To tweet or not to tweet : the role of personality in the social networks of great tits: the role of personality in the social networks of great tits

To tweet or not to tweet: The role of personality in the social networks of great tits
By: Lysanne Snijders

Project video: https://www.youtube.com/watch?v=zy0HysxhQz0

When mentioning social networks it is easy to think of online networks for people, such as Facebook and Twitter. But many animals also have social networks. In proximity networks they encounter each other physically and in communication networks they connect to each other by using signals. Their position in such social networks is important. It can influence the likelihood of finding new food, acquiring novel foraging techniques, rising in social status and acquiring a mate. However, having many contacts can also be risky as it increases the likelihood of encountering infectious diseases, social stress or ending up in a fight.            
                As social network position can be so significant, it is essential that we know what determines it. A likely key factor is personality. Individuals consistently differ in how risk-prone (pro-active) and risk-averse (re-active) they tend to behave. As making face-to-face contact is not without risk, bolder individuals might have more social contacts.

An ideal model to study this hypothesis is the great tit. A common garden bird. There are well established methods to quantify personality differences in great tits and with the newest tracking technologies we can now also monitor their face-tot-face contacts. What makes the great tit even more interesting is that they like to breed in nest boxes and so we can also study potential fitness effects of specific network positions. Additionally, great tits are songbirds, which makes them also ideal to answer a second question: Do individuals that are shy to approach others, use communication instead? Since communication is often a less risky connection strategy than face-to-face contact.

In this PhD thesis I reveal how and when personality explains why some birds are better connected than others. In wild territorial populations pro-active males were better connected to other males and were most likely to approach a rival. In contrast, when removing the risk of fights during male-to-male spatial associations, via a video-playback experiment in captivity, the re-active males appeared to be most social. When confronted with the life-size video image of a novel conspecific, they spent the most time associating with it. When lowering the risks associated with spatial associations the social preferences of re-active individuals might thus increase. No relationship was found between social network position in the wild and reproductive success, an important fitness component. 
                Wild male great tits that were less likely to approach a rival, sang more actively at dawn. Dawn song is the peak time for male great tit singing activity and operates as a large communication network.  Since a prime function of singing at dawn is territory advertisement, these birds might thus try to prevent rival territory intrusions by singing more fiercely at dawn. No direct links were found between personality and an individual’s place in the communication network, however pro-active birds vocalized most actively during territory intrusions and increased their singing activity significantly during the fertile period of their mate.          
                Communication networks and proximity networks can influence each other via song, by attracting or repulsing conspecifics to come close. For example, the vocal response of an intruded male to its rival significantly influenced whether female neighbours would come close to the intrusion site and if male neighbours would stay away.       

What determines the place in a social network? By knowing this we learn more about how groups function and how different social strategies in the same population can co-exist.