Editing Passenger pigeon (section)

==Description==
[[File:Naturalis Biodiversity Center - RMNH.AVES.110090 - Ectopistes migratorius (Linnaeus, 1766) - Passenger Pigeon - specimen - video.webm|left|thumbtime=0:07|thumb|Turntable video of an adult male specimen at [[Naturalis Biodiversity Center]]]]

The passenger pigeon was [[sexually dimorphic]] in size and coloration. It weighed between {{convert|260|and|340|g|oz|abbr=on}}.<ref name="Blockstein 2"/> The adult male was about {{convert|390 to 410|mm|in|abbr=on|1}} in length.<ref name="Gibbs 319">{{cite book |last1=Gibbs |first1=D. |last2=Barnes |first2=E. |last3=Cox |first3=J. |title=Pigeons and Doves: A Guide to the Pigeons and Doves of the World |publisher=[[Pica Press]] |year=2001 |location=Sussex |isbn=978-1-873403-60-0 |pages=318{{ndash}}319}}</ref> It had a bluish-gray head, nape, and hindneck. On the sides of the neck and the upper mantle were iridescent display feathers that have variously been described as being a bright bronze, violet, or golden-green, depending on the angle of the light. The upper back and wings were a pale or slate gray tinged with olive brown, that turned into grayish-brown on the lower wings. The lower back and [[rump (animal)|rump]] were a dark blue-gray that became grayish-brown on the upper tail-[[covert feather]]s. The greater and median wing-covert feathers were pale gray, with a small number of irregular black spots near the end. The primary and secondary feathers of the wing were a blackish-brown with a narrow white edge on the outer side of the secondaries. The two central tail feathers were brownish gray, and the rest were white.<ref name="Fuller 2014 30–47"/><ref name="Gibbs 319"/>

The tail pattern was distinctive as it had white outer edges with blackish spots that were prominently displayed in flight.<ref name="Gibbs 319"/> The lower throat and breast were richly pinkish-[[rufous]], grading into a paler pink further down, and into white on the abdomen and undertail covert feathers. The undertail coverts also had a few black spots. The bill was black, while the feet and legs were a bright coral red. It had a [[carmine]]-red iris surrounded by a narrow purplish-red eye-ring.<ref name="Gibbs 319"/> The wing of the male measured {{convert|196 to 215|mm|in|abbr=on}}, the tail {{convert|175 to 210|mm|in|abbr=on}}, the bill {{convert|15 to 18|mm|in|abbr=on}}, and the [[tarsus (skeleton)|tarsus]] was {{convert|26 to 28|mm|in|abbr=on}}.<ref name="Fuller 2014 30–47"/>

[[File:Naturalis Biodiversity Center - RMNH.AVES.110091 - Ectopistes migratorius (Linnaeus, 1766) - Passenger Pigeon - specimen - video.webm|thumbtime=0:14|thumb|Turntable video of an adult female specimen at Naturalis]]

The adult female passenger pigeon was slightly smaller than the male at {{convert|380 to 400|mm|in|abbr=on|1}} in length. It was duller than the male overall, and was a grayish-brown on the forehead, crown, and nape down to the [[scapular]]s, and the feathers on the sides of the neck had less [[iridescence]] than those of the male. The lower throat and breast were a buff-gray that developed into white on the belly and undertail-coverts. It was browner on the upperparts and paler buff brown and less rufous on the underparts than the male. The wings, back, and tail were similar in appearance to those of the male except that the outer edges of the primary feathers were edged in buff or rufous buff.<ref name="Fuller 2014 30–47"/><ref name="Gibbs 319"/> The wings had more spotting than those of the male.<ref name="Blockstein 2"/> The tail was shorter than that of the male, and the legs and feet were a paler red. The iris was orange red, with a grayish blue, naked orbital ring. The wing of the female was {{convert|180 to 210|mm|in|abbr=on}}, the tail {{convert|150 to 200|mm|in|abbr=on}}, the bill {{convert|15 to 18|mm|in|abbr=on}}, and the tarsus was {{convert|25 to 28|mm|in|abbr=on}}.<ref name="Fuller 2014 30–47"/>

[[File:Naturalis Biodiversity Center - RMNH.AVES.110088 - Ectopistes migratorius (Linnaeus, 1766) - Passenger Pigeon - specimen - video.webm|left|thumbtime=0:07|thumb|Turntable video of a juvenile female specimen at Naturalis]]

The juvenile passenger pigeon was similar in [[plumage]] to the adult female, but lacked the spotting on the wings, and was a darker brownish-gray on the head, neck, and breast. The feathers on the wings had pale gray fringes (also described as white tips), giving it a scaled look. The secondaries were brownish-black with pale edges, and the [[tertial feathers]] had a rufous wash. The primaries were also edged with a rufous-brown color. The neck feathers had no iridescence. The legs and feet were dull red, and the iris was brownish, and surrounded by a narrow carmine ring.<ref name="Fuller 2014 30–47"/><ref name="Gibbs 319"/> The plumage of the sexes was similar during their first year.<ref name=Greenway/>

Of the hundreds of surviving skins, only one appears to be aberrant in color{{mdash}}an adult female from the collection of [[Walter Rothschild]], [[Natural History Museum at Tring]]. It is a washed brown on the upper parts, wing covert, secondary feathers, and tail (where it would otherwise have been gray), and white on the primary feathers and underparts. The normally black spots are brown, and it is pale gray on the head, lower back, and upper-tail covert feathers, yet the iridescence is unaffected. The brown [[mutation]] is a result of a reduction in [[eumelanin]], due to incomplete synthesis ([[oxidation]]) of this [[pigment]]. This sex-linked mutation is common in female wild birds, but it is thought the white feathers of this specimen are instead the result of bleaching due to exposure to sunlight.<ref name="Aberrant">{{cite journal |last1=Hume |first1=J. P. |last2=van Grouw |first2=H. |pages=168{{ndash}}193 |year=2014 |title=Colour aberrations in extinct and endangered birds |journal=[[Bulletin of the British Ornithologists' Club]] |volume=134}}</ref>

[[File:Passenger Pigeon skeleton.jpg|thumb|Skeleton of a male bird, 1914]]

The passenger pigeon was physically adapted for speed, endurance, and maneuverability in flight, and has been described as having a streamlined version of the typical pigeon shape, such as that of the generalized [[rock dove]] (''Columba livia''). The wings were very long and pointed, and measured {{convert|220|mm|in|abbr=on}} from the wing-chord to the primary feathers, and {{convert|120|mm|in|abbr=on}} to the secondaries. The tail, which accounted for much of its overall length, was long and wedge-shaped (or graduated), with two central feathers longer than the rest. The body was slender and narrow, and the head and neck were small.<ref name="Fuller 2014 30–47"/><ref name="SI">{{cite web |author=Department of Vertebrate Zoology, National Museum of Natural History |title=The Passenger Pigeon |website=Encyclopedia Smithsonian |publisher=[[Smithsonian Institution]] |date=March 2001 |url=https://www.si.edu/spotlight/passenger-pigeon |access-date=October 8, 2024}}</ref><ref name="Fuller 2014 162–168"/>

The internal anatomy of the passenger pigeon has rarely been described. [[Robert W. Shufeldt]] found little to differentiate the bird's [[osteology]] from that of other pigeons when examining a male skeleton in 1914, but [[Julian P. Hume]] noted several distinct features in a more detailed 2015 description. The pigeon's particularly large breast muscles indicated a powerful flight ([[musculus pectoralis major]] for downstroke and the smaller [[bird anatomy#Muscular system|musculus supracoracoideus]] for upstroke). The [[coracoid]] bone (which connects the [[scapula]], [[furcula]], and [[sternum]]) was large relative to the size of the bird, {{convert|33.4|mm|in|abbr=on}}, with straighter shafts and more robust articular ends than in other pigeons. The furcula had a sharper V-shape and was more robust, with expanded articular ends. The scapula was long, straight, and robust, and its [[distal]] end was enlarged. The sternum was very large and robust compared to that of other pigeons; its [[keel (bird anatomy)|keel]] was {{convert|25|mm|in|abbr=on}} deep. The overlapping [[uncinate processes of ribs|uncinate processes]], which stiffen the ribcage, were very well developed. The wing bones ([[humerus]], [[radius (bone)|radius]], [[ulna]], and [[carpometacarpus]]) were short but robust compared to other pigeons. The leg bones were similar to those of other pigeons.<ref name="Fuller 2014 162–168">{{Harvnb|Fuller|2014|pp=162–168}}</ref><ref>{{cite journal |jstor=4071953 |title=Osteology of the Passenger Pigeon (''Ectopistes migratorius'') |journal=[[The Auk]] |volume=31 |issue=3 |pages=358–362 |year=1914 |last1=Shufeldt |first1=R. W. |doi=10.2307/4071953 |url=https://www.biodiversitylibrary.org/part/86752}}</ref><ref name=Shufeldt>{{cite journal |jstor=4071611 |title=Anatomical and other notes on the Passenger Pigeon (''Ectopistes migratorius'') lately living in the Cincinnati Zoological Gardens |journal=The Auk |volume=32 |issue=1 |pages=29–41 |year=1915 |last1=Shufeldt |first1=R. W. |doi=10.2307/4071611 |url=https://www.biodiversitylibrary.org/page/15937222#page/87/mode/1up}}</ref>

===Vocalizations===
[[File:Passenger pigeon notes.jpg|thumb|300px|[[Musical note]]s documenting male vocalizations, compiled by [[Wallace Craig]], 1911]]

The noise produced by flocks of passenger pigeons was described as deafening, audible for miles away, and the bird's voice as loud, harsh, and unmusical. It was also described by some as clucks, twittering, and cooing, and as a series of low notes, instead of an actual song. The birds apparently made croaking noises when building nests, and bell-like sounds when mating. During feeding, some individuals would give [[alarm calls]] when facing a threat, and the rest of the flock would join the sound while taking off.<ref name="Fuller 2014 30–47">{{cite book |last=Fuller |first=E. |author-link=Errol Fuller |title=The Passenger Pigeon |publisher=[[Princeton University Press]] |year=2014 |location=Princeton and Oxford |isbn=978-0-691-16295-9}} pp. 30–47.<!--Please keep page number(s) outside the cite template so that sfns with other page numbers can use the full citation. --></ref><ref name="Blockstein 8"/><ref name="Fuller 2001"/>

In 1911, American behavioral scientist [[Wallace Craig]] published an account of the gestures and sounds of this species as a series of descriptions and [[musical notation]]s, based on observation of C. O. Whitman's captive passenger pigeons in 1903. Craig compiled these records to assist in identifying potential survivors in the wild (as the physically similar mourning doves could otherwise be mistaken for passenger pigeons), while noting this "meager information" was likely all that would be left on the subject. According to Craig, one call was a simple harsh "keck" that could be given twice in succession with a pause in between. This was said to be used to attract the attention of another pigeon. Another call was a more frequent and variable scolding. This sound was described as "kee-kee-kee-kee" or "tete! tete! tete!", and was used to call either to its mate or towards other creatures it considered to be enemies. One variant of this call, described as a long, drawn-out "tweet", could be used to call down a flock of passenger pigeons passing overhead, which would then land in a nearby tree. "Keeho" was a soft cooing that, while followed by louder "keck" notes or scolding, was directed at the bird's mate. A nesting passenger pigeon would also give off a stream of at least eight mixed notes that were both high and low in tone and ended with "keeho". Overall, female passenger pigeons were quieter and called infrequently. Craig suggested that the loud, strident voice and "degenerated" musicality was the result of living in populous colonies where only the loudest sounds could be heard.<ref name="Blockstein 8"/><ref name="Craig 1911">{{cite journal |last=Craig |first=W. |title=The expressions of emotion in the pigeons. III. The Passenger Pigeon (''Ectopistes migratorius'' Linn.) |journal=The Auk |series=4 |volume=28 |issue=4 |pages=408–427 |year=1911 |jstor=4071160 |doi=10.2307/4071160 |url=https://archive.org/stream/jstor-4071160/4071160#page/n1/mode/2up}}</ref>