How many is a lot? When you’re talking passenger pigeons, that question is more controversial than you might think.
I was fortunate to be able to participate in a discussion of passenger pigeon population numbers for the Outside/In podcast, which is a production of New Hampshire Public Radio. Author Charles Mann was also interviewed because his book, 1491, repeated an earlier claim that passenger pigeon remains are rarely found on archaeological sites and questioned whether passenger pigeons were truly abundant before the 1800s.
Listen to the episode, Tempest in a Teacup, at the Outside/In website, or wherever you normally get your podcasts.
To celebrate the Smithsonian Institution’s formal announcement of its Open Access program, which makes almost 3 million digital images and 3-D models freely available, here’s one of Martha (a.k.a. USNM 223979), the last passenger pigeon. Viewed from this angle, she has a bit of an attitude.
The New Jersey State Museum‘s Fine Feathered Friends exhibit combines mounted birds from the natural history collection with ceramic birds from the fine arts collection. Two extinct birds, the Carolina Parakeet (Conuropsis carolinensis) and the Passenger Pigeon (Ectopistes migratorius), are immortalized by the Stangl Pottery Company/Fulper Pottery Company of New Jersey.
I recently stumbled upon two more passenger pigeon mounts I was unaware of. The Horninam Museum and Gardens in London, England, has two mounted passenger pigeons, a male and a female. Photos of the birds (NH.Z. 1768 and 1769) can be seen at the museum website.
The two pigeons are part of a natural history collection amassed by Samuel Prout Newcombe in the nineteenth century. Newcombe had owned a number of photography studios in London in the mid 1800s. He also was a writer, and in 1851 wrote a guide to the The Great Exhibition (also known as the Crystal Palace Exhibition) that focused on foods of the world, including an entry on the passenger pigeon. Around 1870, Newcombe sold his photography studios and retired to life a leisure.
Keenly interested in natural history, Samuel Prout Newcombe had amassed a large collection of specimens and books on natural history. … “Nature“, the International Journal of Science, reported in 1899 that: “Mr. S. Prout Newcombe has offered the London County Council his educational collection of natural history specimens and literature. This collection, which consists of about 21,000 objects, included a considerable number of works on natural history subjects“.
This passenger pigeon egg is from the collection of James Bond, the real ornithologist and inspiration for the fictional spy. Bond worked at the Academy of Natural Sciences in Philadelphia and specialized in Caribbean birds. According to the label, the egg was collected in 1849 (not by Bond, who was born in 1900). It was later obtained by Jacques Perrin de Brichambaut and is now in the collection of the Muséum de Toulouse (Muséum d’Histoire Naturelle de la ville de Toulouse) in France.
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.