3 reasons why the superb fairy-wren is your new favourite bird

As a Masters student, I’ve signed away two years of my life to study birds.

Now ‒ don’t get me wrong ‒ I love my work, but friends and colleagues have occasionally raised an eyebrow at my choice of study species. After all, what does it say about me when my favourite bird looks like he was dressed by Cirque du Soleil?

Not that there’s anything wrong with that. Source: Own work

The superb fairy-wren has always been saddled with such prejudice. Hell, they even named it a fairy-wren, as though to suck out every particle of manliness from its public persona.

And that’s where I come in, determined to set the record straight. On behalf of superb fairy-wrens everywhere, here are three reasons why they are the most awesome of avians, and worthy of interest by even the manliest of men.

#1 They commit adultery like nobody else

OK, so we’re not starting with the most noble of character traits, but everybody loves a bit of erotic intrigue.

Superb fairy-wrens are socially monogamous, meaning that, like us, they pair up for years at a time. From that point onwards, they seemingly live out the perfect romance: always as a couple, they defend a home territory and lovingly raise generations of chicks from egg to adulthood. Sound like the perfect relationship?

But looks can be deceiving. Source: Wikimedia Commons

In the 1990s, scientists took a closer look at those chicks. And, shock and horror, most of the time they were related to the mother but not to her partner. The actual father was some other male in a neighbouring territory.

You see, superb fairy-wrens are ludicrously unfaithful partners. Males spend a significant part of their day energetically displaying to prospective females, and occasionally wooing them with yellow flower petals, because they’re classier than you are. And, if she likes what she sees, she will sneak off at dawn to consummate their illicit romance. A bit like Anna Karenina.

That’s my educated literary reference for the week. Source: Wikimedia Commons

This sort of behaviour is actually extremely common in the bird kingdom, with 90% of supposedly “monogamous” species unfaithful to some degree. We think there must be some sort of advantage to this: a female receives the benefit of having a useful husband around the house, but also gets to choose the fittest or most compatible male to father her children.

Other bird species may also be unfaithful, but when it comes to philandering, nobody does it quite like the superb fairy-wren. According to one study, three-quarters of all chicks are the products of infidelity. That’s not just the occasional indiscretion; fairy-wrens have adopted adultery as a life-style choice.

#2 They sing in the face of their nemesis

Fairy-wrens are delicious to eat. I don’t know this from experience, but there are quite a few predators who would love nothing more than to chow down on your new favourite bird.

Among the most dangerous of these predators is the butcherbird, a relative of the magpie. Like some maniacal horror villain, the butcherbird will routinely impale its prey on thorns and branches, because apparently female butcherbirds find that impressive.

So, if you were a fairy-wren, you would be forgiven for taking cover every time a butcherbird sails overhead. Except that’s not what happens ‒ the male fairy-wren doesn’t take cover.

He starts singing.

DSC_0225 (2)
Image source: Own work.

This isn’t a warning call or anything; it’s a genuine song. We call it a Type II song, because it’s slightly different to those used in courtship and territorial disputes. But there’d better be a good reason for it, otherwise males are basically raising their beaks to the heavens and proclaiming to their worst enemy, “Come and get me!”

We have two possible explanations for this behaviour.

The first is that males are stealing the butcherbird’s air-time. Let me explain: if a predator starts calling nearby, then the whole forest turns its ears in that direction. What better time to get your advertising out there? Male fairy-wrens are simply “hitchhiking” their own song on top of the butcherbird’s, making sure that it’s heard by as many females as possible.

The other major theory is that it’s a signal of male quality. For example, in the human world, there’s only one reason why men climb mountains and wrestle alligators, and that’s to impress women.

This plucky moment at the Grampians is yet to score me a single date. Source: Own work

We think that male fairy-wrens may be doing the same. By singing when there’s a predator nearby, they’re exclaiming to females, “Look how brave I am, come adulterate with me.”

Because, as you’ll remember, fairy-wrens are all about that.

#3 They learn secret passwords before they’re born

We’ve all laughed disdainfully at those couples who read to their children while they’re still in the womb. It seems the height of pointlessness… although, come to think of it, Aktil’s Big Swim may actually be more relatable to a foetus bathing in amniotic fluid.

In fairy-wrens, the idea may not be quite so ridiculous. A study published just last year reported some incredible findings: fairy-wrens learn their mother’s incubation call while they’re still inside the egg. This incubation call is a simple vocalisation made by the mother while she sits on her eggs. She stops making the call before her eggs hatch, but, once they do hatch, her chicks will beg for food using signature elements from their mother’s incubation call. There’s definitely learning going on, because, even when you switch eggs between nests, chicks will learn the calls of their new foster mother.

Incubation call
A typical female incubation call, in audio and spectrogram form. Source: Colombelli-Négrel et al. (2012) via GrrrlScientist (2012)

The authors of this study argue that this pre-hatching homework serves an important function: it helps weed out nest impostors. These impostors are usually cuckoos, who raise chicks by laying their eggs in another species’ nest and hoping somebody else will do all the hard work (this is known as “brood parasitism“).

Fairy-wrens regularly face the problem of brood parasitism, and sometimes it’s difficult to spot the difference between a baby wren and a baby cuckoo. This newly-discovered incubation call could be a “password” that evolved to combat such deception. Because cuckoo chicks have less time to memorise the incubation call of the fairy-wren mother, they can presumably be identified and discarded.

A nine-day-old fairy-wren, already contemplating home security. Source: Own work

So there you have it! The superb fairy-wren sleeps around freely, is fearless in the face of danger, and speaks in code. It’s basically the James Bond of the skies.

You’re welcome.

This blog post was originally published by Andrew Katsis on the science blog Mindboggled on May 4 2013.


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