-Ben J. Novak
Revive & Restore’s Great Passenger Pigeon Comeback began in 2012 with two questions:
- Can we bring back the passenger pigeon to the eastern forests of the United States?
- And if so, why bring it back?
To answer these questions, Revive & Restore with scientists from the University of California, Santa Cruz, sequenced genomes, crunched population models, reviewed historic records and forestry science, and more. This new research significantly reshapes accepted scientific views of this iconic species.
Can we bring back the Passenger Pigeon?
We can’t bring the passenger pigeon back as a exact clone from a historical genome, but we can bring back unique passenger pigeon genes in order to restore its unique ecological role. Through a process of precise hybridization, made possible with modern genome editing and reproductive technologies, we can produce a new hybrid generation of the passenger pigeon ecotype that carries a small but important genetic legacy of its extinct forebears.
Why go through the trouble of reviving the passenger pigeon ecotype?
The passenger pigeon’s ecological role in the environment has long been subject to speculation and debate, and the disagreement in published research launched our project’s own investigation into the species’ natural history.
So far we’ve discovered that:
- The passenger pigeon’s lineage originated 12 million years ago. 1
- This species was exceptionally evolved to live in dense flocks, which numbered in the billions for tens if not hundreds of thousands of years before its 1914 extinction.2
When we combine these insights with a review of forest ecology, it reveals a clear understanding that the species was the key engineer of forest dynamics in the eastern North. This new understanding of passenger pigeon ecology presents a strong case for de-extinction. Bringing back the passenger pigeon will restore the dynamic forest regeneration cycles that dozens of presently declining plant and animal species need to thrive.
Now that the unique ecological role of the passenger pigeon compels us to pursue de-extinction, we need to figure out how best to reintroduce a new generation of pigeons and restore that ecology. This is an effort all residents of the passenger pigeons’ historic home range can help to piece together.
The best starting point is expanding our knowledge of the passenger pigeon’s ecological interactions with other species. We know the passenger pigeon’s most significant ecological relationship was with the trees from which it ate seeds, nuts, and fruits. But was the passenger pigeon a seed disperser or a seed predator? What seeds could it eat? And how did this diet influence the evolution of forests?
These were the questions addressed by our most recent publication, “Experimental Investigation of the Dietary Ecology of the Extinct Passenger Pigeon, Ectopistes migratorius,” available open source in Frontiers in Ecology and Evolution.3
Based on observations of closely-related living pigeon species, it was determined that the passenger pigeon’s biggest impact on trees was as a seed-predator – a seed-eating animal that destroys the seeds it consumes. In order to ensure enough seeds survive to germination, tree species would evolve, either by changing the timing of fruiting, producing excess nuts (predator satiation), or growing nuts too large to eat.
We can model the size of the passenger pigeon’s mouth (termed “gape”) to figure out what nut types were too large to eat, thereby interpreting how trees evaded the pigeon’s voracious appetite. This simple piece of information offers huge insights, not only about the co-evolution of passenger pigeons and trees but also the ecological pressures of passenger pigeon flocks on other seed-eating animals. An area rich with nuts too large for a pigeon to swallow would provide ample food for other seed-eaters, particularly larger animals such as turkey and deer, or animals that can break nuts down by chewing such as rodents. In areas dominated by smaller seed-bearing trees, competition pressure from a flock of passenger pigeons would have been intense, resulting in exclusion of other seed eaters and a cascade of trophic effects, possibly beneficial to both biodiversity (allowing generalist and secondary food competitors a chance to fill the void left by primary competitors) and human health (areas of reduced acorn crops see a reduction in rodent numbers, correlating to fewer instances of Lyme disease).
How You Can Help
To fully comprehend the impact, both past and future, of passenger pigeons on forest ecology we need to collect data throughout its former range. That’s where you can help. By printing out the citizen science sheets included here and following the instructions you can join The Great Passenger Pigeon Comeback’s team to assess the impacts of a future flock of passenger pigeons in your own backyard or favorite recreational area. Submit your data to [email protected], and we’ll compile the data to begin mapping the results here on our website, updating as more data comes in for everyone to see how future passenger pigeons will shape forest communities. With this data we’ll be able to plan the here on our website, updating as more data comes in for everyone to see how future passenger pigeons will shape forest communities. With this data, we’ll be able to plan the most effective strategies for a successful and beneficial release of a new generation of passenger pigeons to eastern North America. Someday in the future, dense flocks of pigeons will restore forest regeneration cycles, ensuring the survival of woodland biodiversity for tens of thousands of years to come – and it will be thanks to your involvement!
Revive & Restore partnered & co-sponsored Passenger Pigeon Research to Date:
- Soares, André E. R. et al. 2016. “Complete Mitochondrial Genomes of Living and Extinct Pigeons Revise the Timing of the Columbiform Radiation.” BMC Evolutionary Biology 16: 230. doi: 10.1186/s12862-016-0800-3.
- Murray, Gemma G R and Soares, André E R et al. 2017. “Natural Selection Shaped the Rise and Fall of Passenger Pigeon Genomic Diversity.” Science 358(6365): 951–54. doi: 10.1126/science.aao0960.
- Novak, Ben J et al. 2018. “Experimental Investigation of the Dietary Ecology of the Extinct Passenger Pigeon, Ectopistes Migratorius.” Frontiers in Ecology and Evolution 6: 20. doi: 10.3389/fevo.2018.00020.