Meet Tongoenas burleyi, Extinct Giant Pigeon from Tonga
Tongoenas burleyi (right) likely featured the brightly colored plumage of other canopy-dwelling pigeons on the Pacific islands. On the left is the Kanaka pigeon (Caloenas canacorum), another large extinct Tongan species. Image credit: Danielle Byerley.
Tongoenas burleyi inhabited the Tongan islands for at least 60,000 years, but vanished within a century or two of human arrival around 2,850 years ago.
This canopy-dwelling species was about 51 cm (20 inches) long, not including the tail, weighed at least five times as much as the average city pigeon, and could fly.
“When I first found Tongoenas burleyi fossils in a cave on the Tongan island of ‘Eua, I was immediately impressed by their size,” said lead author Dr. David Steadman, curator of ornithology at the Florida Museum of Natural History.
“I said, ‘Oh my God, I’ve never seen a pigeon that big.’ It was clearly something different.”
“Once we began excavating charred and broken remains of Tongoenas burleyi at archaeological sites, we knew it was another human-caused extinction. Pigeons and doves just plain taste good,” he added.
Tongoenas burleyi co-evolved with fruit-bearing trees in the mango, guava and chinaberry families, acting as an essential forest cultivator by spreading seeds to new locations.
“Tongoenas burleyi was likely capable of swallowing fruit as big as a tennis ball,” Dr. Steadman said.
“Some of these trees have big, fleshy fruit, clearly adapted for a big pigeon to gulp whole and pass the seeds.”
“Of the fruit-eating pigeons, this bird is the largest and could have gulped bigger canopy fruit than any others. It takes co-evolution to the extreme.”
Dr. Steadman hypothesized Tongoenas burleyi featured the bright, even gaudy, plumage of other pigeons that live in treetops, where intense colors provide better camouflage than the muted browns and grays of pigeons that live on the ground.
“The absence of Tongoenas burleyi from the Tongan islands could threaten the long-term survival of local trees that depended on the pigeon as a seed transporter,” said co-author Oona Takano, a doctoral student at the University of New Mexico.
“Tongoenas burleyi provided an important service by moving seeds to other islands. The pigeon species on Tonga today are too small to eat large fruits, which imperils certain fruit trees.”
In their study, the researchers analyzed the features of the hindlimbs (femur, tibiotarsus, tarsometatarsus) of the Papuan-Oceanic pigeons and doves, dividing them into three groups: tree-dwelling species, ground-dwellers and those that live both on the ground and in trees.
“We dedicated the study to the memory of W. Arthur ‘Art’ Whistler, whose expertise in West Polynesian botany was unsurpassed. Whistler died from COVID-19 in April,” Dr. Steadman said.
“There wasn’t a plant on Fiji or Tonga that Art didn’t know, including all of the pigeon-dispersed fruits. He was a true plant nerd and complete salt of the Earth. He always made time for people.”
The study was published in the journal Zootaxa.
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David W. Steadman& Oona M. Takano. 2020. A new genus and species of pigeon (Aves, Columbidae) from the Kingdom of Tonga, with an evaluation of hindlimb osteology of columbids from Oceania. Zootaxa 4810 (3); doi: 10.11646/zootaxa.4810.3.1
This article is based on text provided by the Florida Museum of Natural History.
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