As theater seats fill with fans of the popular "Jurassic Park" franchise, real-life de-extinction efforts for the passenger pigeon are taking place, with the Rochester Museum and Science Center playing a crucial role. A "Passenger Pigeon" exhibit currently on view at the museum showcases specimens owned by the institution, sheds light on the story of extinction, and provides insight into the museum's part in the possible revival of the bird after 100 years of extinction.
RMSC is home to one of the nation's largest collections of passenger pigeon specimens, including more than 25 study skins and mounts as well as numerous skeletal remains. The museum has supplied bones and DNA fragments from its specimens to researchers for the San Francisco-based Long Now Foundation's "Revive and Restore" project. These fragments, along with others supplied by other institutions, are being studied using cloning and genetic engineering techniques in efforts to resurrect the species.
Passenger pigeons once made up a significant part of the avian fauna of our region, but were not limited to this area. When ornithologist, naturalist, and artist John James Audubon traveled from Lexington to Louisville in 1813, he documented a continuous flock overhead during the entire journey. The birds were so numerous that they just about eclipsed the sun.
Their numbers were in the billions in the mid-1800's, "but we're not sure if that's a normal process or not, or if it was a massive population expansion," says George McIntosh, RMSC collection director, and a paleontologist and geologist.
In looking at about 30 specimens, there is little genetic variation, "which suggests there might have been a rapid expansion in their numbers, which might have played a role in why they went extinct," he says.
"The natives who lived in this region hunted passenger pigeons for food," says RMSC president Kate Bennett. "We've found their bones in archeological digs that we've conducted of Native American garbage pits."
But the species didn't die out until 1914, after years of being overhunted to fuel the European taste for pigeon pie. Though other factors likely contributed to the extinction, the prevailing talk is that the birds were hunted to extinction with the assistance of new technology — the use of the telegraph aided people in the quick communication of the flock's whereabouts, and the railroads made short work of shipping barrels of birds to meat markets.
RMSC's "Passenger Pigeon" exhibit is contained within the Expedition Earth hall, next to the permanent diorama of passenger pigeons. It includes an overhead fly-zone of models of the birds, and two cases with passenger pigeon specimens, bones, eggs, and nets used to catch them, as well as descriptions about the techniques used in hunting and trapping the birds.
"As an institution that cares about research and collecting the objects of great significance to the natural science of this region," RMSC has always been fascinated with passenger pigeons, Bennet says.
This is not the first time RMSC's collection has been tapped by science. Bennet says that in the 1960's, the museum's egg collection was used to test — and prove — the hypothesis that DDT was responsible for the change in composition in eggshells that was causing the songbirds and raptors to die. Because the pesticide weakened eggshells, the weight of nesting birds crushed their unborn young.
"This exhibit is an example of a big idea in a small exhibit space," Bennet says. "This is a great way that we make our authentic collections relevant and available to our community."
The bird bones in the front of one of the exhibition cases are about 4,500 years old. The project has sourced other samples from specimens that are 8,000 to 10,000 years old. The oldest passenger pigeon specimen on record is about 200,000 years old, owned by another institution. McIntosh says that researchers seek a range of DNA from over time, to learn about population dynamics.
They also seek to achieve a good genetic variability, or the de-extinction will result in a population without much variation. For the same reason, the de-extinction process is more complex than simply cloning an individual. "A flock of clones is not a viable population over time," McIntosh says.
Challenges to the project include deterioration of the DNA over time, and that, as in many cases of extinct animals, the genome is contaminated with bacterial DNA.
McIntosh is also interested in the environmental impact of bringing these particular birds back, and says that passenger pigeons wouldn't have been his choice. "Good lord, if we ever brought these back in the billions, how would we get rid of them?" he says. The birds could devastate forests, breaking tree branches with the weight of their flocks, and destroying property with excrement that would build up to be a foot deep in places.
But beyond simply bringing back an extinct and potentially cumbersome species, McIntosh describes exciting, unfathomable potential involved in genetic studies, including possible medical applications.
"If you can take little fragments of DNA and put them together in a sequence, it means you can also take things out," McIntosh says. "The second you can pull things out, what does that mean for some of the genetic diseases that are out there?" And in the experimental field of gene therapy, scientists insert genetic material into patients' cells in the effort to treat or prevent disease. "Maybe this is the sort of research that would play a role in that."