the same flock while bolder birds were more gregarious.
The results are published in the journal Ecology Letters.
Scientists have been studying a population of around 1,000 great tits at Wytham Woods since 1947.
"Great tits are one of the best studied species of bird in the world and Oxford has led the way in this," said Lucy Aplin from Oxford University and the Australian National University, who was the lead author of the study.
"That's usually been done through breeding season surveys - monitoring their reproductive success - but in the last ten years we've been able to start looking at their winter behaviour."
The birds have unique PIT tags - similar to those used for identifying pets - carried inside a ring placed around one leg so researchers can identify individuals.
The birds' personalities were also profiled in a "novel environment" experiment that required them to be caught temporarily and introduced to a room for 10 minutes with a series of perches that they had not experienced before.
In a series of experiments over four winters, birds that investigated these environments slowly were placed on the "shy" end of the scale while those quick to explore were deemed bolder.
Once the birds were released, the team were able to track their movements around the woods via the tags and 65 specially installed feeder stations.
As well as providing food through the winter, the stations were equipped with radio transmitters that logged whenever a tagged bird visited.
"Social behaviour's been really hard to study in the past as I'm sure you can imagine," said Ms Aplin describing the history of difficulties of following flocks of birds.
"So this new technology has really allowed us to do it... We can measure the spatial temporal flocking patterns without having to put binoculars to eyes."Birds of a feather
Previous studies have shown that the birds form "fission-fusion" groups during winter foraging. The description comes from how social bonds are broken and forged.
Ms Aplin and the team analysed the data from the woods and discovered that shy birds flocked together.
"Shyer birds tend to have much more stable associations that are stronger and persist over a long period of time but there are less of them," she explained.
In comparison, bold birds opted for quantity rather than quality: foraging with several different groups and having more short-term associations with a greater number of birds.
"Males tend to prefer to associate with individuals with the same personality type as them and we think this might be to do with shy birds avoiding bold males," suggested Ms Aplin.
"We know that boldness is associated with aggressiveness and males tend to fight more than females do in great tits."
The team will continue their research into understanding what consequences can be linked to different personalities and social behaviours in the birds.
"This research is really interested in trying to understand the social structure of great tit populations and their dynamics and social relationships in winter flocks," Ms Aplin said.
"By doing this we hope to understand not only their social behaviour but how their social structure affects the spread of disease or the spread of information."