Editing Nightjar (section)

==Systematics==

=== Caprimulgiformes ===
Previously, all members of the orders [[Apodiformes]], [[Owlet-nightjar|Aegotheliformes]], [[Potoo|Nyctibiiformes]], [[Frogmouth|Podargiformes]], and [[Oilbird|Steatornithiformes]] were lumped alongside nightjars in the Caprimulgiformes. In 2021, the [[International Ornithologists' Union|International Ornithological Congress]] redefined the Caprimulgiformes as only applying to nightjars, with potoos, frogmouths, oilbirds, and owlet-nightjars all being reclassified into their own orders.<ref>{{Cite web|title=Taxonomic Updates – IOC World Bird List|url=https://www.worldbirdnames.org/new/updates/taxonomy/|access-date=2021-07-29|language=en-US}}</ref> See [[Strisores]] for more info about the disputes over the taxonomy of Caprimulgiformes. A phylogenetic analysis found that the extinct family [[Archaeotrogonidae]], known from the [[Eocene]] and [[Oligocene]] of Europe, are the closest known relatives of nightjars.<ref name=":0">{{Cite journal|last=Mayr|first=Gerald|date=2021-07-18|editor-last=Lautenschlager|editor-first=Stephan|title=An early Eocene fossil from the British London Clay elucidates the evolutionary history of the enigmatic Archaeotrogonidae (Aves, Strisores)|journal=Papers in Palaeontology|volume=7|issue=4|language=en|pages=2049–2064|doi=10.1002/spp2.1392|issn=2056-2799|doi-access=free}}</ref>

=== Caprimulgidae ===
Traditionally, nightjars have been divided into two subfamilies—the [[Caprimulginae]], or typical nightjars with 79 known species, and the [[Chordeilinae]], or [[nighthawk]]s of the New World, with 10 known species. The groups are similar in most respects, but the typical nightjars have rictal bristles, longer bills, and softer plumage.  The underside of the claw of the middle toe is comb-like with serrations.<ref>{{cite book |author=Austin, Oliver Luther |title=Birds of the world : a survey of the twenty-seven orders and one hundred and fifty-five families |publisher=Hamlyn |year=1962 |page=162}}</ref> Their soft plumage is [[Crypsis|cryptically coloured]] to resemble bark or leaves, and some species, unusual for birds, perch along a branch rather than across it, helping to conceal them during the day. The subfamilies of nightjars have similar characteristics, including small feet, of little use for walking, and long, pointed wings.

The [[common poorwill]], ''Phalaenoptilus nuttallii'', is unique as a bird that undergoes a form of hibernation, becoming torpid and with a much reduced body temperature for weeks or months, although other nightjars can enter a state of torpor for shorter periods.<ref>{{cite journal|vauthors=Lane JE, Brigham RM, Swanson DL|year=2004|title=Daily torpor in free-ranging whip-poor-wills (''Caprimulgus vociferus'')|journal=[[Physiological and Biochemical Zoology]]|volume=77|issue=2|pages=297–304|doi=10.1086/380210|pmid=15095249|s2cid=32140353}}</ref>

In their pioneering [[DNA–DNA hybridisation]] work, [[Charles Sibley]] and [[Jon E. Ahlquist]] found that the genetic difference between the eared nightjars and the typical nightjars was, in fact, greater than that between the typical nightjars and the nighthawks of the New World. Accordingly, they placed the eared nightjars in a separate [[Family (biology)|family]], the [[Eurostopodidae]] (9 known species), but the family has not yet been widely adopted.

Subsequent work, both morphological and genetic, has provided support for the separation of the typical and the eared nightjars, and some authorities have adopted this Sibley–Ahlquist recommendation, and also the more far-reaching one to group all the [[owl]]s (traditionally Strigiformes) together in the Caprimulgiformes. The listing below retains a more orthodox arrangement, but recognises the eared nightjars as a separate group. For more detail and an alternative classification scheme, see [[Caprimulgiformes]] and [[Sibley–Ahlquist taxonomy]].

{{clade gallery |align=right |width=400px;
|caption1=Phylogeny of Caprimulgidae<ref name="Boyd">{{cite web| website=John Boyd's website |last=Boyd|first=John|year=2007|title=''Caprimulgidae: Nightjars, Nighthawks'' |url=http://jboyd.net/Taxo/Caprimulgidae.pdf |access-date= 30 December 2017}}</ref>
|cladogram1=
{{clade|style=font-size:100%;line-height:90%;
  |grouplabel1={{clade labels |label1=[[Eurostopodinae]] |top1=5% 
                               |label2=[[Caprimulginae]]<br/>(typical nightjars)  |top2=45%
                               |label3=[[Chordeilinae]]<br/>(nighthawks) |top3=91%
                               }}
|1={{Clade
  |1=''[[Eurostopodus]]'' |bar1=purple
  |2={{Clade
    |1=''[[Lyncornis]]''  |bar1=purple
    
    |2={{Clade
      |1=''[[Gactornis]]''|bar1=cyan 
      |2={{Clade  |bar1=cyan
        |1={{clade 
          |label1=Neotropical |sublabel1=nightjars
          |1={{Clade
            |1=''[[Nyctiprogne]]''
            |2={{Clade
              |1=''[[Lurocalis]]''
              |2={{Clade
                |1=''[[Hydropsalis]]''
                |2={{Clade
                  |1=''[[Nyctidromus]]''&nbsp;
                  |2=''[[Nyctipolus]]''
                   }}
                 }}
               }}
             }}
           }}
        |2={{Clade
          |label1=Poorwills |bar1=cyan
          |1={{Clade
            |1=''[[Siphonorhis]]''
            |2={{Clade
              |1=''[[Nyctiphrynus]]''
              |2={{Clade
                |1=''[[Phalaenoptilus]]''
                |2=''[[Antrostomus]]''
                 }}
               }}
             }}
          |2={{Clade  |bar1=cyan |bar2=red
            |2={{Clade 
              |1=''[[Podager]]''
              |2=''[[Chordeiles]]''
               }}
            |1={{Clade  
              |1=''[[Veles (bird)|Veles]]''
              |2=''[[Caprimulgus]]''
               }}
             }}
           }}
         }}
       }}
     }}
   }}
}}
}}
* †''[[Ventivorus]]'' <small>Mourer-Chauviré 1988</small>
* '''Subfamily [[Eurostopodinae]]'''<ref>{{cite web |website=[[IOC World Bird List]] | version=v8.1 |url=http://www.worldbirdnames.org/IOC_8.1_vs_other_lists.xlsx |title=''Comparison of IOC 8.1 with other world lists'' | access-date=30 December 2017}}</ref>
** Genus ''[[Eurostopodus]]'' (7 species)
** Genus ''[[Lyncornis]]'' (2 species)
* '''Subfamily [[Caprimulginae]]''' (typical nightjars)
** Genus ''[[Gactornis]]'' – collared nightjar
** Genus ''[[Nyctipolus]]'' (2 species)
** Genus ''[[Nyctidromus]]'' (2 species)
** Genus ''[[Hydropsalis]]'' (4 species)
** Genus ''[[Siphonorhis]]'' (2 species)
** Genus ''[[Nyctiphrynus]]'' (4 species)
** Genus ''[[Phalaenoptilus]]'' – common poorwill
** Genus ''[[Antrostomus]]'' (12 species)
** Genus ''[[Caprimulgus]]'' (40 species, including the [[European nightjar]])
** Genus ''[[Setopagis]]'' (4 species) 
** Genus ''[[Uropsalis]]'' (2 species)
** Genus ''[[Macropsalis]]'' – long-trained nightjar
** Genus ''[[Eleothreptus]]'' (2 species)
** Genus ''[[Systellura]]'' (2 species)
* '''Subfamily [[Chordeilinae]]''' (nighthawks)
** Genus ''[[Chordeiles]]'' (6 species; includes ''[[Podager]]'')
** Genus ''[[Nyctiprogne]]'' (2 species)
** Genus ''[[Lurocalis]]'' (2 species)

Also see a [[list of nightjars]], sortable by common and binomial names.

<gallery widths="200px" heights="165px">
Image:Lesser Nighthawk.jpg|[[Lesser nighthawk]]
Image:Mlongipennis.png|[[Standard-winged nightjar]]
Image:Nyctidromus albicollisDF28N04B1.jpg|[[Pauraque]]
File:Şivanxapînok.jpg|Nightjar
</gallery>