NORTH AMERIOAN BIRDS. .287 



A lighter-colored form of the Nighthawk, found In the unwooded portions of 

 Western United States. Its general habits, nesting,- etc., are the same as those of 

 0. virginanus; the eggs average paler; size 1.20x.S5. 



4206. FLORIDA NIGHTHAWK. Ohordeiles virginiamis ehapmani Coue's. 

 Geog. Dist. — Florida and the Gulf coast of Texas, south In winter to South America. 



This race of the Nighthawk is dedicated by Mt. Sennett to Mr. Prank M. Chap- 

 man, the well-known ornithologist and author. It is a somewhat darker-colored 

 bird and is smaller than the common Nighthawk. In all respects its habits, nesting 

 and eggs do not differ from those of C. virffinianus. Mr. Crandall has a series of 

 thirty-eight sets of the eggs of this geographical race, eighteen of which were taken 

 in Manatee and Hillsboro counties, Florida, between the dates of April 27 and July 

 7; twenty sets on islands off the Mississippi coast of the Gulf of Mexico between 

 the dates of May 21 and 25. The average size of the seventy-six eggs is 1.16x.84; the 

 longest is, 1.29x.86; shortest, 1.05x.77; broadest, 1.20x.92; narrowest, 1.05x.77 inches. 



420c. SEWKETT'S NIGHTHAWK. Ohordeiles virginianus sennetti (Coues.) 

 Geog. Dist. — Treeless region of the Great Plains, from the Saskatchewan south to 

 Texas. 



This geographic race is Of a silvery grayish-white predominating above, the 

 white below is greatly in excess of the narrow irregular or broken dark bars and 

 little or no rufous anywhere. 



421. TEXAN NIGHTHAWK. Chordeiles acuUpennis texensis (Lawr.) Geog. 

 Dist. — Southern border of the United States, from Texas to Southern California, 

 north into Southern Utah; south to Cape St. Lucas and Veragua. 



This subspecies has quite an extended range. It is known to occur as far north 

 as San Joaquin and Stanislaus counties in California; in Southern Nevada; in the 

 lower Santa Clara Valley, Utah; the desert regions of Arizona; southern portions of 

 New Mexico, and it is found to be a common summer resident of the southern and 

 western portions of Texas. The Texan Nighthawk is smaller than the foregoing 

 subspecies, the general tone of the plumage lighter, and it differs otherwise. Mr. 

 Sennett describes its flight as resembling that of the Whip-poor-will, but it does not 

 indulge in the perpendicular descents accompanied by the whir of wings so char- 

 acteristic of -C. virginianus. On the Lower Rio Grande eggs were obtained as early 

 as April 26, and fresh ones found as late as May 19. They were always laid on the 

 bare, hot ground. Dr. Merrill states that the notes of this species are a curious mew- 

 ing call difficult to describe. He found the eggs in the vicinity of Brownsville, Texas, 

 usually deposited in exposed situations, among sparse chaparral on ground baked 

 almost as hard as a brick by the intense heat of the sun. One set was found on a 

 small piece of tin, near a frequented path. Mr. Rachford informs me that in Jeffer- 

 son county, Texas, this species usually deposits its two eggs on the ground, in a well- 

 beaten cow-path; the nesting season begins from about May 10th, and eggs may be 

 found in the latter part of June. Dr. Merrill states that the eggs vary const „rably, 

 but exactly resemble the surface on which they are placed. The ground-color is 

 usually clay; some are very sparingly dotted with brown; others mottled with light 

 brown and ooscure lilac; some are so thickly marbled with brown and lilac on a 

 dark ground as to give them a granite-like appearance. They average 1.07x.77. 



422. BLACK SWIFT. -Cypseloides niger (Gmel.) Geog. Dist.— Rocky Moun- 

 tain region (Colorado), west to the Pacific coast; north to British Columbia, and 

 south to Lower California, Mexico, Costa Rica and the West Indies. 



