Male lyrebirds imitate a flock of birds to scare females into mating

By Priti Parikh

Birds threatened by a predator often call out to encourage other birds to make noise and fly about, repelling the attacker as part of a “mobbing flock”. Now, researchers have found that male lyrebirds can imitate the sound of an entire mobbing flock, which they do during mating or if their advances are rejected by the female.

Anastasia Dalziell of Cornell University in Ithaca, New York, and her colleagues recorded 11 male superb lyrebirds (Menura novaehollandiae) singing in Sherbrooke Forest, Australia.

They found that each of the lyrebirds could, by themselves, imitate the combined alarm calls made by a mobbing flock containing birds from different species. It wasn’t clear why the birds were making these noises as there was no indication of predators on the recordings.

Using pretend predators in the form of a dummy snake and owl, the team recorded real alarm calls from other birds who saw the predators. Those sounds were similar to the imitation sounds made by the lyrebirds.

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The team then played recordings of the actual and imitation sounds using speakers. Both sounds fooled birds from a range of species into flying over the area, as they thought that a bird was being attacked. “It was a superb piece of mimicry,” says Dalziell.

The researchers suspected that the birds could be making the fake alarm calls during mating after they observed two mating events in Sherbrooke Forest while recording audio. They found that the males mimicked the sound of a mobbing flock, even including the noise of wing beats of much smaller birds, during mating.

To investigate, the team set up cameras in areas that male lyrebirds prepare for mating and recorded about a thousand short videos. The footage revealed that the males also imitated mobbing flocks when the female left without mating.

Dalziell thinks the males aimed to scare the females into staying and mating. While male birds are known for using songs to attract a mate, this suggests male lyrebirds can also use them to deceive.

The use of complex songs during mating is unusual, says Christopher Templeton at Pacific University in Forest Grove, Oregon, as is the birds’ mimicry. “It is exciting to see that lyrebirds imitate the sound of mobbing flocks with wing beats,” he says.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2021.02.003

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