Birds express their personalities through song

Hidden in the bushes of South Australia, a tiny bird is singing. But its voice carries more than a melody. In the superb fairy-wren, song is not just for romance or rivalry. It may also reveal something deeper – personality.

Birdsong has long fascinated biologists. It’s central to mating and territory defense. It can also hint at an individual’s condition or cognitive skill.

But one question remained mostly untouched: can song reflect personality traits, especially in female birds? A new study answers that with a confident yes.

Researchers from Flinders University set out to explore this in wild superb fairy-wrens, a species where both sexes sing.

The results, published in Royal Society Open Science, reveal how personality traits like exploration and aggressiveness influence the complexity of bird song. And it’s not just males that sing with meaning.

Why bird personality matters

In animal behavior research, personality refers to consistent differences in behavior across time and situations. Some birds are bold, while some are shy. Some explore widely, yet others stay safe. These traits affect how animals survive, mate, and interact with the world.

Dr Diane Colombelli-Négrel and her team studied two key personality traits: exploration and aggressiveness. These have ecological relevance.

Exploratory birds are often more curious and likely to investigate unfamiliar environments. Aggressive birds may confront rivals and defend territory more strongly.

Previous studies hinted at links between personality and signaling, especially in males. But no one had tested how these links play out in both sexes – or how they affect learned traits such as song complexity. This made superb fairy-wrens, where both males and females sing, a perfect subject.

Fairy-wrens learn songs throughout life

Superb fairy-wrens are insectivorous songbirds native to southeastern Australia. They live in social groups, often with a breeding pair and several helpers.

These birds sing complex “chatter songs” that serve both mating and defensive purposes. Juveniles start singing full songs about 50 days after fledging.

Song learning starts early, even in the egg. Birds learn from their parents and others nearby. Adults may continue learning, suggesting they are open-ended learners.

“Regardless of their sex or life stage, individuals that were more exploratory had more element types per song, which may be explained by the possibility that more exploratory birds approach and learn from a wider variety of tutors compared to less exploratory birds,” said Dr Colombelli-Négrel.

Song style linked to bird personality

Between 2019 and 2023, researchers captured 102 color-banded birds – 62 males and 40 females – at Cleland Wildlife Park. Each bird went through two personality tests while in short-term captivity.

To measure exploration, they placed each bird in a novel environment – a flight cage divided into sectors. The more sectors a bird visited in five minutes, the more exploratory it was.

To measure aggressiveness, they used a mirror test. Birds that spent more time near their reflection were considered more aggressive.

The researchers then released the birds back into their territory. Over several months, the team recorded 1,034 chatter songs.

They analyzed these for complexity – counting the number of unique element types, rare elements, and syllables. The experts also compared song traits between adults and fledglings.

Exploration increases song complexity

Exploratory birds had more element types per song. This finding held true regardless of sex or life stage.

The research indicates that curious individuals are exposed to more vocal tutors. They hear a wider variety of song elements and may include these in their own songs.

More exploratory individuals also had more rare element types. This suggests a broader learning scope. They don’t just copy common tunes – they gather and use the unusual ones too.

Interestingly, the number of songs recorded also predicted element diversity. This supports the idea that superb fairy-wren songs are highly variable and change with context.

Bold birds sing fewer syllables

More aggressive individuals produced songs with fewer syllables. Aggressive fledglings, but not adults, had more element types per song. In birds, singing behaviors – shaped in part by personality – play a critical role in mating and territory defense.

This pattern reveals something about the trade-offs in song structure. More aggressive individuals, perhaps focused on signaling dominance or defending space, may prioritize efficiency over complexity.

Their songs are shorter but still effective. In fledglings, however, aggression coincided with more varied element types.

One possibility is that these young birds experiment more to assert dominance. Adults, already established in their roles, may have less need to vary their songs.

Do males and females sing differently?

The study revealed that females sang songs with more syllables than males, regardless of their personalities. This contrasts with earlier findings in some fairy-wren populations.

Despite singing differently, males and females did not differ in exploration or aggression scores. Both sexes showed similar consistency in personality traits, and both advertised those traits through song.

“Our study supports the idea that both male and female birds can advertise their personality when singing, which may be important for mate choice,” said Dr Colombelli-Négrel.

Bird songs, personality, and mating

The research adds weight to the idea that birdsong carries more than just mating or territorial messages. It may also serve as an honest signal of behavioral type.

More exploratory birds might signal adaptability. They may be preferred by mates for their diverse repertoires. Aggressive birds might use simpler, more direct songs to assert control or deter rivals.

Whether these song traits influence reproductive success in superb fairy-wrens remains to be tested. But in other species, females do prefer songs linked to cognitive or exploratory traits.

Singing might show intelligence

If personality shapes song learning, then vocal signals may help listeners judge a potential mate’s behavior – even before meeting them. A song could hint at curiosity, social habits, or risk-taking style.

In species like the zebra finch, females preferred the songs of males who solved problems faster. If similar dynamics exist in fairy-wrens, song may be an indicator of intelligence or flexibility.

The link between personality and song complexity may also affect social learning. More sociable fledglings might pick up more element types simply by being around more tutors.

Birds sing to express themselves

The superb fairy-wren’s chatter song is more than a call. It is a self-portrait painted with sound. This study shows that personality shapes that portrait, adding complexity or simplicity depending on the individual.

By examining both sexes and different life stages, the researchers have uncovered how traits like curiosity and boldness echo through the air.

The findings open new questions about how birds learn, express themselves, and choose mates. In these tiny birds, personality doesn’t just fly – it sings.

The study is published in the journal Royal Society Open Science.

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