Cloning the Passenger Pigeon? 🪶

by Dr. Oakleigh Thorne, II

I t was 100 years ago that the last Passenger Pigeon (Ectopistes migratorius) died in the Cincinnati Zoo! So this is the centennial year anniversary of the sad event. I have written here before about this amazing kind of bird. When the first settlers came to North America, there were probably somewhere between three and five billion of these “wild pigeons.” Now there are none. Humans exterminated them in less than a century!

Passenger Pigeons roosted and nested in huge colonies that were usually many miles long and often less than a mile wide. As late as 1871, just 43 years before the last of them died, there was a nesting colony reported in Wisconsin that covered 850 square miles and contained millions of these birds!

The big question now is: can scientists clone the Passenger Pigeon and actually bring the species back to life again? The genetic material in the cells of specimens, called “study skins,” that are now in various museum collections, would be the source of the DNA necessary to do the cloning. This process has been called “de-extinction.” It may sound like a “cool” thing to do, but it would be an extremely difficult task, almost impossible.

The two species of extinct animals that scientists have talked about cloning are the Passenger Pigeon and the Wooly Mammoth. Right now this seems like a “mad scientist’s dream.” If it was even possible someday to do this “de-extinction” of the Passenger Pigeon, what would be some of the problems? If it was possible to recreate a male and a female of these birds, would they mate, lay eggs, and raise young? What happened in the early 1900s when there were only a few of them still alive?

In about 1900, we know that Professor Charles Otis Whitman at the University of Chicago had a small colony of Passenger Pigeons alive and in captivity. In 1902 he gave one female to the Cincinnati Zoo. They named her “Martha.” In 1903 he had twelve birds. He had been trying to breed them, but apparently they would not breed in captivity. By 1906 there were only six of his birds left alive. Finally the only Passenger Pigeon still alive was “Martha,” who died on September 1, 2014. She was the last one known.

It seems clear to scientists that Passenger Pigeons, being a very “social” species, must have needed lots of others of their kind around in order to successfully get “in sync” and breed. If there were not enough of them, they apparently would not breed. This is one of the theories on why they became almost extinct so fast. Their numbers suddenly dropped down to just a few. The commercial market gunners and netters had killed off so many that the few that were left just could not build up their numbers again.

So if scientists someday could “de-extinct” the Passenger Pigeon, how many would they have to re-create in order for them to breed successfully? If Professor Whitman couldn’t get his few birds to breed, it seems like we would now have to create a flock of hundreds. Could this ever be possible? If we could do this successfully, would these birds really be “wild pigeons” again and be able to survive in our modern world? There are lots of unanswered questions.

It is exciting to think of what scientists might be able to do in the future. I hope this story might get you interested in studying science. There is so much to still discover.

Dr. Thorne is founder and honorary president of Thorne Ecological Institute in Boulder. They have helped “connect kids to nature” for more than 55 years. For more information about Thorne Natural Science School classes for children, check www.thornenature.org or e-mail info@thornenature.org or call (303) 499-3647.