As we all know, people have personalities. The personality of a person influences the way he or she interacts with other people. Animals also differ in the way they interact with other animals. As people who have pets might recognize, some pets are shy, others are bold. Scientists are increasingly aware of the fact that also animals differ in their personality. However, it remains difficult to quantify the personality of an animal. In the great tit (Parus major), scientists have devised methods to assess the personality of an animal. This provides insight into how animals with different personalities cope with certain situations. But how do you measure the personality of a bird?
In great tits, personality is measured as exploration score. This means that birds that quickly explore new unfamiliar surroundings have a different personality than birds that do not explore quickly. This is measured this by introducing a bird to a chamber which contains 5 artificial trees (for pictures look here). During the first 2 minutes in this unfamiliar room all movements are tracked and used as a proxy for their personality. Birds with a low score did not move much and are generally seen as shy individuals. Birds with high scores moved a lot and visited all the artificial trees, they are seen as bold individuals and tend to be more aggressive towards other great tits.
The personality scores from the laboratory are nice, but what does this mean for the interaction between different males in the field? We looked at males because they are the ones defending the territory. We wanted to see whether there is a relation between the differences in personality that are measured in the lab and the way they interact with other males in the field. To do this, we first measured the personality score in many birds in the lab. We released these birds again in the field. During the spring of 2008 we tested how they responded to an unfamiliar male in their territory. We did this by playing the song of a great tit through a speaker. We scored the response of the bird and related this to its personality. The song of great tits consists of several notes (number 3 in the figure below), which are repeated in a strophe (1). Every bird is able to sing several different songs (A, B, C). We expected that shy birds would stay further away from the speaker and respond by singing while bold birds would come close for an all-out brawl to physically remove that other bird from their territory. What we found was unexpected.
Jacobs CGC, van Overveld T, Careau V, Matthysen E, Adriaensen F, Slabbekoorn H:
Personality dependent response to field playback in great tits: slow explorers can be strong responders. Animal Behaviour 2014, 90(0):65-71.