Male lyrebirds use clever mimicry to increase their chances of sexual success,according to a new study involving researchers from The Australian NationalUniversity.
Lyrebirds are famous for their ability to mimic complex sounds of otherspecies, including “human” sounds like chainsaws. Now biologists think they’vediscovered what drives this skill.
According to study co-author, ANU Professor Robert Magrath, wild males havetwo main types of mimicry.
“They are famous for mimicking the songs of other birds, delivered loudly inbreathtaking recitals,” Professr Magrath said.
“But we found they use a different type of mimicry at their display mounds,where females visit for sex. They use this mimicry when a female tries toleave without mating, and during the act itself – to create the illusion of anearby threat.”
“They use this mimicry when a female tries to leave without mating, andduring the act itself – to create the illusion of a nearby threat.”
Lead author Dr Anastasia Dalziell, a Visiting Fellow at ANU, says thissuggests it’s a deceptive part of male lyrebirds’ sexual strategy.
“They mimic what’s known as mobbing – a common anti-predator ploy. It involvesa loud alarm call to attract other birds to harass a predator, eventuallyforming a noisy flock,” Dr Dalziell said.
“The male lyrebirds not only imitate the alarm calls of several species ofsongbird, they pattern the calls to create the illusion of many birds callingat the same time, even including the sound of wingbeats. It’s a veryconvincing illusion – so convincing it fools other birds into responding.”
This mimicry has the characteristics of a “sensory trap” – with the maleattempting to trick the female into responding as though there’s a predatorthreat.
“Mimicking when the female attempts to leave may be a bit like saying “it’sdangerous outside, stay”, while mimicking during copulation could extend theduration, like saying “freeze”, making sure the sperm is transferred,” DrDalziell said.
The findings were a surprise to the research team.
“At first it seemed absurd, but we quickly realised that mimicking a mobbingflock during copulation was the norm for male lyrebirds. It happened duringevery single copulation we filmed,” Dr Dalziell said.
“The more we researched it the more remarkable this behaviour became.Copulation calls are not common among song birds, and song birds very rarelycopulate for longer than two seconds. The lyrebirds in our study averaged 45seconds.”
Dr Dalziell is currently a postdoctoral Research Fellow at WollongongUniversity, as well as a Visiting Fellow at the University of Western Sydneyand Cornell University in the US.
The team now hope to delve further into how the female lyrebirds respond toboth real and mimicked mobbing flocks.
Their work has been published in the journal _Current Biology. _
Image credit: Alex Maisy, co-author
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