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Can Six Eggs Show Whether Passenger Pigeons Became Functionally Extinct?

Passenger Pigeon Egg
Egg of Passenger Pigeon. Collection of James Bond /Jacques Perrin de Brichambaut. Source: Didier Descouens Creative Commons-Share Alike 3.0/Wikimedia.

David L. Roberts, Ivan Jarić and Andrew R. Solow, attempt to test the hypothesis that passenger pigeon became functionally extinct, “defined as permanent reproductive failure prior to true extinction” (p. 3) before their actual extinction in the wild around 1902.

Martha, the last captive passenger pigeon, of course, survived until 1914, and you could say that the passenger pigeon truly became functionally extinct by 1910 when George, the last captive male pigeon died. Roberts and colleagues, however, are trying to test a hypothesis some researchers have raised in recent years, that wild passenger pigeons needed to gather in enormous flocks to reproduce successfully. According to this argument, once those great nestings were no longer possible because of overhunting and harassment at the nesting sites by humans, the passenger pigeon was doomed to extinction, even though many thousands of them were still alive.

Therefore, it’s interesting that, based on their statistical test, the authors conclude that the passenger pigeon actually was not functionally extinct. I’ll leave it to mathematicians to evaluate the actual statistical method, but a big question is whether the data they used in their study is robust enough to support that conclusion. That data is records of eggs and skins in museum collections across the world (obtained from the Ornis2 database) collected between 1825 and 1900, with most of the samples from roughly the 1860s to 1890s. Their sample consists of 213 skins and 44 eggs. For reasons that are not clear in the article, they further reduce their sample to specimens collected from 1890 onwards (the “observation period”). Their sample size? Twenty-seven skins and six eggs. Unaddressed is the issue of data quality. The museum specimens were not systematically collected and really can’t be considered a random sample representative of the wild population at the time. The data in Ornis2 also may not be complete; there is an egg collected in Minnesota in 1895 (see Greenberg), for example, that is not included in the six eggs from the 1890s used in their study.

It is important to develop new methods of studying extinction, and if this work does that, it will be valuable, but I caution against putting too much weight on the conclusion regarding the extinction of the passenger pigeons.

Press Release from University of Kent: It may not have been too late to save ‘extinct’ Passenger Pigeon

On the functional extinction of the Passenger Pigeon (accepted manuscript in Conservation Biology)

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The Video Rental Store/Passenger Pigeon Connection

It’s just a passing simile, but reviewer Joe Hill compares video rental stores, ubiquitous just a decade or two ago, with passenger pigeon flocks in his review of the book Universal Harvester, a mystery of sorts by lead Mountain Goat John Darnielle.

Was the disappearance of video rental stores from the American landscape a sudden, overnight event, or were there clues that their demise was coming? That question played out on a smaller scale in the first episode of Starlee Kine’s first episode of the Mystery Show podcast, which itself now appears to be as extinct as the passenger pigeon. What is not extinct, however, it the video rental store. In fact, the largest video rental store is thriving, with 759 stores in the Midwestern U.S. and in Canada.

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Prehistory of the “Feathered Tempest”

Beloit College has posted the video of zooarchaeologist Steven Kuehn’s talk on the prehistoric occurrence of the passenger pigeon in the Midwest.

Kuehn briefly surveys passenger pigeon bones at archaeological sites in the Southeast and Northeast (with a mention of both the Lamoka Lake and Cole Gravel Pit sites), but focuses on the area he knows best, Illinois and Wisconsin.

While I disagree with his assertion that Ectopistes bones are, in general, rare in prehistoric archaeological sites, Kuehn makes some interesting points about possible changes through time in the abundance of passenger pigeon and also shows how, at least in later prehistory, passenger pigeons may have had greater symbolic importance.

Kuehn also talks about his own work at the Late Woodland Fish Lake site in Illinois (not far from Cahokia Mounds), where a single feature contained 28 passenger pigeon bones, almost all from the distal wing. Watch the video to see his interpretation of this find.

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Virtual Passenger Pigeon Bones and Digital Zooarchaeology

Digital model of passenger pigeon humerus
Digital model of a passenger pigeon humerus createdfrom an archaeological site. Created by the Virtual Curation Laboratory, Virginia Commonwealth University.

On the 100th anniversary of the extinction of the passenger pigeon, the Virtual Curation Laboratory at Virginia Commonwealth University has just posted the results of a project to create 3D models of passenger pigeon bones. Most of the source bones were excavated from an archaeological site in Virginia. Its a fantastic idea that will make easier for everyone, including scientists trying to identify passenger pigeon at archaeological and paleontological sites.

There are already hundreds of prehistoric sites where this bird has been identified, but it is surprisingly less common to have passenger pigeon identified from historic period archaeological sites.  One factor complicating their identification in historical sites is the challenge of distinguishing passenger pigeon from the similarly sized rock dove, or common pigeon (Columba livia), that  was introduced to North America in the 1600s.  Often when pigeon bones of a certain size are found in historic period sites, they are classified only as Columbidae, or pigeon. It would be nice to see the VCL also produce 3D models of the rock dove, so zooarchaeologists without access to a comprehensive faunal collection might be better able to distinguish these two species.

For more information, see the VCL website.

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Martha’s Anniversary: Passenger Pigeon Events

With the 100th anniversary of the death of Martha, the last passenger pigeon, only days away, Ectopistes-related events are happening everywhere. Here are some to look forward to over the Labor Day weekend and beyond:

Passenger Pigeon Weekend at the Cincinnati Zoo. 

Held at the original home of Martha and co-sponsored by the Ohio Ornithological Society, this event includes a Friday night cocktail party, a Saturday symposium with Joel Greenberg and others, and birdwatching opportunities.

Smithsonian Institution National Museum of Natural History

Once There Were Billions: Vanished Birds of North America has been open since late June. Martha herself can be found here. The Smithsonian is also having a twitterchat about Martha on September 2, 2-3 P.M. EST. Check out #Martha100.

MassMoca

Artists Sayler/Morris have created a new art exhibit at this fascinating museum in North Adams, Massachusetts,  that contemplates the life and death of the passenger pigeon. Here’s more from the museum’s press release:

Eclipse consists of a massive 100-foot video projection, screens on the walls and ceiling of MASS MoCA’s four-story atrium. The video loop shows a flock of passenger pigeons in reverse-negative silhouette lifting out of a life-sized tree, accompanied by sound design consisting of layers of digitally processed human voices. The exhibition offers a space for reflection with a limited-edition artist publication that will include writings by Kolbert, original photography by Sayler/Morris, and archival images.

Eclipse officially opens on September 1.

Williams Center for the Arts, Lafayette College, Easton PA

Michael Pestel’s multimedia art exhibition Requiem, Ectopistes migratorious, “ metaphorically places Martha at the center of the installation in the form of a human-scale birdcage, encouraging visitors to contemplate extinction—of the passenger pigeon, of other species, and perhaps even author Elizabeth Kolbert’s The Sixth Extinction.” It opens September 1 with a presentation by the artist, music, and readings.

Beloit College Center for the Sciences, Wisconsin

On September 8, Steve Kuehn will give a talk entitled The Prehistory of “The Feathered Tempest”: Passenger Pigeon Zooarchaeology in the Upper Midwest focusing on pigeon bones from archaeological sites in Illinois and Wisconsin.

A Shadow Over the Earth: The Life and Death of the Passenger Pigeon

The University of Michigan Museum of Natural History created this exhibit, which is being presented at many venues throughout the country, including the Florida Museum of Natural History, the New Jersey State Museum, and the Harbor Springs Area Historical Society. Many locales are supplementing the display with material from their own collections.

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Passenger Pigeon Lecture at New York State Museum

Next month, the New  York State Museum will be presenting a lecture  on the passenger pigeon.  Jeremy Kirchman is no stranger to extinct birds, having done research on the Carolina parakeet, the (possibly extinct) Ivory-billed Woodpecker, and others.

The passenger pigeon, icon of extinction
September 28, 2014 : 1:00 P.M. – 2:00 P.M.
Description: One hundred years ago, on September 1st 1914, the world’s last Passenger Pigeon died in captivity at the Cincinnati Zoo marking the demise of a species that once numbered in the billion of birds. What were Passenger Pigeons, and what happened to cause their extinction? Please join Dr. Jeremy Kirchman, New York State Museum Curator of Birds, as he presents this lecture on the life and times of America’s “wild pigeon”.

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“quite a famously extinct species”

A female passenger pigeon in the collection of the Whanganui Regional Museum in New Zealand
A female passenger pigeon in the collection of the Whanganui Regional Museum in New Zealand

The Whanganui Regional Museum in New Zealand has three passenger pigeons in their collections, including this somewhat pale female donated to the museum in the nineteenth century by German ornithologist Otto Finsch.

Dr. Erich Dorfman, author of the quote above, described their specimens in this blog post.

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Passenger Pigeon DNA Article Results in Misleading Headlines

OK, that in itself is not news. But the new article by Chih-Ming Hung and colleagues has resulted in headlines like “Humans Aren’t Solely to Blame for Passenger Pigeon Extinction” (Discover Magazine!) and “Humans not solely to blame for passenger pigeon extinction” (ScienceMag!!). Oh, those are actually the same headline.

GrrlScientist over at the Guardian does much better with “Passenger pigeon extinction: it’s complicated” and provides a pretty good review of the paper, including this important quote: “Dr Hung, Professor Shaner and their colleagues were not looking to discount or disregard the pivotal role that people played in the extinction of this bird. Instead, they were seeking to understand how humans could have reduced this seemingly endless population from billions to none in such a short time period.”

What’s less reassuring is the next line: “Dr Hung, Professor Shaner and their colleagues propose that the passenger pigeon’s population was already in a natural nosedive phase simultaneously with human over-exploitation in the late 1800s, and it was the combination of these two pressures led to its sudden extinction.”

And she also unfortunately repeats the contradiction that European immigrants, while engaging in their own “uncontrolled hunting” of passenger pigeons somehow also managed to  relieve hunting pressure by Native Americans.

The obligatory public domain image of a passenger pigeon