The discovery of a 14–19-million-year-old foot bone suggests that New Zealand (Aotearoa) was once home to a small species of bird with an extravagant courtship display, a new study reveals.
Unearthed from fossil deposits at St Bathans in Central Otago, the bone shares clear similarities with those of today's bowerbirds – a type of songbird only found in Australia and New Guinea – though the newly-discovered species would have been much smaller.
Researchers, who published their findings in the journal Historical Biology, say the discovery provides evidence that bowerbirds may have lived in New Zealand millions of years ago.
St Bathans bowerbird: a tiny songster
“To many people in the world, bowerbirds were made famous by Sir David Attenborough’s nature documentaries,” says co-author Nic Rawlence from the Otago Palaeogenetics Laboratory at the University of Otago, “and their elaborate courtship behaviours, where males construct an arched structure called a bower, decorated with sticks and sometimes brightly coloured objects like fruit, leaves or even pieces of plastic, all in an effort to attract a mate.”
Named the St Bathans bowerbird (Aevipertidus gracilis), the researchers think the species may have weighed about 33 grams – significantly lighter than the 96–265 grams of modern-day bowerbirds.
The fossil bone most closely resembles that of 'avenue bower builders', a group of bowerbirds that includes the satin bowerbird and flame bowerbird. Found far from its closest relatives, the new species represents an unexpected branch of the songbird family tree.
“If this bird is indeed a relative of the bowerbirds, it could represent an entirely new songbird family for Aotearoa,” says the study's lead author Dr Elizabeth Steell from the Field Palaeobiology Lab at the University of Cambridge.
“That’s especially significant given the limited understanding we have of the ancient songbird fossil record in this region,” she says.
“The St Bathans bowerbird is the latest songbird lineage to have a long evolutionary history in Aotearoa, where the oldest members of many different groups occur here including huia, kōkako, tīeke, piopio and mohua.
“It’s likely that all these species represent the descendants of a rapid burst of evolution and dispersal from Australia to New Zealand.”
The team say that cooling climates before the ice ages, and the impact of these temperature shifts on forest distribution, likely contributed to the extinction of the St Bathans bowerbird.
Discovering the fossil has presented us with a “wonderful and unique” glimpse into the past, says Rawlence, and provides evidence that New Zealand's ancient forests may have supported a wider range of songbirds than previously thought.
The team plans to continue their research at the St Bathans fossil beds. “This was just one fossil: there will be other songbird fossils from the site, and there might be more surprises waiting,” concludes Rawlence.
The study – A possible early bowerbird from the Miocene of New Zealand – was conducted by researchers from the University of Otago, the Museum of New Zealand Te Papa Tongarewa and the University of Cambridge.
Top image: Central Otago, New Zealand. Credit: Getty
More wildlife stories from around the world
- “You’ve got to kill them faster than they can reproduce”: New Zealand's ambitious plan to eradicate invasive animals
- Why researchers studied over 4,000 preserved songbirds from London’s Natural History Museum
- 272 mysterious plains-wanderers found in Australian desert. Here's why the discovery is so incredible
- “The last thing I expected to find”: scientists stumble upon mysterious marsupials hiding in trees on Australian island
