Male lyrebirds in the throes of sexual union will mimic the sound of a distressed mob of other birds to fool their mate and stop her from escaping, new research from Australia has found.
The remarkable discovery was made after analysing audio and video of superb lyrebirds – a species known for extravagant dance routines and an ability to imitate the calls of more than 20 other species.
Researchers found males could simultaneously reproduce both the vocal “mobbing” sounds, and the sounds of beating wings made by other bird species when they’re trying to scare off a predator.
The male lyrebirds mimicry is so accurate it not only fools the female lyrebird, but playback experiments also found other small birds were tricked into thinking there was a threat nearby.
Lyrebirds in captivity have been known to imitate other sounds, including chainsaws and car alarms.
Dr Anastasia Dalziell, a behavioural ecologist at the University of Wollongong, led the research published in the journal Current Biology.
“Male lyrebirds are capable of doing amazing things and terrible things,” she said.
Dalziell first heard lyrebirds mimic the mobbing calls in 2007 and went on to study the ability in detail in two populations – one in Sherbrooke Forest in Victoria, the other in the Blue Mountains in New South Wales. These locations are 700km apart.
Along with her colleagues, she was sure the mimicking had something to do with mating but wasn’t immediately clear on why.
But other scientists pointed out a similar behaviour in other animals. Male topi antelopes use a false alarm call if females move away from their “display arenas”.
The male corn borer moth will mimic the sound of predatory bats for long enough to cause a female to freeze, giving the male time to mate.
“Lyrebirds are using the same strategy, but doing it in a really over-the-top way, like lyrebirds seem to do,” Dalziell said.
The research found male lyrebirds only reproduced the sound when they had enticed a female onto their “display area” – a small space in the forest, cleared for courtship – or when they were copulating.
These two moments, Dalziell says, are crucial to reproductive success “suggesting that mimicking a mobbing flock is a crucial sexual behaviour for males”.
She said they were further convinced when their camera footage showed female lyrebirds reacting to the mimicking calls and returning to display areas.
When the mimicking calls were analysed in detail, researchers could detect mobbing calls that sounded like eastern yellow robins, brown thornbills, and white-browed scrubwrens. Occasionally, the researchers detected alarm calls that sounded like two species of possum.
To compare the imitated mobbing chorus to a real one, Dalzielle said they had to employ their own deceptive behaviour to get local birds to reproduce the calls.
“We threw in a rubber snake,” she said.
The male lyrebirds always employed their deceptive trick if females tried to escape while mating, Dalziell said.
“Males are pulling out all the stops to get the female to mate. It’s just one of the many things males do.
“They have this beautiful dance routine and they’ll sing from dawn until dusk and so the female is getting all these other beautiful signals. We shouldn’t see the lyrebirds as terrible.
“We do have a tendency to romance about the lyrebird, but they’re animals and are capable of amazing things. But they also do things we don’t like or find troubling and problematic, just like people.”
Lyrebirds will routinely mimic other species and Dalziell said their repertoire extended beyond 20 different species.
“They only imitate local species. They do it mainly in the breeding season and it’s part of their dawn chorus – and it is very, very accurate.”
