This is a guest post by Amy LeBlanc.
It is a cold morning in rural Victoria, the mists still clinging to the grass in the paddocks. The euphonious sound of birdsong is all around, filling the air with both harmonies and clashing notes. A nearby bush rustles and out of it bursts a woman covered in twigs and leaves. She is holding a big fluffy microphone and has a heavy pair of binoculars around her neck. This is Amy LeBlanc, a researcher from the University of Melbourne, and she is here to chase down one of the cuter members of the dawn chorus: the superb fairy-wren.
Superb fairy-wrens are a favourite fixture throughout the south-eastern corner of mainland Australia and Tasmania, where they can be found in a large range of habitats. Although the females are a subtle brown colour, the eye-catching blue plumage of the males has made these birds something of an avian celebrity; images of fairy-wrens appear on everything from postcards to teacups, and they are well recognised by the general public. Their pretty plumage and coquettish tail flicks, coupled with the bird’s propensity to approach people, makes this species a popular backyard bird. What the public might not know is that this sweet little tweeter has a rather sordid private life.
It has been known for quite some time that female and male wrens form lifelong partnerships where they defend a small territory and help to raise chicks together. Fairy-wrens have an interesting form of brood-care called cooperative breeding, where older sons will stay on with their mother at the nest and help raise younger generations of siblings. However, as it turns out, this happy little household holds quite a few secrets, and the family life of a wren is not as clean-cut as had previously been assumed.
In 1994, a study by Raoul Mulder showed that the large majority of eggs in a fairy-wren nest weren’t actually fathered by the dominant male of that territory. In other words, although the male and female were socially bonded, about 61-76% of the chicks he helped raise weren’t actually his. As it turns out, superb fairy-wrens have an extraordinarily high level of extra-pair paternity, where the female mates with males other than her social partner.
With this interesting mating system in mind, a long-term study was initiated at Serendip Sanctuary in Victoria to study a population of these unconventional songbirds. The study focused on personality and behaviour in the wrens. Each individual in the wildlife sanctuary was banded with a unique combination of colour bands, and over the course of the following decade extensive information has been collected on each Serendip bird.
It is this study that LeBlanc joined in 2015. Her specialisation is in animal communication, particularly the study of song complexity in passerine birds. Songbirds have long been thought to exhibit one of the most complex forms of audio communication know to science. Not only do their trills and warbles sound pretty, they are also able to convey an astounding amount of information from one bird to another.
Just as a human sentence is composed of words, syllables and phonemes all bound together by grammar, a bird song has phrases, syllables and elements bound together by syntax. And like a character out of a Shakespeare play, birds with larger vocabularies, or repertoires, are found to be more attractive by their peers than those who only know a few basic songs.
By recording the songs of superb fairy-wrens, LeBlanc is hoping to measure the repertoire sizes in different fairy-wrens and then compare their song complexity to traits such as sex, age and personality. She has also conducted experiments where she manipulated song recordings into complex and simple versions of the same song, played them to the wild wrens and recorded their reactions to each song type. Safe to say, the birds weren’t happy with the recordings: they were the equivalent of a stranger coming into your kitchen and belting out an opera. The level of reaction displayed by the birds in response to this intrusion can, however, tell us a lot about how they deal with conflict. LeBlanc is hoping to see if birds with different personalities react differently to her rude song intrusions.
What she has found so far is that males and females have similar repertoire sizes. However, male birds tend to cram more syllable types into each song than females. In other words, although they know a similar number of syllables, or “words”, the males choose to use more per song than the females. Unlike their female companions, they are a bit “wordier” with their lyrics. The results are preliminary and there is more yet to be explored, but what they show so far are some interesting similarities and differences between male and female birds.
Superb fairy-wrens, those sweet Australian songsters, have a lot more going on in their lives than simply showing off their feathers. From lifetime loves, to sordid neighbourhood affairs and complex sonatas, these birds demonstrate just how intriguing the social lives of our native animals can be. Through research and long-term studies, we can uncover all kinds of hidden facts about even our most common backyard birds.
Amy LeBlanc is a MSc candidate at the University of Melbourne, studying animal communication. She is passionate about science communication and anything with feathers.
You can find her on twitter @amylebird.
Banner image courtesy of Timon van Asten.