Superb fairy-wrens’ songs hold clues to their personalities, new study finds
- Written by The Conversation
When we think of bird songs, we often imagine a cheerful soundtrack during our morning walks. However, for birds, songs are much more than background music – they are crucial to attract a mate and defend a territory.
But what if a song could reveal something deeper about the singer’s personality? A new study, published today in Royal Society Open Science by my colleagues and me, shows it might.
Addressing a research gap
For many bird species, songs vary in complexity, with some individuals producing more intricate melodies than others. Such differences often indicate individual variation in genetic quality, age, or health. Yet most research to date has focused on males, and very few studies have investigated how song complexity relates to personality in birds.
The new study addresses this research gap.
My colleagues and I studied wild superb fairy-wrens (Malurus cyaneus), a small Australian songbird known for its bright plumage and complex vocal skills. Interestingly, in this species, both males and females learn to sing complex songs. This makes them a good example to study the relationship between song complexity and personality in both males and females.
We captured wild superb fairy-wrens and brought them into short-term captivity to assess their personality. Specifically, we measured their exploration by placing them in a novel environment, where we observed where they went and how much they explored the environment.
We also tested their aggressiveness by using a mirror, as birds often see their reflection as a rival and respond accordingly.
We then released the birds and recorded their songs for several months to assess song complexity (that is, element types per song and syllables per song). Elements are the basic building blocks in bird songs (a little like letters in a word) and element types are categories of elements.
Aggressive versus exploratory
We found that, regardless of sex or life stage, birds that were more exploratory had more element types per song than those that were less exploratory. Also, more aggressive birds produced songs with fewer syllables than those that were less aggressive. You can hear this in the recordings below.
We also found that more aggressive fledglings, but not adults, had more element types per song.
Our study demonstrates that both males and females can advertise their personality through their songs. It also raises questions as to whom birds learn their songs from.
In superb fairy-wrens, male and female juveniles learn from both parents as well as from other members of their species. It is possible that rather than learning from any available adults, birds may selectively copy song elements from specific individuals based on their own personality.
In superb fairy-wrens, more exploratory birds may approach and learn from a wider range of tutors than less exploratory ones who may limit themselves to more familiar tutors.
Additionally, our study highlights that the relationship between personality and song complexity could be shifting between different life stages. More aggressive young may experiment with a greater diversity of element types to prepare for the establishment of their own territory in their first year of life, leading to increasing song complexity.
In contrast, adults have already settled in their territories and may not need to experiment as much.
Insights into how personality traits evolve
Our study illustrates that learned aspects of sexual signalling are personality dependent, and that this may have some potential implications for survival or reproduction.
This opens up exciting new questions about how vocal communication reflects individual differences — not just in males, but in females too.
Understanding these links can give us deeper insights into how personality traits evolve and how they influence social interactions in the wild.
