THE GENUS CHORDEILES SWAINSON — OBERHOLSER. 93 



canyons, bottomlands, and other kinds of open country. Its flight, 

 though strong and graceful, is usually rather low. Its notes, uttered 

 both on the Ving and while the bird is at rest, are peculiar, and dif- 

 ficult of description, some of them not distantly resembling the call 

 of a little owl. This nighthawk is often gregarious, and large num- 

 bers sometimes congregate, usually during the migration seasons. 

 Its food consists of lepidoptera and various other insects, captured 

 largely on the wing, though also by hopping after them on the 



ground. 



This species builds no nest, but lays its eggs on the ground, even 

 though bare, hard, stony, or gravelly, and usually in a more or less 

 exposed situation, although sometimes at the base of a bush. One or 

 two broods are reared ; and in the United States the earliest recorded 

 date for eggs is April 2T, the latest, August 6. The eggs are two in 

 number, pale grayish or whitish, finely dotted and otherwise marked 

 over the whole surface with lilac, various shades of gray, drab, and 

 slate color. The female often remains on the eggs until almost 



touched. 



History.— The earliest account of the species is apparently that 

 of Buffon,! ^1^0, in 1779, described the bird from Guiana under the 

 name " L'Engoulevent acutipenne de la Guyane." Upon this de- 

 scription and the accompanying plate by d'Aubenton,^ Boddaert in 

 1783 based his name C apnmulgus aeutlpennis.^ This same sub- 

 species was subsequently diagnosed as new, twice by Gmelin,* and 

 still more recently no less than six times by various other authors.^ 

 Not until 1839 was another valid form described, when the bird of 

 (Chile and) western Peru was named Capriinulgus exilis by Les- 

 son.« The same race was later redescribed twice by Tschudi,^ and 

 once by Peale.« The Texas bird was made known as Chordeiles tex- 

 ensis by George N. Lawrence in 1856,^ though at that time its real 

 relationship with Chordeiles acutipennis was not suspected. The 

 two additional subspecies in the present paper result from the sep- 

 aration of the Lower California bird as Chordeiles acutipenms m- 

 ferior,^' and the bird from Yucatan and southern Mexico as Chor- 

 deiles acutipennis micromeris}^ 



1 Hist. Nat. des Oiseaux, orig. ed., vol. 6, 1779, pp. 547-548. 

 s Planch. Enlum. d'Hist. Nat., No. 732. 

 sTnhl Planch. Enlum. d'Hist. Nat, 1783, p. 46. 



.SHmiC?'-«i^'-««««^ Syst. Nat., vol. 1. pt. 2. 1789, p. 1031; Caprimulgus acutus. 

 ibid. 



B See p. 94. 



6 Rev. Zool., 1839, p. 44. 



8 United States Explor. Exped., vol. 8, Mamm. and Ornith., 1848, p. 172. 

 « Ann. Lye. Nat. Hist. N. Y., vol. 6, December, 1856, p. 167. 

 10 See p. 109. 

 u See p. 100. 



