An Ex-Pigeon

The RSM takes a hard look at extinction and its impacts

by Gregory Beatty

Passenger pigeon -  photo Darrol Hofmeister

scienceA Roar of Wings: A Story of Extinction
Royal Saskatchewan Museum
Until March

 

Martha lived her entire 29-year life as a passenger pigeon in captivity at Cincinnati Zoological Garden. When she died on Sept. 1, 1914, it marked the extinction of her species — which, at its peak in North America, numbered between three and five billion birds.

Hunting and habitat destruction, both precipitated by settlers flooding into the mid-west, were the cause its demise. More than just a handy survival food, passenger pigeon was regarded as a delicacy. And a thriving market for its meat developed, with some hunts reaching the 10,000 bird bag limit.

(hah, hah, just kidding about the bag limit. Of course there was no limit.)

Sounds incredible, but the pigeons were that prolific. The famed naturalist Audubon (1785-1851) once reported seeing a flock so large it took three days to fly past.

But within a matter of decades the species had been reduced to one bird — Martha.

“Martha was a superstar in her day,” says Glen Sutter, curator of human ecology at the Royal Saskatchewan Museum, where a centennial exhibit commemorating the passenger pigeon’s extinction opened recently. “The public knew she was the last passenger pigeon. People would travel a long way and line up to see her.”

While the principal nesting colonies were in central and eastern North America, passenger pigeons visited Saskatchewan. “They certainly nested here — in the Qu’Appelle Valley, and the south-east,” says Sutter. “And they probably wandered over half the province in search of food.”

A Roar of Wings includes a stuffed passenger pigeon from the museum’s collection, along with biological information on the species and the impact of settlement. But as the subtitle A Story of Extinction implies, the exhibit’s not just about passenger pigeons.

In the one billion years that multi-cellular life has existed on Earth, there’s been five mass extinctions. The Cretaceous-Tertiary, which happened 65 million years ago when an asteroid slammed into the Yucatan Peninsula, is the most famous because of its link to dinosaurs. But there have been four others — the largest being the Permian, which occurred 248 million years ago and saw 96 per cent of all plant and animal species die out.

There’s a recap of that history in the exhibit, along with other museum artifacts — the highlight being a 32-foot long cast of a tylosaur skeleton. Part of the Mosasauridae family, the species inhabited a vast inland sea in western North America 70 to 90 million years ago.

Several other extinct species are profiled, including the mammoth (which died out 10,000 years ago), saber-toothed cat (around 9000 years ago), dodo bird (1662), great auk (1844), plains grizzly (vanished in 1880), Rocky Mountain locust (1892) and Xerces blue butterfly (1943).

In addition to extinct species, the exhibit highlights other species that are at risk of becoming extinct. These include the California condor (down to 22 in 1975, now up to 237 but still endangered), greater sage-grouse (around 54-80 birds left in Saskatchewan), the black-footed ferret, burrowing owl, western bumblebee, Sprague’s pipit and more — much more.

In fact, the rate at which species are disappearing has scientists proposing we’re in the midst of a sixth mass extinction, says Sutter.

“There’s no question that extinction is a natural event, it’s happened before, the fossil record is clear. What’s hard to appreciate from our perspective is the time-frame. An extinction that happens with a meteorite strike has a definite starting point. But it can take thousands of years after that to come to fruition through climate change, ocean acidification, and other things.

“With climate change today, and a number of other large global changes, that’s what we’re seeing. It’s inspired some people to say we’re no longer in the Holocene epoch, we’re in what they call the Anthropocene, or Age of Humans.

“What I’ve read is if we could project 400 years into the future there would actually be a line in the geological record that would identify humanity’s impact on the planet. That’s a staggering idea.”

Dams, canals, clear-cutting of forests, strip mining, industrial-scale agriculture, urban sprawl… there’s no shortage of examples of our impact on Earth. And those activities, which we purportedly undertake for the economic benefit of a global population that’s risen from maybe 200 million 2000 years ago to 7.3 billion today, are devastating thousands of wildlife species.

“We’re changing the playing field pretty quickly and becoming a major selective force,” says Sutter. “Some species will be able to respond and evolve, others won’t.”

Survival of the fittest, pro-development forces might argue. Besides, there will still be plenty of plants and animals left.

We survived the passenger pigeon’s extinction with no problem. So what’s the big deal, right?

Uh — not so fast. Turns out, we didn’t escape unscathed. Acorns, berries, worms and snails were a big part of the pigeons’ diet, and scientists think rodents were able to capitalize on suddenly abundant food sources and that’s led to the spread of Lyme disease (which is transmitted by deer ticks that feed on the rodents).

It’s one example of what’s at stake (scientists call it a cascade effect) if we don’t embrace a more sustainable lifestyle that respects our fellow plant and animal species and the different habitats they need to survive.

“Diversity is the grist on which the mill of natural selection turns,” says Sutter. “If you don’t have diversity in a population, when that selective pressure arrives there’s much less chance of getting through the bottleneck. Only a fraction will make it through.

“And if a wide range isn’t available, species will die out.”

2014-12-11