At the peak, well over a century ago, the comings and goings of passenger pigeons were a true force of nature -- their vast numbers when in flight stretching for miles and literally obscuring the sun.
Experts estimate that in the early history of the country, there were 3 billion to 5 billion of the native birds -- accounting for up to 40 percent of all bird life in North America -- filling the skies from the Great Plains east to the Atlantic Ocean and from southern Canada to northern Mississippi.
"There was nothing else like it," says Joel Greenberg, a Westmont author and consultant on environmental issues. "The bird was unique in the sheer numbers of the population and the aggregations they formed. It just hit you."
A nature lover, history buff and avid birder who co-authored "A Birder's Guide to the Chicago Region," Greenberg said his passion led him to the passenger pigeon for what will be the first book on the subject in more than 50 years.
Along the way, he has become an organizer and point man in the Chicago area for a growing array of educators, curators and others pursuing Project Passenger Pigeon, a national effort geared to the 100-year anniversary in 2014 of the demise of the once seemingly inexhaustible natural resource.
Through a website, downloadable displays, educational materials, exhibitions, public events and other means -- a documentary film and even a symphony are considerations -- the evolving idea is to use the story of the passenger pigeon to promote habitat preservation and species conservation and to get individuals to consider their roles in the process.
"I'm hoping this is a portal, an entry for people who otherwise wouldn't get involved," Greenberg said.
Though the demise of the passenger pigeon spurred many laws and initiatives, human-caused extinctions continue, organizers say.
"It's not so much we want to bemoan the loss of the passenger pigeon; it's the issues the passenger pigeon brings up," explained Steve Sullivan, senior curator of urban ecology at the Chicago Academy of Sciences and its Peggy Notebaert Nature Museum, who is working closely with Greenberg.
"It was here. It was in our backyards. It was American," he said. "We demolished this renewable resource strictly by our own actions."
During his research, Greenberg said, he began considering a broader educational effort tied to the extinction in 1914. About two years ago, he learned that David Blockstein, senior scientist with the National Council for Science and the Environment, had the same thought and the two connected.
"In this day of where we are so connected through the Internet, there really is an opportunity for people, whoever they are and wherever they are, to become engaged with this conservation effort," said Blockstein, who worked on the Birds of North America Project and did his Ph.D. research on mourning doves, the closest relative to the passenger pigeon.
He said the passenger pigeon was one of the signature animals of pre-colonial America and a "lost part of our North American heritage."
"Anybody who lived east of the Mississippi (River) must have been aware of them because of the prodigious flocks," he said.
"I expect that over time we'll have hundreds if not thousands of organizations involved in the effort. Because they are such an iconic species, it has that potential to bring people together."
Relentlessly hunted for food and sport, the number of passenger pigeons diminished noticeably during the 1870s. According to "Extinct Birds" by Errol Fuller, one organized hunting competition required more than 30,000 dead birds to claim a prize. In 1878 in Petoskey, Mich., 50,000 birds per day were killed for nearly five months running, according to the National Museum of Natural History.
The birds were mostly netted and shot, and being the "cheapest protein available," hundreds of millions were sent to markets in the Midwest and East, according to Greenberg. He said some hunters would asphyxiate the birds by burning sulfur under their nests and roosts, or burning the trees where they gathered.
Destruction of its forest habitat for farming and development also contributed to the demise, experts say.
"Humans drove this species to extinction over a period of decades," Greenberg said.
By 1900, the passenger pigeon was all but gone from the wild. A few remained in captivity, with the last, a female named Martha, dying at the Cincinnati Zoological Garden on Sept. 1, 1914. The body was encased in ice and donated to the Smithsonian Institution where it was on display for a time. It remains in the collections of National Museum of Natural History but is not on view.
"The passenger pigeon is the best cautionary tale to the proposition that no matter how common something is, we can lose it," Greenberg said.
Specifics are to come, but organizational meetings have been held in several Midwest states. Greenberg recently returned from Chatham University in Pittsburgh, alma mater of Rachel Carson, the famous scientist and author credited with helping start the modern environmental movement. Representatives from 10 institutions, including the Carnegie Natural History Museum, discussed the passenger pigeon project.
"It was very heartening," Greenberg said. "We're now over 100 different organizations that are participating."
Local communities, libraries, museums, nature centers, and others also are expected to get involved.
"We're looking at this as an educational opportunity," said Megan Dunning, manager of community education and outreach for the Morton Arboretum. "We really want to incorporate some arts elements into this."
The Lake County Forest Preserve District recently agreed to participate, though the extent is to be determined.
"It could grow," said Lynn Hepler, environmental education services manager. "It's a good way to draw attention to sustainable living so we in Lake County can live in better harmony with our surroundings."
Dunning said having a specific symbol should help educational efforts.
"Sometimes, these environmental concerns and problems like extinction that are big and global, you feel yourself removed from the question because it's such a big question," she said. "Sometimes it helps to put a face on the problem."