Superb he may be, but new research shows just how deceptive the male lyrebird can be in trying to lure a partner into his den. University of Wollongong expert Dr Anastasia Dalziell spoke to Ben Langford.
Gorgeous, elusive, and an expert mimic, the Superb lyrebird is one of the world's most fascinating creatures. The male's vocal skills are well known - mimicking anything from chainsaws to toy laser guns. But new research has found he mimics the sound of a panicked flock of birds in what appears to be a bid to keep a potential mate around his mound.
The sound of the "mixed species mobbing flock" is well known among bird watchers, and comes when a predator is spotted nearby, but not threatening immediately. Many birds rise together to warn off the predator, with the distinctive cacophony easily identifiable.
And by using sonograms to compare the flock's particular acoustic structure, it's been found that male lyrebirds make exactly this sound at two moments in the mating ritual: while actually copulating, and if a female decides she's had enough and goes to leave.
It's coupled with a penchant for covering the female's eyes with his wings while mating, as if to protect the deception.
"It's a bit like saying, 'Baby, it's dangerous out there. Stay here with me', said the study's lead author, UOW research fellow Dr Anastasia Dalziell.
"We can't say for certain that's what they're doing, but it is a very odd behaviour that could be explained this way, that they're trying to prevent the female from detecting the deception. This is only one strategy that the males use - we have focused in great deal on this very complex and bizarre behaviour, but it's only one of the many strings to their bow.
"It all starts at the beginning of the breeding season - the males sing their dawn chorus. They're singing at the tops of the trees. This is what we call their recital song - it's long stream of imitations - kookaburras, crimson rosellas, eastern whipbirds, grey shrike thrushes, they spiel through them. That's almost as though they're broadcasting to as wide an audience as possible - this is where I am, this is how good I am. The first step to getting a mate is to persuade a female to come visit the mate on his territory.
"Then if she does come and visit, he'll take her to one of his display platforms, his dancing arenas, called display mounds, a circular patch on the forest floor, about 1-2m. Then he throws his tail over his head in full display position, and that's when he does the laser guns (and other sounds) - it's his own original song. He has three songs that form part of a co-ordinated dance routine.
"It's a bit like theatre in the round, or the Globe. It's very small and intimate - you're right there with the performer. In fact his tail is often over her at particular moments. If all goes well, then he gets on top of her and mates, and that's when he imitates the mixed-species mobbing flock."
Deceptive, most likely. But before we write off the lyrebird as a sleazebag, bear in mind the female retains her position of being able to choose who she mates with.
"There's multiple stages before you even get to the mobbing flock - and at any stage the female can either not approach him on his territory, or she can not go onto the mound, she can leave the mound, and if she does leave the mound without him mating that's the second context in which he produces a mixed species mobbing flock," Dr Dalziell said.
"And sometimes she comes back. 'Stay a while here with me and in the meantime I'll show you what I can do'. So the males are pulling out all the stops to get her to agree to mate with him, and to stay for long enough for him to have a reasonable chance of fathering young. And most males won't even get that chance, we suspect. Far more times I've seen a female come with a male and then leave without mating, and sometimes you can hear her going to visit the man next door, and he does his song and dance and she goes off somewhere else.
"Other times I see a male displaying for a long time and he never gets a single visitor."
Her ability to see though the deceptive (and sometimes laughable) ways of the male suitor are likely to be what has caused his mating rituals, songs, tail feathers and dances to grow so extravagant and specialised - he's had to do so, to keep him in with a chance.
With the female evolving to spot deceptions and the male's wiles becoming more sophisticated, it could be something of an "evolutionary arms race", Dr Dalziell said.
"That's part of it - a theory says that it's the selection of females to optimise their control over their reproductive behaviour, and to be completely in control of their decision, and maximise the chance that her young are successful. There's lots of males around, so if she can do so at her convenience, and choose the best male around, when she's ready and when her nest is ready.
"This is what we know from other arms races, that she has the [discretion] to be able to discriminate between a real mobbing flock, which she needs to be very sensitive about. There are many things that could be a threat to her and her chicks. So we think a long period of evolutionary time has led to females being extremely discriminating, and that's why these males go to such lengths.
"This is consistent with them being under strong sexual selection - strong competition between males for females ... elaborate songs, dances, and his astonishing plumage. It all makes sense - it's not definitive, but all these lines of evidence [align]."
Plus, the nefarious behaviour of the males isn't the only nasty work we find lyrebirds getting up to. Researchers, led by Victoria Austin at Western Sydney University, have found female lyrebirds can get rather aggressive in their quest to choose their mate, destroying the nests of other females in what is called reproductive suppression.
The female is just seeking to be in control of her reproductive choices.
"And it looks like she is, mostly, in control, because he still has to jump through these hoops to get to her," Dr Dalziell said. "He has to sing, he has to do this extraordinary mimicry to get her into his territory in the first place, then he has this amazing display mound, which is a lot of work to make, and to keep them clean, with daily maintenance over lots of mounds. Then he has to produce his song and dance - making sure he has the right moves to the right song. The young makes can't do that, they make mistakes all the time and look really silly. He only does the deceptive mimicry, we think, at this final stage - or when it look like everything is about to fall apart and she's leaving."
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