“If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck,” the old saying goes – but something sounding like an Australian wildlife keeper might be a duck too.
A duck named Ripper has done something never before recorded among any waterfowl; imitate sounds. Although Ripper is sadly no longer with us, his quintessentially Australian voice lives on in audio files investigated in the journal Philosophical Transactions of the Royal Society B. They provide the first scientifically authenticated case of a duck capable of vocal learning, and could open up opportunities to investigate why only certain birds can learn in this way.
Ripper was an Australian musk duck (Biziura lobate), a species where males perform displays to attract females and warn off rivals. Along with non-vocal “paddle-kick” and “plonk-kicks” these displays include so-called “whistle-kicks” where the duck’s feet hit the water accompanied by soft low-frequency sounds and louder whistles.
Instead of singing the song of his people, however, Ripper took to sounds including one seemingly inspired by the hinge on his cage closing, while another sounds like “You bloody foo..”. It is thought his keeper may have called him a “bloody fool” often enough it sank in.
Many birds can learn to imitate sounds, sometimes including human speech. However, every species in which this has been reliably reported belongs to one of three clades: songbirds (including the extraordinary lyrebird), hummingbirds, and parrots. Other birds have innate calls unaffected by sounds they are exposed to. Occasional reports of vocal imitation in other species have never previously been independently verified.
First author of the study, Professor Carel ten Cate of Leiden University, told IFLScience that Ripper’s discovery could be highly valuable to understanding the origins of vocal learning.
“Some songbirds imitate more and better than others,” Professor ten Cate said. “We can look into why, but to understand how vocal learning started we need to know the ancestral trait. That evolved long ago under conditions we can’t determine.”
“Musk ducks must have evolved it much more recently,” ten Cate continued. “We can look at them and related species [that can’t learn vocally] and work out what the differences are.”
One notable clue lies in the fact Australian musk ducks get much longer and more intense maternal care than other waterfowl.
Ripper hatched in 1983 at the Tidbinbilla Nature Reserve, having been incubated by a bantam hen and then raised by hand.
While at CSIRO Wildlife Research, ornithologist Peter Fullagar visited Tidbinbilla regularly and heard from the staff there about Ripper’s capacities. He recorded the sounds Ripper made and placed them in the Australian Sound Archive. The existence of a talking duck was mentioned in books on Australian birds and a PhD thesis, but not really studied during Ripper’s life.
Two decades later, ten Cate was working on a review of vocal learning across bird species. After encountering passing references he tracked down the recordings, and eventually Fullagar. The pair collaborated, turning Ripper’s sound files into sonograms and comparing their shape to humans saying “You bloody fool” or “You bloody food” to confirm the match.
Unfortunately, however, Tidbinbilla was devastated in a bushfire, and many records of Ripper’s life were lost. His keeper has also died, leaving important questions unanswered. For example, ten Cate told IFLScience that we don’t know what female musk ducks thought of Ripper’s mild profanity.
Besides Ripper, Fullagar also recorded another Australian musk duck that showed less memorable vocal learning, imitating the sounds of Pacific ducks, many of which lived nearby.
Ten Cate has previously revealed females of another Australian bird, the budgerigar, find intelligence sexy. He agreed that unrelated Australian birds appear to have a particular facility for vocal learning and related skills, and said it was unclear if this was a coincidence or a product of some distinctive feature of the continent.
The work may inspire vocal researchers to raise other male B. lobate in captivity and see if they are told to duck off.