Editing Passenger pigeon (section)

===Predators and parasites===
[[File:Passenger pigeon.jpg|thumb|upright|Immature bird; the young were vulnerable to predators after leaving the nest]]

Nesting colonies attracted large numbers of predators, including [[American mink]]s (''Neogale vison''), [[long-tailed weasel]]s (''Neogale frenata''), [[American marten]]s (''Martes americana''), and [[raccoon]]s (''Procyon lotor'') that preyed on eggs and nestlings, [[birds of prey]], such as [[owl]]s, [[hawk]]s, and [[eagle]]s that preyed on nestlings and adults, and [[gray wolf|wolves]] (''Canis lupus''), [[fox]]es (''Urocyon cinereoargenteus'' and ''Vulpes vulpes''), [[bobcat]]s (''Lynx rufus''), [[American black bear]]s (''Ursus americanus''), and [[cougar]]s (''Puma concolor'') that preyed on injured adults and fallen nestlings. Hawks of the genus ''[[Accipiter]]'' and falcons pursued and preyed upon pigeons in flight, which in turn executed complex aerial maneuvers to avoid them; [[Cooper's hawk]] (''Accipiter cooperii'') was known as the "great pigeon hawk" due to its successes, and these hawks allegedly followed migrating passenger pigeons.<ref name="Blockstein 10"/> While many predators were drawn to the flocks, individual pigeons were largely protected due to the sheer size of the flock, and overall little damage could be inflicted on the flock by predation.<ref name="Blockstein 10"/> Despite the number of predators, nesting colonies were so large that they were estimated to have a 90% success rate if not disturbed.<ref name="Blockstein 15"/> After being abandoned and leaving the nest, the very fat juveniles were vulnerable to predators until they were able to fly. The sheer number of juveniles on the ground meant that only a small percentage of them were killed; [[predator satiation]] may therefore be one of the reasons for the extremely social habits and communal breeding of the species.<ref name="Fuller 2014 30–47"/><ref name="Fuller 2014 72–88"/>

Two parasites have been recorded on passenger pigeons. One species of [[Philopteridae|phtilopterid]] [[louse]], ''[[Columbicola extinctus]]'', was originally thought to have lived on just passenger pigeons and to have become [[coextinct]] with them. This was proven inaccurate in 1999 when ''C.&nbsp;extinctus'' was rediscovered living on band-tailed pigeons.<ref name="Clayton1999">{{cite journal |last=Clayton |first=D. H. |author2=Price, R. D. |title=Taxonomy of New World Columbicola (Phthiraptera: Philopteridae) from the Columbiformes (Aves), with descriptions of five new species |journal=Annals of the Entomological Society of America |volume=92 |issue=5 |pages=675{{ndash}}685 |year=1999 |doi=10.1093/aesa/92.5.675 |url=https://darwin.biology.utah.edu/PDFs/42.pdf |access-date=October 8, 2024 |url-status=live |archive-date=April 25, 2012 |archive-url=https://web.archive.org/web/20120425124314/http://darwin.biology.utah.edu/PubsHTML/PDF-Files/42.pdf}}</ref><ref name="Price2000"/> This, and the fact that the related louse ''C.&nbsp;angustus'' is mainly found on cuckoo-doves, further supports the relation between these pigeons, as the phylogeny of lice broadly mirrors that of their hosts.<ref name=Johnson/> Another louse, ''[[Campanulotes|Campanulotes defectus]]'', was thought to have been unique to the passenger pigeon, but is now believed to have been a case of a contaminated specimen, as the species is considered to be the still-extant ''[[Campanulotes|Campanulotes flavus]]'' of Australia.<ref name="Price2000">{{cite journal |last=Price |first=R. D. |author2=Clayton, D. H. |author3=Adams, R. J. |title=Pigeon Lice Down Under: Taxonomy of Australian ''Campanulotes'' (Phthiraptera: Philopteridae), with a description of ''C. durdeni'' n.sp. |journal=[[Journal of Parasitology]] |volume=86 |issue=5 |pages=948–950 |year=2000 |jstor=3284803 |pmid=11128516 |doi=10.2307/3284803 |url=https://darwin.biology.utah.edu/PDFs/47.pdf |access-date=October 8, 2024 |url-status=live |archive-url=https://web.archive.org/web/20100610153220/http://darwin.biology.utah.edu/PubsHTML/PDF-Files/47.pdf |archive-date=June 10, 2010}}</ref> There is no record of a wild pigeon dying of either disease or parasites.<ref name="Blockstein 15"/>