It sounded like distant thunder rolling.

Even on a sunny, languid day, blue skies could turn dark amidst a swirl of noise and flapping wings. The passenger pigeon, known to migrate in flocks of millions to find food, might fill the sky for days.

The oval, reddish-breasted bird was the most prolific in North America. But one rifle shot into a passing flock could drop as many as a dozen. A single baited net could trap hundreds. Birds were packed into barrels for sale by commercial hunters. Baby pigeons, or squabs, a delicacy, were knocked from nests with poles.

By the mid 1800s, they were dying out.

“The multitudes of wild pigeons in our woods are astonishing,” John James Audubon once wrote. But the last wild passenger pigeon was sighted in 1902. The last captive one, named Martha, died Sept. 1, 1914, at the Cincinnati Zoo.

The extinction 100 years ago was a call to action. It inspired the passage of the U.S. Migratory Bird Treaty Act and the first successful efforts to protect endangered wildlife.

To mark the centennial, the Museum of Natural History now through January 2015 presents “A Shadow Over the Earth: The Life and Death of the Passenger Pigeon.” Housed in the fourth floor temporary exhibits gallery, four of 32 complete passenger pigeon specimens held by the U-M Museum of Zoology are in the exhibit.

Information panels prepared by the Museum of Natural History for the exhibit are shared for free online through exhibit partner Project Passenger Pigeon, at passengerpigeon.org.

“This marks a new effort by the museum to have its content reach a wider audience,” says Eugene Dillenburg, Museum of Natural History assistant director for exhibits. More than two dozen institutions across the United States and Canada plan to use the panels. Combining art, photos and information, the series of nine 2-by-3-foot panels was produced by former museum studies intern Kaisa Ryding, a School of Art & Design 2014 graduate. “It also represents a new paradigm in the museum field as a whole for sharing content between institutions,” Dillenburg says.

The passenger pigeon’s story is offered as a commemoration and a cautionary tale, as other species of animals are threatened with extinction. A portion of the museum exhibit, “The Passenger Pigeon in Michigan,” celebrates vivid accounts of the bird in Michigan — the first and only state or province to ban its killing. Michigan was among the bird’s favored nesting areas.

This portion was written and researched by Joe Dresch, who holds a Master of Science of Information degree from the School of Information; designed by Juliana Lew, who earned a Bachelor of Fine Arts from A&D (both worked as freelance alumni); and built and installed by UMMNH staff.

“The University of Michigan’s Museum of Natural History has contributed greatly to Project Passenger Pigeon’s effort to inform people about the bird, its story, and the important lessons it offers by mounting a fine exhibit,” says Joel Greenberg, project coordinator, author and research associate with the Chicago Academy of Sciences and Field Museum of Natural History, Chicago. He says the shared panels created by the university have been one of the most valuable tools to help reach large groups of people.

Impossible to imagine

Once, an estimated six billion passenger pigeons roamed eastern North America in enormous flocks. With so many eyes on the lookout, flocks could easily find food. Passenger pigeons preferred beech and oak forests, where they ate lots of nuts and acorns and roosted in trees.

The large flocks provided safety — for a time.

“They were sometimes compared to a tornado — their energy, their noise, and the havoc they could wreak on a forest,” Dillenburg says. The birds didn’t bother crops much, preferring to feed on the mast or natural food of the forest. Thick tree branches would bend or snap under the weight of hundreds of perching birds.

And there was pigeon feces, “not unlike melting flakes of snow,” Audubon wrote. “You have a couple million birds nesting in a forest. There would be up to 2 feet of pigeon poop on the ground, which sounds kind of gross, but after a couple years you get really, really rich soil,” Dillenburg says.

Audubon famously described a flock he saw in 1813 in Kentucky, covering the entire horizon. It took three days to pass. Fur trader Chief Simon Pokagon, a Native American of the Potawatomi Nation, recalled encountering a massive flock at the headwaters of the Manistee River in 1850:

“I was startled by hearing a gurgling rumbling sound as though an army of horses laden with sleigh bells was advancing through the deep forests toward me … I beheld moving toward me in an unbroken front millions of pigeons; the first I had seen that season. They passed like a cloud through the branches of the high trees through the underbrush and over the ground … They fluttered all about me (alighting) on my head and shoulders gently.”

A rich resource

Dillenburg says the passenger pigeon, which flew great distances at high speed, evolved big wing muscles. This provided for humans a cheap, meaty source of protein; a natural resource easy to exploit. He said technology aided the bird’s demise. “Once America laid railroad tracks and telegraph lines everywhere, it was possible to announce major nestings, say in Petoskey. Hunters would go up there and fire away for weeks at a time,” Dillenburg says.

Passenger pigeon hunting items in the exhibit include a large net and a pigeon stool. “It looks like a tennis racket with a very long handle attached to a vertical pole stuck in the ground. The hunters would tie a live pigeon to the tennis racket part, then go off and hide in the bushes. As the flock flew overhead they would pull a string to shake the stool, making the decoy pigeon flap its wings. That would attract the rest of the flock to land, figuring it was a safe place. Once they did, the hunters would spring the net and capture several hundred pigeons at a time,” Dillenburg says.

Ryding says passenger pigeons relied on their large populations so much that when their population was reduced to the thousands, they could not function as a flock, and very quickly died out.

The exhibit includes the 1907 book by William B. Mershon, “The Passenger Pigeon,” the first devoted to the bird. Mershon, who served as mayor of Saginaw, was an early conservationist. He tried to present information about the passenger pigeon through remembrances, “before all the eyewitnesses were gone.”

The exhibit includes a painting of a passenger pigeon by Louis Agassiz Fuertes, who was considered after Audubon to be America’s finest nature painter. In the following, Audubon described the bird in his essay “The Passenger Pigeon”:

“Their body is of an elongated oval form, steered by a long well-plumed tail, and propelled by well-set wings, the muscles of which are very large and powerful for the size of the bird. When an individual is seen gliding through the woods and close to the observer, it passes like a thought, and on trying to see it again, the eye searches in vain; the bird is gone.”

More exhibits

Sara Adlerstein-Gonzalez, associate research scientist in the School of Natural Resources and Environment and the school’s Arts and Environment Gallery director, says the gallery will present the touring art exhibit “Moving Targets: Passenger Pigeon Portrait Gallery” commemorating the passenger pigeon this fall. It was organized by Ann Rosenthal and Steffi Domike and includes works by 14 artists living in states where the bird did nest.

She says SNRE students from the Art and Environment Group in collaboration with the Ann Arbor Zoological society are working on supporting exhibit projects on extinction and conservation. They include a flock of passenger pigeons decorated by kids in summer camp, a commemoration wall for people to offer thoughts on conservation, and a children’s dance performance.

Ryding says that while humans drove the passenger pigeon to extinction, society now tries to stop other species from going extinct through legislation and actions to preserve and rebuild environments. She says the best solution is to avoid endangering species in the first place.

“It’s so strange to think that entire generations in the U.S. have never seen a passenger pigeon when it used to be the most common bird on the continent,” Ryding says.