The common nighthawk, Chordeiles minor is widely distributed throughout North America during their breeding season but migrates to South America for the winter. Chordeiles minor is commonly observed during the summer chasing insects at both dusk and dawn. Externally, the common nighthawk resembles other caprimulgiforms by its cryptic plumage, large eyes, flattened head, and large mouth. In flight, a white wing patch is visible on the primaries (Poulin et al., 1996).
Chordeiles minor is allocated to 'Caprimulgiformes'. A group that traditionally includes Caprimulgidae (nightjars, including C. minor), Nyctibiidae (potoos), Steatornithidae (oilbirds), Aegothelidae (owlet-nightjars), and Podargidae (frogmouths). The caprimulgiforms, however, may compose a paraphyletic assemblage with respect to hummingbirds and swifts (Mayr, 2002). The monophyly of Caprimulgidae is not questioned, and a number of osteological characters support a sister-group relationship between this taxon and Nyctibiidae. These include a cone-like bony protrusion at the caudal margin of the foramen nervi optici, extremely widened palatine, paraocciptal process that protrudes strongly in the ventral direction, mandible with an intraramal joint, the caudal half of the mandible is greatly widened and dorso-ventrally flattened, and the caudal end of the mandible is unusually small with a very short lateral condyle and stout medial process (Mayr, 2002).
The fossil record of 'caprimulgiform' birds extends back to the lower Eocene of Wyoming. A nearly complete skeleton of Prefica nivea from the Green River Formation was described by Olson (1987). A number of well-preserved specimens also are known from the middle Eocene deposits of Messel (Germany) (Mayr, 2001).
Baumel, J. J., A. S. King, J. E. Breazile, H. E. Evans, and J. C. Vanden Berge (eds.). 1993. Handbook of Avian Anatomy: Nomina Anatomica Avium, Second Edition. Publication of the Nuttall Ornithological Club, number 23. Nuttall Ornithological Club, Cambridge, Massachusetts, 779 pp.
Mayr, G. 1999. Caprimulgiform birds from the middle Eocene of Messel (Hessen, Germany). Journal of Vertebrate Paleontology 19:521-532.
Mayr, G. 2001. Comments on the osteology of Masillapodargus longipes Mayr 1999 and Paraprefica major Mayr 1999, caprimulgiform birds from the Middle Eocene of Messel (Hessen, Germany). Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 2001:65-76.
Mayr, G. 2002. Osteological evidence for paraphyly of the avian order Caprimulgiformes (nightjars and allies). Journal für Ornithologie 143:82-97.
Olson, S. L. 1987. An early Eocene oilbird from the Green River Formation of Wyoming (Caprimulgiformes:Steatornithidae). Documents des laboratoires de geologie de la Faculte des sciences de Lyon 99:57-69.
Poulin, R. G., S. D. Grindal, and R. M. Brigham. 1996. Common Nighthawk. The Birds of North America 213:1-20.
Shufeldt, R. W. 1885. Contribution to the comparative osteology of the Trochilidae, Caprimulgidae, and Cypselidae. Proceedings of the Zoological Society of London 1885:886-915.
Chordeiles minor on the Animal Diversity Web (Univ. of Michigan Museum of Zoology).
Images of C. minor on AvesPhoto.com.
Images of C. minor on CalPhotos, Berkeley's Digital Library Project.