This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Australia is home to a strange, yet wonderful, animal diversity. Although the Land Down Under is mainly known for it’s unusual marsupials, venomous snakes and scary spiders, Australia also has a substantial diversity of birds. In fact, this country is one of the greatest hotspots for avian species. Among these, the Superb Lyrebird, Menura novaehollandiae, surely represents one of Australia’s most fascinating. The Superb Lyrebird is one of the largest of the Passerines, the group that comprises over 50 percent of all bird species. The Passerines are commonly known as perching birds and also, less accurately, as songbirds.
M. novaehollandiae are sometimes described as a cross between a pheasant and a peacock since they are roughly poultry-size and because the males have fanned tails like peacocks. However, their tail feathers aren’t as elaborate as a peacock’s; instead, male Superb Lyrebirds have two types of tail plumage; a bunch of lacy feathers and two outermost curled-tip feathers that resemble a lyre (an ancient Greek harp) when upright. That’s the origin of “lyrebird”; the “superb” part of their common name stems from their impressive ability to mimic sounds of their environment.
All perching birds have a well-developed vocal organ called the syrinx, which is equivalent of humans’ vocal cords. The syrinx is located at the bottom of the trachea and is surrounded by an air-sac, allowing the organ to act as a resonating chamber for sound. Basically, the syrinx is how passerines produce tweets, chirps and melodies. The more developed the syrinx, the wider the variation of sounds that can be produced. For example, crows, which have relatively primitive syrinxes, caw in a monotone; the syrinxes of chickadees are more highly developed, allowing these birds to sing; and parrots, more developed still, can produce all sorts of sounds, including what sounds uncannily like human speech. To produce a sound, the bird varies the air pressure, which influences the tensions of the syringeal muscles on the vibrating membranes of the syrinx itself. It takes effort and energy to vary the intensity and frequency of the vibrations, which results in changes loudness and pitch.
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The birds that do this best are those with mimicking talents like the parrot—or the Superb Lyrebird. As young chicks, lyrebirds imitate their parents’ vocalizations but as they mature, their repertoire of sounds increases as they take in noises from the broader environment. The male’s ability to impeccably imitate sounds plays a big role during mating season. Between the months of June to August, males dramatically display their collection of sounds to put on a show for the females. The loudness, fullness, and complexity of a male’s song indicates his level of fitness, a major factor for females in choosing a suitable mate.
Now here is where is gets interesting. As, tourism, technology and infrastructure have spread, the sounds gizmos and gadgets have become mixed in with the sounds of nature. Cellphones ring, vehicles honk, cameras click, and construction equipment buzzes and rumbles. Where most animals aren’t exactly pleased by the extra noises, male Superb Lyrebirds have begun to incorporate them in their courtship display. It’s pretty darn impressive to listen to male Superb Lyrebirds reproduce the sounds of an entire toolbox. Hammer? Check. Chainsaw? Check. How about a car alarm? No problem. Don't believe it? Watch this.
At a first glance, the spectacle is comical and even entertaining, but the Superb Lyrebird’s 21st century sound palette is a direct result of human interference with its natural environment. We know that humans are influencing the behavioral adaptations of animals, but usually this involves climate change and habitat reduction. With the Superb Lyrebird, it represents a case where humans aren’t harming the species, but are indirectly influencing the species’ courtship behavior. If more technological sounds get incorporated into the Superb Lyrebird’s memory, how will that affect the vocal organ over time? This beginning has definitely shed some light on M. novaehollandiae‘s level of intelligence. If the Superb Lyrebird is this superb now, it is very interesting to ponder what will occur over the next decades.