The male superb lyrebird of Australia is known for its astounding abilities to mimic the songs of other birds and for almost perfectly replicating human-generated sounds such as camera shutters and, sadly, chainsaws. Now, new research finds that these maestros of impersonation sometimes reproduce the sounds of an entire multi-species flock while courting females and during mating, reports Jake Buehler for Science News.
The study, published last week in the journal Current Biology, explains that the male lyrebirds are specifically recreating the sounds a group of birds makes when a predator shows up. When a predator such as a snake or an owl arrives, a so-called “mobbing flock” creates a cacophony of different alarm calls mixed with flapping wing beats as birds try to repel the dangerous interloper.
Per the paper, males tend to deploy this stress-inducing performance when females begin to leave a male’s courtship arena and during the species’ long-lasting bouts of copulation. Crucially, the researchers say no actual predators appeared to be present. The paper’s authors write that this suggests males imitating a mobbing flock could be attempting to deceive the female and keep her from leaving.
"When the female attempts to leave, we think the male is trying to say 'baby, it's dangerous outside. Stay here with me!'" Anastasia Dalziell, a behavioral ecologist at the University of Wollongong and the study’s lead author, tells Anna Salleh of the Australian Broadcasting Corporation (ABC News).
For the study, researchers recorded 11 male superb lyrebirds (Menura novaehollandiae) in the Blue Mountains and Sherbrooke Forest in New South Wales, Australia. Their initial plan was simply to study the birds’ mating dances and astounding range of vocal mimicry, but Dalziell and her colleagues noticed something else going on in the recordings.
Dalziell tells ABC News that when a female enters a male’s carefully cleared out display arena, “he does a special song and dance routine of three songs, each associated with a unique set of dance movements." But if the female was underwhelmed and begins to exit the display arena, the male busts out his best mobbing flock impression. Interestingly, the males also performed their mobbing flock routines while mating with the females.
Audio analysis revealed that the male lyrebirds’ fake alarm calls closely matched the sounds of actual mobbing flocks. The researchers also played the lyrebird’s mobbing flock call to other species of birds and found that these non-lyrebirds responded just as mightily to the fake version as they did to real recordings of mobbing flocks.
The timing of the male lyrebird’s mobbing flock impersonation is suggestive, but Çağlar Akçay, a behavioral ecologist at Koç University in Istanbul who was not involved with the paper, tells Science News that it doesn’t pin down whether the female has been tricked into thinking a threat is nearby.
“Intuitively, it seems that it wouldn’t be exactly adaptive for a female to return to an area—to copulate no less—if she is under the impression that there is a predator around,” Akçay says.
However, as Graham Readfearn reports for the Guardian, there are examples of other species that use similarly deceptive tactics. Male topi antelopes, for example, falsely sound the alarm if a female starts to leave their display arenas. Per the Guardian, the male corn borer moth copies the sounds of predatory bats, which stops the female moth cold and gives the male a moment to swoop in and mate with her.
Per Science News, Dalziell is now looking to test her team’s findings by playing female lyrebirds recordings of real mobbing flocks to see if it induces the same response elicited by the male’s imitation.