Editing Passenger pigeon (section)

==Relationship with humans==
[[File:Mershon's The Passenger Pigeon (Audubon plate, crop).jpg|thumb|left|upright|Billing pair by [[John James Audubon]], from ''[[The Birds of America]]'', 1827–1838. This image has been criticized for its scientific inaccuracy.]]

For fifteen thousand years or more before the arrival of Europeans in the Americas, passenger pigeons and Native Americans coexisted in the forests of what would later become the eastern part of the continental United States.<ref name="archaeology">{{Harvnb |Greenberg|2014 |pp=[https://books.google.com/books?id=6SLBAgAAQBAJ&pg=PA31 31–35]}}</ref><ref name="pre-clovis">{{citation |last=Goodyear |first=Albert C. |title=Evidence of Pre-Clovis Sites in the Eastern United States |journal=Paleoamerican Origins: Beyond Clovis |year=2005 |pages=103–112 |url=https://scholarcommons.sc.edu/cgi/viewcontent.cgi?article=1026&context=sciaa_staffpub}}</ref><ref name="Figure 1B">{{citation |last=Novak |first=Ben J. |title=Deciphering The Ecological Impact of the Passenger Pigeon: A Synthesis of Paleogenetics, Paleoecology, Morphology, and Physiology |work=UC Santa Cruz |year=2016 |pages=10–11 |url=https://escholarship.org/content/qt3260s35t/qt3260s35t.pdf}}</ref> A study published in 2008 found that, throughout most of the [[Holocene]], Native American land-use practices greatly influenced forest composition. The regular use of [[prescribed burn]], the [[girdling]] of unwanted trees, and the planting and tending of favored trees suppressed the populations of a number of tree species that did not produce nuts, acorns, or fruit, while increasing the populations of numerous tree species that did. In addition, the burning away of forest-floor litter made these foods easier to find, once they had fallen from the trees.<ref name="influenced">{{citation |last1=Abrams |first1=Marc D. |last2=Nowacki |first2=Gregory J. |title=Native Americans as active and passive promoters of mast and fruit trees in the eastern USA |journal=The Holocene |volume=18 |issue=7 |year=2008 |pages=1123–1137 |bibcode=2008Holoc..18.1123A |doi=10.1177/0959683608095581 |s2cid=128836416}}</ref> Some have argued that such Native American land-use practices increased the populations of various animal species, including the passenger pigeon, by increasing the food available to them,<ref name="explains">{{citation |last1=Delcourt |first1=Paul A. |last2=Delcourt |first2=Hazel R. |title=Prehistoric Native Americans and Ecological Change: Human Ecosystems in Eastern North America Since the Pleistocene |publisher=Cambridge University Press |place=Cambridge |series=Cambridge Studies in Ecology |edition=1st |year=2004 |isbn=978-0-521-66270-3 |url=https://books.google.com/books?id=BUIki2XK7BgC&pg=PA4}}</ref><ref name="favored">{{cite book |last=Little |first=Silas |chapter=7. Effects on Forests: Northeastern United States – I. Frequency and Type of Presettlement Fires |editor1-last=Kozlowski |editor1-first=T. T. |editor2-last=Ahlgren |editor2-first=C. E. |title=Fire and Ecosystems |date=1974 |chapter-url=https://books.google.com/books?id=Nrg-EP-1oVcC&pg=PA226 |location=New York |publisher=Academic Press |page=226 |isbn=978-0-12-424255-5}}</ref><ref name="abundance">{{citation |last1=Thompson |first1=D. Q. |last2=Smith |first2=R. H. |name-list-style=amp |title=The forest primeval in the northeast -- a great myth? |work=Proceedings Annual [10th] Tall Timbers Fire Ecology Conference: a quest for ecological understanding. Fredericton, New Brunswick, Canada |location=Tallahassee, FL |publisher=Tall Timbers Research |pages=261–265 |year=1971 |url=https://talltimbers.org/wp-content/uploads/2014/03/ThompsonandSmith1970_op.pdf}}</ref> while elsewhere it has been claimed that, by hunting passenger pigeons and competing with them for some kinds of nuts and acorns, Native Americans suppressed their population size.<ref name="claim">{{Harvnb |Greenberg|2014|p=[https://books.google.com/books?id=3-qnBQAAQBAJ&pg=PA34 34]}}</ref> Genetic research may shed some light on this question. A 2017 study of passenger-pigeon DNA found that the passenger-pigeon population size was stable for 20,000 years prior to its 19th-century decline and subsequent extinction, while a 2016 study of ancient Native American DNA found that the Native American population went through a period of rapid expansion, increasing 60-fold, starting about 13–16 thousand years ago. If both of these studies are correct, then a great change in the size of the Native American population had no apparent impact on the size of the passenger-pigeon population. This suggests that the net effect of Native American activities on passenger-pigeon population size was neutral.<ref name="Selection"/><ref name="expansion">{{citation |last1=Llamas |first1=B. |last2=Fehren-Schmitz |first2=L. |last3=Valverde |first3=G. |last4=Soubrier |first4=J. |last5=Mallick |first5=S. |last6=Rohland |first6=N. |last7=Nordenfelt |first7=S. |last8=Valdiosera |first8=C. |last9=Richards |first9=S. M. |last10=Rohrlach |first10=A. |last11=Romero |first11=M. I. B. |last12=Espinoza |first12=I. F. |last13=Cagigao |first13=E. T. |last14=Jiménez |first14=L. W. |last15=Makowski |first15=K. |last16=Reyna |first16=I. S. L. |last17=Lory |first17=J. M. |last18=Torrez |first18=J. A. B. |last19=Rivera |first19=M. A. |last20=Burger |first20=R. L. |last21=Ceruti |first21=M. C. |last22=Reinhard |first22=J. |last23=Wells |first23=R. S. |last24=Politis |first24=G. |last25=Santoro |first25=C. M. |last26=Standen |first26=V. G. |last27=Smith |first27=C |last28=Reich |first28=D |last29=Ho |first29=S. Y. W. |last30=Cooper |first30=A |last31=Haak |first31=W. |display-authors=2 |title=Ancient mitochondrial DNA provides high-resolution time scale of the peopling of the Americas |journal=Science Advances |volume=2 |issue=4 |pages=1–10 |year=2016 |bibcode=2016SciA....2E1385L |pmid=27051878 |doi=10.1126/sciadv.1501385 |pmc=4820370}}</ref>

The passenger pigeon played a religious role for some northern Native American tribes. The [[Wyandot people]] (or Huron) believed that every twelve years during the [[Feast of the Dead]], the souls of the dead changed into passenger pigeons, which were then hunted and eaten.<ref name="Schorger135">{{Harvnb|Schorger|1955|p=135}}</ref> Before hunting the juvenile pigeons, the Seneca people made an offering of [[wampum]] and brooches to the old passenger pigeons; these were placed in a small kettle or other receptacle by a smoky fire.<ref name="Schorger135"/> The [[Ho-Chunk]] people considered the passenger pigeon to be the bird of the chief, as they were served whenever the chieftain gave a feast.<ref name="Schorger136">{{Harvnb|Schorger|1955|p=136}}</ref> The Seneca people believed that a white pigeon was the chief of the passenger pigeon colony, and that a Council of Birds decided that the pigeons had to give their bodies to the Seneca because they were the only birds that nested in colonies. The Seneca developed a pigeon dance as a way of showing their gratitude.<ref name="Schorger136"/>

French explorer [[Jacques Cartier]] was the first European to report on passenger pigeons, during his voyage in 1534.<ref>{{cite magazine |last1=Edey |first1=M. |title=Once there were billions, now there are none |magazine=[[Life (magazine) |Life]] |date=December 22, 1961 |volume=51 |issue=25 |pages=169{{ndash}}176 |issn=0024-3019 |url=https://books.google.com/books?id=blMEAAAAMBAJ&pg=PA170 |access-date=June 16, 2015}}</ref> The bird was subsequently observed and noted by historical figures such as [[Samuel de Champlain]] and [[Cotton Mather]]. Most early accounts dwell on the vast number of pigeons, the resulting darkened skies, and the enormous amount of hunted birds (50,000 birds were reportedly sold at a Boston market in 1771).<ref name="Fuller 2014 50–69">{{Harvnb|Fuller|2014|pp=50–69}}</ref> The early colonists thought that large flights of pigeons would be followed by ill fortune or sickness. When the pigeons wintered outside of their normal range, some believed that they would have "a sickly summer and autumn."<ref name="Schorger12">{{Harvnb|Schorger|1955|p=12}}</ref> In the 18th and 19th centuries, various parts of the pigeon were thought to have medicinal properties. The blood was supposed to be good for eye disorders, the powdered stomach lining was used to treat [[dysentery]], and the dung was used to treat a variety of ailments, including headaches, stomach pains, and lethargy.<ref name="Schorger1323">{{Harvnb|Schorger|1955|pp=132–133}}</ref> Though they did not last as long as the feathers of a goose, the feathers of the passenger pigeon were frequently used for bedding. Pigeon feather beds were so popular that for a time in [[Saint-Jérôme, Quebec]], every dowry included a bed and pillows made of pigeon feathers. In 1822, one family in [[Chautauqua County, New York]], killed 4,000 pigeons in a day solely for this purpose.<ref name="Schorger132">{{Harvnb|Schorger|1955|p=132}}</ref>

[[File:Ectopistes migratoriusMCN2P28CA.jpg|thumb|upright|Painting of a male, K.&nbsp;Hayashi, c.&nbsp;1900]]

The passenger pigeon was featured in the writings of many significant early naturalists, as well as accompanying illustrations. Mark Catesby's 1731 illustration, the first published depiction of this bird, is somewhat crude, according to some later commentators. The original watercolor that the engraving is based on was bought by the British royal family in 1768, along with the rest of Catesby's watercolors. The naturalists [[Alexander Wilson (ornithologist)|Alexander Wilson]] and John James Audubon both witnessed large pigeon migrations first hand, and published detailed accounts wherein both attempted to deduce the total number of birds involved. The most famous and often reproduced depiction of the passenger pigeon is Audubon's illustration (handcolored [[aquatint]]) in his book ''[[The Birds of America]]'', published between 1827 and 1838. Audubon's image has been praised for its artistic qualities, but criticized for its supposed scientific inaccuracies. As Wallace Craig and R.&nbsp;W. Shufeldt (among others) pointed out, the birds are shown perched and billing one above the other, whereas they would instead have done this side by side, the male would be the one passing food to the female, and the male's tail would not be spread. Craig and Shufeldt instead cited illustrations by American artist [[Louis Agassiz Fuertes]] and Japanese artist K.&nbsp;Hayashi as more accurate depictions of the bird. Illustrations of the passenger pigeon were often drawn after stuffed birds, and [[Charles R. Knight]] is the only "serious" artist known to have drawn the species from life. He did so on at least two occasions; in 1903 he drew a bird possibly in one of the three aviaries with surviving birds, and some time before 1914, he drew Martha, the last individual, in the [[Cincinnati Zoo]].<ref name=JAA>{{cite book |author-link=John James Audubon |last=Audubon |first=J. J. |title=Ornithological biography, or, an account of the Habits of the Birds of the United States of America |volume=1 |publisher=A. Black |location=Edinburgh |year=1835 |pages=319–327 |url=https://www.biodiversitylibrary.org/item/103784#page/347/mode/1up}}</ref><ref name="Fuller 2014 50–69"/><ref name="Fuller 2014 124–147">{{Harvnb|Fuller|2014|pp=124–147}}</ref><ref>{{cite journal |last=Shufeldt |first=R. W. |title=Published figures and plates of the extinct passenger pigeon |journal=[[Scientific Monthly]] |volume=12 |issue=5 |edition=5th |pages=458{{ndash}}481 |url=https://archive.org/stream/publishedfigures00shuf#page/458/mode/2up |year=1921 |bibcode=1921SciMo..12..458S}}</ref><ref>{{cite book |last1=Milner |first1=R. |year=2012 |page=138 |title=Charles R. Knight: The Artist Who Saw Through Time |publisher=[[Abrams Books]] |isbn=978-0-8109-8479-0 |location=New York}}</ref><ref name="Craig 1911"/>

The bird has been written about (including in poems, songs,{{efn-ua|[[John Herald]], a [[bluegrass music|bluegrass]] singer, wrote a song dedicated to the extinction of the species and [[Martha (pigeon)|Martha]], the species' endling, that he titled "Martha (Last of the Passenger Pigeons)".<ref>{{cite web |title=Lyrics to "Martha (Last of the Passenger Pigeons)" |website=Johnherald.com |author-link=John Herald |last1=Herald |first1=J. |url=http://johnherald.com/martha.shtml |access-date=April 28, 2013}}</ref><ref>{{cite web |title=Martha: Last of the Passenger Pigeons |last1=Gebhart |first1=Parrish |format=video |website=[[YouTube]] |date=October 17, 2010 |url=https://www.youtube.com/watch?v=XFpaVfFIMFQ |access-date=December 12, 2013 |url-status=live |archive-url=https://ghostarchive.org/varchive/youtube/20211211/XFpaVfFIMFQ |archive-date=2021-12-11}}{{cbignore}}</ref> In connection with the centennial of Martha's death, the song was cited as evidence of her [[secular icon|iconic]] stature{{mdash}}a symbol of the wanton slaughter of these pigeons and the human-caused extinction of the species.<ref name="Harvey">{{cite journal |title=13 Memories of Martha, the Last Passenger Pigeon |last1=Harvey |first1=C. |last2=Newbern |first2=E. |date=August 29, 2014 |journal=[[Audubon Magazine]] |url=https://www.audubon.org/news/13-memories-martha-last-passenger-pigeon |access-date=March 3, 2016}}</ref><ref name="McLendon">{{cite journal |title=Ode to Martha, the last passenger pigeon |last1=McLendon |first1=R. |journal=[[Mother Nature Network]] |date=September 1, 2011 |url=https://www.treehugger.com/ode-to-martha-the-last-passenger-pigeon-4866790 |access-date=March 3, 2016 |quote=One of eastern North America's most iconic animals vanished forever on Sept. 1, 1914. Now, 97 years later, the passenger pigeon has become an icon for something else: manmade extinction.}}</ref>}} and fiction) and illustrated by many notable writers and artists, and is depicted in art to this day, for example in [[Walton Ford]]'s 2002 painting ''Falling Bough'', and [[National Medal of Arts]] winner [[John A. Ruthven]]'s 2014 mural in Cincinnati, which commemorates the 100th anniversary of Martha's death.<ref name="Fuller 2014 124–147"/> The "Project Passenger Pigeon" outreach group used the centennial of its extinction to spread awareness about human-induced extinction, and to recognize its relevance in the 21st century. It has been suggested that the passenger pigeon could be used as a "[[flagship]]" species to spread awareness of other threatened, but less well-known North American birds.<ref>{{cite journal |last1=Kyne |first1=P. M. |last2=Adams |first2=V. M. |title=Extinct flagships: linking extinct and threatened species |journal=Oryx |date=2016 |volume=51 |issue=3 |pages=471–476 |doi=10.1017/S0030605316000041 |doi-access=free}}</ref>

===Hunting===
[[File:Passenger pigeon shoot.jpg|left|thumb|Depiction of a shooting in northern Louisiana, Smith Bennett, 1875]]

The passenger pigeon was an important source of food for the people of North America.<ref name="Schorger129">{{Harvnb|Schorger|1955|p=129}}</ref> Native Americans ate pigeons, and tribes near nesting colonies would sometimes move to live closer to them and eat the juveniles, killing them at night with long poles.<ref name="Schorger1334">{{Harvnb|Schorger|1955|pp=133–134}}</ref> Many Native Americans were careful not to disturb the adult pigeons, and instead ate only the juveniles as they were afraid that the adults might desert their nesting grounds; in some tribes, disturbing the adult pigeons was considered a crime.<ref name="Schorger137">{{Harvnb|Schorger|1955|p=137}}</ref> Away from the nests, large nets were used to capture adult pigeons, sometimes up to 800 at a time.<ref name="Schorger139">{{Harvnb|Schorger|1955|p=139}}</ref> Low-flying pigeons could be killed by throwing sticks or stones. At one site in [[Oklahoma]], the pigeons leaving their roost every morning flew low enough that the [[Cherokee]] could throw clubs into their midst, which caused the lead pigeons to try to turn aside and in the process created a blockade that resulted in a large mass of flying, easily hit pigeons.<ref name="Schorger168"/> Among the game birds, passenger pigeons were second only to the [[wild turkey]] (''Meleagris gallopavo'') in terms of importance for the Native Americans living in the southeastern United States. The bird's fat was stored, often in large quantities, and used as butter. Archaeological evidence supports the idea that Native Americans ate the pigeons frequently prior to colonization.<ref name="Schorger134">{{Harvnb|Schorger|1955|p=134}}</ref>

[[File:Passenger pigeon capture.jpg|thumb|upright|1881 spread showing methods of trapping pigeons for shooting contests]]

What may be the earliest account of Europeans hunting passenger pigeons dates to January 1565, when the French explorer [[René Goulaine de Laudonnière|René Laudonnière]] wrote of killing close to 10,000 of them around [[Fort Caroline#Fort Caroline (1564–1565)|Fort Caroline]] in a matter of weeks:
{{Blockquote|There came to us a manna of wood pigeons in such great numbers, that over a span of about seven weeks, each day we killed more than two hundred with [[arquebus]]es in the woods around our fort.<ref name=Manna >{{cite book |last=Laudonnière |first=René de Goulaine de |title=L'histoire notable de la Floride située ès Indes Occidentales: contenant les trois voyages faits en icelle par certains Capitaines et Pilotes françois |date=1853 |location=Paris |publisher=Chez P. Jannet |page=136 |url=https://books.google.com/books?id=lohbAAAAQAAJ&pg=PA136}}</ref><ref>{{cite magazine |last1=MacNamara |first1=Charles |editor1-last=Miller |editor1-first=G.A. |title=Champlain as a Naturalist |magazine=The Canadian Field-Naturalist |volume=XL |issue=6 |location=Ottawa |publisher=Graphic Publishers |page=127 |url=https://archive.org/details/canadianfieldnat1926otta}}</ref>}}

This amounted to about one passenger pigeon per day for each person in the fort.<ref name=each >{{cite book |last=McCarthy |first=Kevin M. |title=Twenty Florida Pirates |date=1994 |location=Sarasota, FL |publisher=Pineapple Press |page=[https://archive.org/details/twentyfloridapir0000mcca/page/16 16] |isbn=978-1-56164-050-8 |url=https://archive.org/details/twentyfloridapir0000mcca |url-access=registration |quote=its leader, Rene de Laudonniere, had been there 200 soldiers without relief over a year, since June 1564..}}</ref>

After European colonization, the passenger pigeon was hunted with more intensive methods than the more [[sustainability|sustainable]] methods practiced by the natives.<ref name="Fuller 2014 72–88"/> Yet it has also been suggested that the species was rare prior to 1492, and that the subsequent increase in their numbers may be due to the decrease in the [[Indigenous peoples of the Americas|Native American]] population (who, as well as hunting the birds, competed with them for mast) caused by European immigration, and the supplementary food (agricultural crops) the immigrants imported<ref>{{cite book |last=Mann |first=C. C. |author-link=Charles C. Mann |title=1491: New Revelations of the Americas Before Columbus |publisher=[[Alfred A. Knopf]] |location=[[New York City |New York]] |isbn=978-1-4000-4006-3 |pages=[https://archive.org/details/1491newrevelatio00mann/page/315 315–318] |chapter=The Artificial Wilderness |year=2005 |title-link=1491: New Revelations of the Americas Before Columbus}}</ref> (a theory for which Joel Greenberg offered a detailed rebuttal in his book, ''A Feathered River Across the Sky'').<ref name="archaeology"/> The passenger pigeon was of particular value on the frontier, and some settlements counted on its meat to support their population.<ref name="Schorger130">{{Harvnb|Schorger|1955|p=130}}</ref><ref name="Schorger131">{{Harvnb|Schorger|1955|p=131}}</ref> The flavor of the flesh of passenger pigeons varied depending on how they were prepared. In general, juveniles were thought to taste the best, followed by birds fattened in captivity and birds caught in September and October. It was common practice to fatten trapped pigeons before eating them or storing their bodies for winter.<ref name="Schorger129"/> Dead pigeons were commonly stored by [[salting (food)|salting]] or [[pickling]] the bodies; other times, only the breasts of the pigeons were kept, in which case they were typically [[smoking (cooking)|smoked]]. In the early 19th century, commercial hunters began netting and shooting the birds to sell as food in city markets, and even as pig [[fodder]]. Once pigeon meat became popular, commercial hunting started on a prodigious scale.<ref name="Schorger131"/><ref name="Schorger144"/>

Passenger pigeons were shot with such ease that many did not consider them to be a game bird, as an amateur hunter could easily bring down six with one shotgun blast; a particularly good shot with both barrels of a shotgun at a roost could kill 61 birds.<ref name="Schorger186">{{Harvnb|Schorger|1955|p=186}}</ref><ref name="Schorger193">{{Harvnb|Schorger|1955|p=193}}</ref> The birds were frequently shot either in flight during migration or immediately after, when they commonly perched in dead, exposed trees.<ref name="Schorger186"/> Hunters only had to shoot toward the sky without aiming, and many pigeons would be brought down.<ref name="Fuller 2014 72–88">{{Harvnb|Fuller|2014|pp=72–88}}</ref> The pigeons proved difficult to shoot head-on, so hunters typically waited for the flocks to pass overhead before shooting them. Trenches were sometimes dug and filled with grain so that a hunter could shoot the pigeons along this trench.<ref name="Schorger192">{{Harvnb|Schorger|1955|p=192}}</ref> Hunters largely outnumbered trappers, and hunting passenger pigeons was a popular sport for young boys.<ref name="Schorger198">{{Harvnb|Schorger|1955|p=198}}</ref> In 1871, a single seller of ammunition provided three tons of powder and 16 tons (32,000&nbsp;lb) of shot during a nesting. In the latter half of the 19th century, thousands of passenger pigeons were captured for use in the [[sports shooting]] industry. The pigeons were used as living targets in shooting tournaments, such as "[[trap-shooting]]", the controlled release of birds from special traps. Competitions could also consist of people standing regularly spaced while trying to shoot down as many birds as possible in a passing flock.<ref name="Fuller 2014 72–88"/><ref name="Hume 2015">{{cite journal |last=Hume |first=J. P. |title=Large-scale live capture of Passenger Pigeons ''Ectopistes migratorius'' for sporting purposes: overlooked illustrated documentation |journal=Bulletin of the British Ornithologists' Club |volume=135 |series=2 |pages=174{{ndash}}184 |year=2015 |url=https://boc-online.org/passenger-pigeons-large-scale-live-capture}}</ref> The pigeon was considered so numerous that 30,000 birds had to be killed to claim the prize in one competition.<ref name="Fuller 2001"/>

[[File:Passenger Pigeon Net Cockburn 1829.jpg|thumb|left|Pigeon net in Canada, by [[James Pattison Cockburn]], 1829]]

Humans used a wide variety of other methods to capture and kill passenger pigeons. Nets were propped up to allow passenger pigeons entry, and then closed by knocking loose the stick that supported the opening, trapping twenty or more pigeons inside.<ref name="Schorger169">{{Harvnb|Schorger|1955|p=169}}</ref> Tunnel nets were also used to great effect, and one particularly large net was capable of catching 3,500 pigeons at a time.<ref name="Schorger172">{{Harvnb|Schorger|1955|p=172}}</ref> These nets were used by many farmers on their own property as well as by professional trappers.<ref name="Schorger170">{{Harvnb|Schorger|1955|p=170}}</ref> Food would be placed on the ground near the nets to attract the pigeons. [[Decoy]] or "stool pigeons" (sometimes blinded by having their eyelids sewn together) were tied to a stool. When a flock of pigeons passed by, a cord would be pulled that made the stool pigeon flutter to the ground, making it seem as if it had found food, and the flock would be lured into the trap.<ref name="Fuller 2014 72–88"/><ref name="Schorger1779">{{Harvnb|Schorger|1955|pp=177–179}}</ref><ref>{{cite journal |author=Paxson, H. D. |title=The last of the Wild Pigeon in Bucks County |pages=367{{ndash}}382 |journal=Collection of Papers Read Before the Bucks County Historical Society |volume=4 |year=1917 |url=https://archive.org/stream/collectionofpape04buck#page/n389/mode/1up}}</ref> Salt was also frequently used as bait, and many trappers set up near salt springs.<ref name="Schorger173">{{Harvnb|Schorger|1955|p=173}}</ref> At least one trapper used alcohol-soaked grain as bait to intoxicate the birds and make them easier to kill.<ref name="Schorger168">{{Harvnb|Schorger|1955|p=168}}</ref> Another method of capture was to hunt at a nesting colony, particularly during the period of a few days after the adult pigeons abandoned their nestlings, but before the nestlings could fly. Some hunters used sticks to poke the nestlings out of the nest, while others shot the bottom of a nest with a blunt arrow to dislodge the pigeon. Others cut down a nesting tree in such a way that when it fell, it would also hit a second nesting tree and dislodge the pigeons within.<ref name="Schorger141">{{Harvnb|Schorger|1955|p=141}}</ref> In one case, {{convert|6|km2|acre|abbr=on}} of large trees were speedily cut down to get birds, and such methods were common.<ref name="Fuller 2014 72–88"/> A severe method was to set fire to the base of a tree nested with pigeons; the adults would flee and the juveniles would fall to the ground.<ref name="Yeoman"/><ref name="Schorger142">{{Harvnb|Schorger|1955|p=142}}</ref> [[Sulfur]] was sometimes burned beneath the nesting tree to suffocate the birds, which fell out of the tree in a weakened state.<ref name="Schorger167">{{Harvnb|Schorger|1955|p=167}}</ref>

[[File:Decoy Passenger Pigeon.jpg|thumb|upright|Trapper Albert Cooper with blind [[decoy]] pigeons for luring wild birds, c.&nbsp;1870]]

By the mid-19th century, [[railroad]]s had opened new opportunities for pigeon hunters. While it was once extremely difficult to ship masses of pigeons to eastern cities, railway access permitted pigeon hunting to become commercialized.<ref name="Schorger144">{{Harvnb|Schorger|1955|p=144}}</ref> An extensive [[telegraph]] system was introduced in the 1860s, which improved communication across the United States, making it easier to spread information about the whereabouts of pigeon flocks.<ref name="Hume 2015"/> After being opened up to the railroads, the town of [[Plattsburgh (city), New York|Plattsburgh, New York]], is estimated to have shipped 1.8 million pigeons to larger cities in 1851 alone at a price of 31 to 56 cents a dozen. By the late 19th century, the trade of passenger pigeons had become commercialized. Large commission houses employed trappers (known as "pigeoners") to follow the flocks of pigeons year-round.<ref name="Schorger145">{{Harvnb|Schorger|1955|p=145}}</ref> A single hunter is reported to have sent three million birds to eastern cities during his career.<ref name="Ehrlich">{{cite web |title=The Passenger Pigeon |year=1988 |last1=Ehrlich |first1=P. R. |author-link1=Paul R. Ehrlich |last2=Dobkin |first2=D. S. |last3=Wheye |first3=D. |website=[[Stanford University]] |url=https://web.stanford.edu/group/stanfordbirds/text/essays/Passenger_Pigeon.html |access-date=March 3, 2012}}</ref> In 1874, at least 600 people were employed as pigeon trappers, a number which grew to 1,200 by 1881. Pigeons were caught in such numbers that by 1876, shipments of dead pigeons were unable to recoup the costs of the barrels and ice needed to ship them.<ref name="Schorger146">{{Harvnb|Schorger|1955|p=146}}</ref> The price of a barrel full of pigeons dropped to below fifty cents, due to overstocked markets. Passenger pigeons were instead kept alive so their meat would be fresh when killed, and sold once their market value had increased. Thousands of birds were kept in large pens, though the bad conditions led many to die from lack of food and water, and by fretting (gnawing) themselves; many rotted away before they could be sold.<ref name="Fuller 2014 50–69"/>

Hunting of passenger pigeons was documented and depicted in contemporaneous newspapers, wherein various trapping methods and uses were featured. The most often reproduced of these illustrations was captioned "Winter sports in northern Louisiana: shooting wild pigeons", and published in 1875. Passenger pigeons were also seen as [[agricultural pests]], because feeding flocks could destroy entire crops. The bird was described as a "perfect scourge" by some farming communities, and hunters were employed to "wage warfare" on the birds to save grain, as shown in another newspaper illustration from 1867 captioned as "Shooting wild pigeons in Iowa".<ref name="Hume 2015"/> When comparing these "pests" to the [[bison]] of the Great Plains, the valuable resource needed was not the species of animals but the agriculture which was consumed by said animal. The crops that were eaten were seen as marketable calories, proteins, and nutrients all grown for the wrong species.<ref>{{cite journal |last1=Whaples |first1=R. |year=2015 |title=A Feathered River Across the Sky: The Passenger Pigeon's Flight to Extinction |journal=[[The Independent Review]] |volume=19 |issue=3 |pages=443{{ndash}}6}}</ref><ref name=ext>{{cite journal |last1=Jackson |first1=J. A. |last2=Jackson |first2=B. |year=2007 |title=Extinction: the Passenger Pigeon, last hopes, letting go |journal=[[The Wilson Journal of Ornithology]] |volume=119 |issue=4 |pages=767{{ndash}}772|jstor=20456089 |doi=10.1676/1559-4491(2007)119[767:etpplh]2.0.co;2 |s2cid=85830808}}</ref>

===Decline and conservation attempts===
[[File:Mershon's The Passenger Pigeon (frontispiece, crop).jpg|thumb|left|upright|Male and female by [[Louis Agassiz Fuertes]], [[book frontispiece|frontispiece]] of [[William Butts Mershon]]'s 1907 ''The Passenger Pigeon'']]

The notion that the species could be driven to [[extinction]] was alien to the early colonists, because the number of birds did not appear to diminish, and also because the concept of extinction was yet to be defined. The bird seems to have been slowly pushed westward after the arrival of Europeans, becoming scarce or absent in the east, though there were still millions of birds in the 1850s. The population must have been decreasing in numbers for many years, though this went unnoticed due to the apparent vast number of birds, which clouded their decline.<ref name="Fuller 2014 50–69"/> In 1856 Bénédict Henry Révoil may have been one of the first writers to voice concern about the fate of the passenger pigeon, after witnessing a hunt in 1847:
{{Blockquote|Everything leads to the belief that the pigeons, which cannot endure isolation and are forced to flee or to change their way of living according to the rate at which North America is populated by the European inflow, will simply end by disappearing from this continent, and, if the world does not end this before a century, I will wager&nbsp;... that the amateur of ornithology will find no more wild pigeons, except those in the Museums of Natural History.<ref name="Fuller 2014 50–69"/>}}

[[File:Alabama bird day book (1915) (14751712302).jpg|thumb|upright|Life drawing by [[Charles R. Knight]], 1903]]
By the 1870s, the decrease in birds was noticeable, especially after the last large-scale nestings and subsequent slaughters of millions of birds in 1874 and 1878. By this time, large nestings only took place in the north, around the Great Lakes. The last large nesting was in [[Petoskey, Michigan]], in 1878 (following one in Pennsylvania a few days earlier), where 50,000 birds were killed each day for nearly five months. The surviving adults attempted a second nesting at new sites, but were killed by professional hunters before they had a chance to raise any young. Scattered nestings were reported into the 1880s, but the birds were now wary, and commonly abandoned their nests if persecuted.<ref name="Extinct Birds"/><ref name=SI/><ref name="Fuller 2014 50–69"/>

By the time of these last nestings, laws had already been enacted to protect the passenger pigeon, but these proved ineffective, as they were unclearly framed and hard to enforce. H.&nbsp;B. Roney, who witnessed the Petoskey slaughter, led campaigns to protect the pigeon, but was met with resistance, and accusations that he was exaggerating the severity of the situation. Few offenders were prosecuted, mainly some poor trappers, but the large enterprises were not affected.<ref name="Fuller 2014 50–69"/> In 1857, a bill was brought forth to the [[Ohio State Legislature]] seeking protection for the passenger pigeon, yet a Select Committee of the Senate filed a report stating that the bird did not need protection, being "wonderfully prolific", and dismissing the suggestion that the species could be destroyed.<ref>{{cite book |last1=Hornaday |first1=W. T. |author-link=William Temple Hornaday |place=New York |publisher=[[Charles Scribner's Sons]] |year=1913 |title=Our Vanishing Wild Life. Its Extermination and Preservation |url=https://www.gutenberg.org/files/13249/13249-h/13249-h.htm |access-date=February 29, 2012}} at [[Project Gutenberg]].</ref> Public protests against trap-shooting erupted in the 1870s, as the birds were badly treated before and after such contests. Conservationists were ineffective in stopping the slaughter. A bill was passed in the Michigan legislature making it illegal to net pigeons within {{convert|3|km|mi|abbr=on}} of a nesting area. In 1897, a bill was introduced in the Michigan legislature asking for a 10-year closed season on passenger pigeons. Similar legal measures were passed and then disregarded in Pennsylvania. The gestures proved futile and, by the mid-1890s, the passenger pigeon had almost completely disappeared, and was probably extinct as a breeding bird in the wild.<ref name="Hume 2015"/><ref name="Ehrlich"/> Small flocks are known to have existed at this point, since large numbers of birds were still being sold at markets. Thereafter, only small groups or individual birds were reported, many of which were shot on sight.<ref name="Fuller 2014 50–69"/>

===Last survivors===
{{See also|Martha (passenger pigeon)}}
[[File:Last known Passenger Pigeon.jpg|thumb|"Buttons", last confirmed wild passenger pigeon, [[Cincinnati Zoo]]]]

The last recorded nest and egg in the wild were collected in 1895 near Minneapolis. The last wild individual in Louisiana was discovered among a flock of mourning doves in 1896, and subsequently shot. Many late sightings are thought to be false or due to confusion with mourning doves.<ref name="Fuller 2014 50–69"/> The last fully authenticated record of a wild passenger pigeon was near [[Oakford, Illinois]], on March 12, 1901, when a male bird was killed, stuffed, and placed in [[Millikin University]] in [[Decatur, Illinois]], where it remains today. This was not discovered until 2014, when writer Joel Greenberg found out the date of the bird's shooting while doing research for his book ''A Feathered River Across the Sky.'' Greenberg also pointed out a record of a male shot near [[Laurel, Indiana]], on April 3, 1902, that was stuffed but later destroyed.<ref>{{cite book |last1=Greenberg |first1=Joel |title=A Feathered River Across the Sky: The Passenger Pigeon's Flight to Extinction |publisher=[[Bloomsbury Publishing |Bloomsbury USA]] |year=2014 |location=New York |isbn=978-1-62040-534-5}}</ref>

For many years, the last confirmed wild passenger pigeon was thought to have been shot near [[Sargents, Ohio|Sargents]], [[Pike County, Ohio]] on March 24, 1900, when a boy named Press Clay Southworth killed a female bird with a [[BB gun]].<ref name=SI/><ref name="Reeve">{{cite journal |last=Reeve |first=S. |title=Going Down in History |journal=Geographical |volume=73 |issue=3 |pages=60{{ndash}}64 |date=March 2001 |issn=0016-741X}}</ref> The boy did not recognize the bird as a passenger pigeon, but his parents identified it, and sent it to a taxidermist. The specimen, nicknamed "Buttons" due to the buttons used instead of glass eyes, was donated to the [[Ohio Historical Society]] by the family in 1915. The reliability of accounts after the Ohio, Illinois, and Indiana birds are in question. Ornithologist [[Alexander Wetmore]] claimed that he saw a pair flying near [[Independence, Kansas]], in April 1905.<ref>{{cite news |last1=Wetmore |first1=A. |title=Game Birds of Prairie, Forest and Tundra |date=October 1936 |page=495 |work=[[National Geographic (magazine) |National Geographic]]}}</ref><ref>{{cite journal |last1=McKinley |first1=D. |year=1960 |title=A History of the Passenger Pigeon in Missouri |journal=Auk |volume=77 |issue=4 |pages=399–420 |jstor=4082414 |doi=10.2307/4082414 |doi-access=free |url=https://sora.unm.edu/node/20911}}</ref> On May 18, 1907, U.S. President [[Theodore Roosevelt]] claimed to have seen a "flock of about a dozen two or three times on the wing" while on retreat at his cabin in Pine Knot, Virginia, and that they lit on a dead tree "in such a characteristically pigeon-like attitude"; this sighting was corroborated by a local gentleman whom he had "rambled around with in the woods a good deal" and whom he found to be "a singularly close observer."<ref>{{cite web |title=Theodore Roosevelt Signed Archive Passenger Pigeons {{!}} Raab Collection |website=The Raab Collection |language=en-US |url=https://www.raabcollection.com/presidential-autographs/roosevelt-pigeons |access-date=2023-03-12}}</ref><ref>{{cite web |title=Letter from Theodore Roosevelt to C. Hart Merriam |website=theodorerooseveltcenter.org |url=https://www.theodorerooseveltcenter.org/Research/Digital-Library/Record/ImageViewer?libID=o199420 |access-date=2023-03-12}}</ref> In 1910, the [[American Ornithologists' Union]] offered a reward of $3,000 for discovering a nest— {{Inflation|US|3000|1910|fmt=eq|cursign=$}}.{{inflation/fn|US}}<ref>{{cite web |title=Passenger Pigeon |website=South Dakota Game Fish & Parks |last1=Stukel |first1=E. D. |date=January–February 2005 |url=http://gfp.sd.gov/wildlife/critters/birds/passenger-pigeon.aspx |access-date=August 7, 2016}}</ref><ref>{{cite news |work=[[The New York Times]] |title=Reward for Wild Pigeons. Ornithologists Offer $3,000 for the Discovery of Their Nests |date=April 4, 1910 |place=Boston, Massachusetts |url=https://timesmachine.nytimes.com/timesmachine/1910/04/04/104928421.pdf |access-date=February 29, 2012}}</ref>

[[File:Passenger pigeon aviary.jpg|thumb|left|Whitman's aviary with passenger pigeons and other species, 1896/98]]

Most captive passenger pigeons were kept for exploitative purposes, but some were housed in zoos and aviaries. Audubon alone claimed to have brought 350 birds to England in 1830, distributing them among various noblemen, and the species is also known to have been kept at [[London Zoo]]. Being common birds, these attracted little interest, until the species became rare in the 1890s. By the turn of the 20th century, the last known captive passenger pigeons were divided in three groups; one in Milwaukee, one in Chicago, and one in Cincinnati. There are claims of a few further individuals having been kept in various places, but these accounts are not considered reliable today. The Milwaukee group was kept by David Whittaker, who began his collection in 1888, and possessed fifteen birds some years later, all descended from a single pair.<ref name="Extinct Birds"/><ref name="Fuller 2014 92–121"/>

The Chicago group was kept by [[Charles Otis Whitman]], whose collection began with passenger pigeons bought from Whittaker beginning in 1896. He had an interest in studying pigeons, and kept his passenger pigeons with other pigeon species. Whitman brought his pigeons with him from Chicago to Massachusetts by railcar each summer. By 1897, Whitman had bought all of Whittaker's birds, and upon reaching a maximum of 19 individuals, he gave seven back to Whittaker in 1898. Around this time, a series of photographs were taken of these birds; 24 of the photos survive. Some of these images have been reproduced in various media, copies of which are now kept at the [[Wisconsin Historical Society]]. It is unclear exactly where, when, and by whom these photos were taken, but some appear to have been taken in Chicago in 1896, others in Massachusetts in 1898, the latter by a J.&nbsp;G. Hubbard. By 1902, Whitman owned sixteen birds. His pigeons laid many eggs, but few hatched, and many hatchlings died. A newspaper inquiry was published that requested "fresh blood" to the flock which had now ceased breeding. By 1907, he was down to two female passenger pigeons that died that winter, and was left with two infertile male hybrids, whose subsequent fate is unknown. By this time, only four (all males) of the birds Whitman returned to Whittaker were alive, and these died between November 1908 and February 1909.<ref name="Fuller 2014 92–121">{{Harvnb|Fuller|2014|pp=92–121}}</ref><ref name="Rothschild">{{cite book |last=Rothschild |first=W. |author-link=Walter Rothschild, 2nd Baron Rothschild |title=Extinct Birds |publisher=[[Hutchinson (publisher)|Hutchinson & Co]] |year=1907 |location=London |pages=167{{ndash}}170 |url=https://archive.org/stream/extinctbirdsatte00roth#page/166/mode/2up}}</ref>

[[File:Hornaday Frontispiece.jpg|right|upright=1.5|thumb|"''The Folly of 1857 and the Lesson of 1912''", frontispiece to [[William Temple Hornaday|William T. Hornaday]]'s ''Our vanishing wild life'' (1913), showing [[Martha (passenger pigeon)|Martha]] in life, the [[endling]] of the species.]]
The Cincinnati Zoo, one of the oldest zoos in the United States, kept passenger pigeons from its beginning in 1875. The zoo kept more than twenty individuals in a {{convert|10|by|12|ft|m|adj=on|spell=in}} cage.<ref name="Fuller 2014 92–121"/> Passenger pigeons do not appear to have been kept at the zoo due to their rarity, but to enable guests to have a closer look at a native species.<ref name=Schorger28>{{Harvnb|Schorger|1955|p=28}}</ref> Recognizing the decline of the wild populations, Whitman and the Cincinnati Zoo consistently strove to breed the surviving birds, including attempts at making a rock dove foster passenger pigeon eggs.<ref>{{cite journal |last=D'Elia |first=J. |title=Evolution of Avian Conservation Breeding with Insights for Addressing the Current Extinction Crisis |journal=Journal of Fish and Wildlife Management |volume=1 |issue=2 |pages=189–210 |year=2010 |doi=10.3996/062010-JFWM-017 |doi-access=free|bibcode=2010JWFM....1..189D }}</ref> In 1902, Whitman gave a female passenger pigeon to the zoo; this was possibly the individual later known as Martha, which would become the last living member of the species. Other sources argue that Martha was hatched at the Cincinnati Zoo, lived there for 25 years, and was the descendant of three pairs of passenger pigeons purchased by the zoo in 1877. It is thought this individual was named Martha because her last cage mate was named George, thereby honoring [[George Washington]] and his wife [[Martha Washington|Martha]], though it has also been claimed she was named after the mother of a zookeeper's friends.<ref name="Fuller 2014 92–121"/><ref name=Schorger27>{{Harvnb|Schorger|1955|p=27}}</ref>

In 1909, Martha and her two male companions at the Cincinnati Zoo became the only known surviving passenger pigeons. One of these males died around April that year, followed by George, the remaining male, on July 10, 1910.<ref name=Schorger28/> It is unknown whether the remains of George were preserved. Martha soon became a celebrity due to her status as an [[endling]], and offers of a $1,000 reward ({{inflation|US|1000|1909|fmt=eq}}){{inflation/fn|US}} for finding a mate for her brought even more visitors to see her. During her last four years in solitude (her cage was {{convert|5.4|by|6|m|ft|abbr=on}}), Martha became steadily slower and more immobile; visitors would throw sand at her to make her move, and her cage was roped off in response.<ref name="Fuller 2014 92–121"/><ref name=Shell>{{cite journal |last=Shell |first=H. R. |title=The Face of Extinction |journal=[[Natural History (magazine) |Natural History]] |volume=113 |issue=4 |page=72 |date=May 2004 |issn=0028-0712}}</ref> Martha died of old age on September 1, 1914, and was found lifeless on the floor of her cage.<ref name=Shufeldt/><ref name=Schorger29>{{Harvnb|Schorger|1955|p=29}}</ref> It was claimed that she died at 1&nbsp;p.m., but other sources suggest she died some hours later.<ref name="Fuller 2014 92–121"/> Depending on the source, Martha was between 17 and 29 years old at the time of her death, although 29 is the generally accepted figure.<ref name=Schorger30>{{Harvnb|Schorger|1955|p=30}}</ref> At the time, it was suggested that Martha might have died from an [[apoplexy|apoplectic stroke]], as she had suffered one a few weeks before dying.<ref name=ElPaso>{{cite news |title=Last Passenger Pigeon Dies |newspaper=[[El Paso Times |El Paso Morning Times]] |location=El Paso, Texas |page=6 |date=September 14, 1914 |url=https://texashistory.unt.edu/ark:/67531/metapth197161/m1/6/zoom/}}</ref> Her body was frozen into a block of ice and sent to the [[Smithsonian Institution]] in Washington, where it was skinned, dissected, photographed, and mounted.<ref name=Shufeldt/><ref name=Yeoman>{{cite web |last1=Yeoman |first1=B. |title=Why the Passenger Pigeon Went Extinct |website=[[Audubon (magazine) |Audubon Magazine]] |year=2014 |url=https://www.audubon.org/magazine/may-june-2014/why-passenger-pigeon-went-extinct |access-date=October 8, 2024 |url-status=live |archive-url=https://web.archive.org/web/20150121163434/http://www.audubonmagazine.org/articles/birds/why-passenger-pigeon-went-extinct |archive-date=January 21, 2015}}</ref> As she was [[molting]] when she died, she proved difficult to stuff, and previously shed feathers were added to the skin. Martha was on display for many years, but after a period in the museum vaults, she was put back on display at the Smithsonian's [[National Museum of Natural History]] in 2015.<ref name="Fuller 2014 92–121"/> A memorial statue of Martha stands on the grounds of the Cincinnati Zoo, in front of the "Passenger Pigeon Memorial Hut", formerly the aviary wherein Martha lived, now a [[National Historic Landmark]]. Incidentally, the last specimen of the extinct [[Carolina parakeet]], named "Incus," died in Martha's cage in 1918; the stuffed remains of that bird are exhibited in the "Memorial Hut".<ref name="SI"/><ref name="r4">{{cite web |title=Martha – Passenger Pigeon Memorial Hut |location=Cincinnati, Ohio |website=[[Roadside America]] |url=https://www.roadsideamerica.com/story/10663 |access-date=February 29, 2012}}</ref>

===Extinction causes===
[[File:Martha, the last Passenger Pigeon. Natural History Museum, June, 2015. Digital photo, cropped and brightened.jpg|upright|thumb|left|Martha at the [[Smithsonian Museum]], 2015]]

The main reasons for the extinction of the passenger pigeon were the massive scale of hunting, the rapid loss of habitat, and the extremely social lifestyle of the bird, which made it highly vulnerable to the former factors. [[Deforestation]] was driven by the need to free land for agriculture and expanding towns, but also due to the demand for lumber and fuel. About 728,000&nbsp;km<sup>2</sup> (180 million acres) were cleared for farming between 1850 and 1910. Though there are still large woodland areas in eastern North America, which support a variety of wildlife, it was not enough to support the vast number of passenger pigeons needed to sustain the population. In contrast, very small populations of nearly extinct birds, such as the [[kākāpō]] (''Strigops habroptilus'') and the [[takahē]] (''Porphyrio hochstetteri''), have been enough to keep those species extant to the present. The combined effects of intense hunting and deforestation has been referred to as a "[[Blitzkrieg]]" against the passenger pigeon, and it has been labeled one of the greatest and most senseless human-induced extinctions in history.<ref name="Fuller 2014 72–88"/><ref name="Hung 2014"/><ref name="Hume 2015"/> As the flocks dwindled in size, the passenger pigeon population decreased below the threshold necessary to propagate the species,<ref>{{cite journal |last1=Halliday |first1=T. |title=The extinction of the passenger pigeon ''Ectopistes migratorius'' and its relevance to contemporary conservation |journal=[[Biological Conservation (journal) |Biological Conservation]] |volume=17 |issue=2 |pages=157–162 |year=1980 |bibcode=1980BCons..17..157H |doi=10.1016/0006-3207(80)90046-4}}</ref> an example of the [[Allee effect]].<ref>{{cite web |title=Passenger Pigeon/Allee effect |website=kevintshoemaker.github.io |url=https://kevintshoemaker.github.io/NRES-470/LECTURE5.html |access-date=2020-09-25}}</ref>

[[File:Passenger pigeon shooting in Iowa.jpg|thumb|Pigeons being shot to save crops in Iowa, 1867]]
The 2014 genetic study that found natural fluctuations in population numbers prior to human arrival also concluded that the species routinely recovered from lows in the population, and suggested that one of these lows may have coincided with the intensified hunting by humans in the 1800s, a combination which would have led to the rapid extinction of the species. A similar scenario may also explain the rapid extinction of the [[Rocky Mountain locust]] (''Melanoplus spretus'') during the same period.<ref name="Hung 2014"/> It has also been suggested that after the population was thinned out, it would be harder for few or solitary birds to locate suitable feeding areas.<ref name="Extinct Birds"/> In addition to the birds killed or driven away by hunting during breeding seasons, many nestlings were also orphaned before being able to fend for themselves. Other, less convincing contributing factors have been suggested at times, including mass drownings, [[Newcastle disease]], and migrations to areas outside their original range.<ref name="iucn status 19 November 2021"/><ref name="Fuller 2014 72–88"/>

The extinction of the passenger pigeon aroused public interest in the [[conservation movement]], and resulted in new laws and practices which prevented many other species from becoming extinct.<ref name="SI"/> The rapid decline of the passenger pigeon has influenced later assessment methods of the extinction risk of endangered animal populations. The [[International Union for Conservation of Nature]] (IUCN) has used the passenger pigeon as an example in cases where a species was declared "at risk" for extinction even though population numbers are high.<ref name=ext/>

Naturalist [[Aldo Leopold]] paid tribute to the vanished species in a monument dedication held by the Wisconsin Society for Ornithology at [[Wyalusing State Park]], [[Wisconsin]], which had been one of the species' social roost sites.<ref>{{cite web |title=Passenger Pigeon Monument |date=December 2003 |publisher=Wisconsin Historical Society |url=https://www.wisconsinhistory.org/Records/Image/IM34684 |access-date=October 8, 2024}}</ref> Speaking on May 11, 1947, Leopold remarked:
{{Blockquote|Men still live who, in their youth, remember pigeons. Trees still live who, in their youth, were shaken by a living wind. But a decade hence only the oldest oaks will remember, and at long last only the hills will know.<ref name="Leopold">{{cite book |title=[[A Sand County Almanac]]: And Sketches Here and There |last=Leopold |first=Aldo |orig-year=1949 |year=1989 |publisher=[[Oxford University Press]] |location=[[New York City |New York]] |isbn=0-19-505928-X |page=109}}</ref>}}

===Potential resurrection of the species===
[[File:Ectopistes migratorius ULaval 2.jpg|thumb|Taxidermied male and female, [[Laval University]] Library]]
Today, at least 1,532 passenger pigeon skins (along with 16 skeletons) still exist, spread across many institutions all over the world.<ref name=Greenway>{{cite book |last=Greenway |first=J. C. |title=Extinct and Vanishing Birds of the World |publisher=American Committee for International Wild Life Protection 13 |location=New York |year=1967 |pages=304{{ndash}}311 |isbn=978-0-486-21869-4}}</ref><ref name="Aberrant"/> It has been suggested that the passenger pigeon should be revived when available technology allows it (a concept which has been termed "[[de-extinction]]"), using genetic material from such specimens. In 2003, the [[Pyrenean ibex]] (''Capra pyrenaica pyrenaica'', a subspecies of the [[Iberian ibex]]) was the first extinct animal to be cloned back to life; the clone lived for only seven minutes before dying of lung defects.<ref name="back to life"/><ref>{{cite web |title='Bringing Back the Passenger Pigeon' Meeting convened at Harvard Medical School in Boston |website=[[Long Now Foundation]] |date=2013-02-07 |url=http://longnow.org/revive/passenger-pigeon-workshop/ |access-date=April 10, 2015}}</ref> A hindrance to cloning the passenger pigeon is the fact that the DNA of museum specimens has been contaminated and fragmented, due to exposure to heat and oxygen. American geneticist [[George M. Church]] has proposed that the passenger pigeon genome can be reconstructed by piecing together DNA fragments from different specimens. The next step would be to splice these genes into the [[stem cell]]s of rock pigeons (or [[band-tailed pigeon]]s), which would then be transformed into egg and sperm cells, and placed into the eggs of rock pigeons, resulting in rock pigeons bearing passenger pigeon sperm and eggs. The offspring of these would have passenger pigeon traits, and would be further bred to favor unique features of the extinct species.<ref name="back to life"/><ref name="NatGeo 2013">{{cite web |last=Zimmer |first=C. |title=Bringing them back to life |website=National Geographic |year=2013 |url=http://ngm.nationalgeographic.com/2013/04/125-species-revival/zimmer-text |access-date=October 29, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20161212002128/http://ngm.nationalgeographic.com/2013/04/125-species-revival/zimmer-text |archive-date=December 12, 2016}}</ref><ref>{{cite web |last1=Landers |first1=J. |title=Scientists look to revive the long-extinct passenger pigeon |newspaper=[[The Washington Post]] |year=2013 |url=https://www.washingtonpost.com/national/health-science/scientists-look-to-revive-the-long-extinct-passenger-pigeon/2013/07/08/3d1323d4-b9a1-11e2-aa9e-a02b765ff0ea_story.html |access-date=November 6, 2014}}</ref> The American non-profit organization [[Revive & Restore]] is currently pursuing the idea.<ref>{{cite web |title=The Great Passenger Pigeon Comeback |language=en-US |url=https://reviverestore.org/about-the-passenger-pigeon/ |access-date=2023-08-10}}</ref>

The general idea of re-creating extinct species has been criticized, since the large funds needed could be spent on conserving currently threatened species and habitats, and because conservation efforts might be viewed as less urgent. In the case of the passenger pigeon, since it was very social, it is unlikely that enough birds could be created for revival to be successful, and it is unclear whether there is enough appropriate habitat left for its reintroduction. Furthermore, the parent pigeons that would raise the cloned passenger pigeons would belong to a different species, with a different way of rearing young.<ref name="back to life">{{cite web |last=Lewis |first=T. |website=NBC News |title=How to bring extinct animals back to life |year=2013 |url=https://www.nbcnews.com/science/how-bring-extinct-animals-back-life-8C10995683 |access-date=August 25, 2013}}</ref><ref name="NatGeo 2013"/>